Thorazine dose for hiccups


Thorazine is the brand name of the prescription drug chlorpromazine, which is used to treat certain mental illnesses such as schizophrenia, the manic phase of bipolar disorder, severe behavioral problems in kids, and other psychotic disorders.

The medicine can also be used to treat nausea, vomiting, nervousness before surgery, acute intermittent porphyria (a condition that causes natural substances to build up in the body and may cause pain and changes in behavior), and tetanus.

Thorazine is in a class of drugs called phenothiazines, which work by altering the activity of certain natural substances in the brain.

Thorazine for Hiccups

This medication can be used to treat hiccups that last a month or longer. Hiccups are involuntary contractions of the diaphragm, which is the muscle that separates your chest from your abdomen.

It’s rare for hiccups to last for months, but they may, in some cases. If your hiccups do not stop after three days of taking Thorazine, you should talk to your doctor about trying a different medication.

Thorazine Warnings

Older adults with dementia who take Thorazine are at an increased risk for developing life-threatening conditions such as heart failure, a fast/irregular heartbeat, and pneumonia. The drug is not approved for use in older adults with dementia.

It may take several weeks before you feel the full benefits of Thorazine. You shouldn’t stop taking this drug without first talking to your doctor.

You should stop taking Thorazine immediately if you experience twitching or uncontrollable movements of your eyes, lips, tongue, face, arms, or legs. These could be signs of dangerous side effects.

Before taking Thorazine, you should tell your doctor if you have or have ever had:

  • Emphysema, asthma, or a lung or bronchial tube infection
  • Glaucoma (an eye condition that causes increased pressure)
  • Breast cancer
  • Seizures
  • An abnormal electroencephalogram (EEG)
  • An enlarged prostate or urinary problems
  • Any condition that affects the production of blood cells by your bone marrow
  • Heart, liver, or kidney disease
  • Pheochromocytoma (a tumor on the gland near the kidneys)

You should also alert your physician if you plan to work with organophosphorus insecticides, which are chemicals used to kill insects. Also, tell your doctor if you had to stop taking a drug for mental illness in the past because of severe side effects.

This medicine may cause dizziness, fast heartbeat, fainting, or lightheadedness, especially when you get up quickly from a lying position. You can avoid this problem by getting out of bed slowly.

Tell your doctor you are taking Thorazine before having any type of surgery, including dental procedures. You should also tell your healthcare provider that you are taking this medicine before having an X-ray of the spine.

Thorazine may make it harder for your body to cool down after it gets very hot, so use caution in extreme heat or during vigorous exercise and drink plenty of fluids when the weather is hot.

Pregnancy and Thorazine

Thorazine has not been assigned a formal pregnancy category by the Food and Drug Administration (FDA). It’s sometimes used during pregnancy for treating nausea and vomiting, but studies have been conflicting, with some showing it may cause harm to an unborn baby.

Thorazine may cause problems in newborns following delivery if it’s taken during the last months of pregnancy. You should tell your doctor if you are pregnant or plan to become pregnant while taking Thorazine.

This medicine can pass into breast milk and may harm a breastfeeding baby. You shouldn’t use Thorazine without first talking to your doctor if you are breastfeeding.



Hiccups are an underreported respiratory complication that can significantly impair an individual’s quality of life. Responsible for at least 4000 hospital admissions annually, they often are not considered significant in the need to care for a patient’s other pressing comorbidities such as malignancy.1


Hiccups occur secondary to an involuntary spasm of the diaphragm and intercostal muscles, which is followed by the sudden closure of the glottis generating the “hic” sound. These involuntary spasms occur at a rate of 4 to 60 per minute and predominantly involve the left hemidiaphragm.1 The pathogenesis of hiccups is complex with a variety of etiologies, resulting in the neurophysiologic effect of the condition (Table 1).1-4

The hiccup reflex arc is composed of efferent and afferent limbs, as well as a central hiccup center. The nerves that are involved in this reflex include the vagus, phrenic, and elements of the sympathetic nervous chain—primarily in the thoracic region.1,5 This chain of nerves can be activated at multiple points, making the true cause of an individual’s hiccups hard to discern and treat. In addition, there is a male predominance of those with hiccups in most reports.1 Most hiccups are benign and self-limiting with cessation in minutes; however, some can last longer and become persistent or intractable hiccups, which are defined as lasting longer than 48 hours and 1 month, respectively.1,5

When diagnosing intractable hiccups, a careful physical and laboratory review should be performed to evaluate the myriad of possible causes. Intractable hiccups can result in anxiety, increased depression, sleep loss, impaired nutrition and fluid intake, aspiration, and induction of cardiac arrhythmias via activation of underlying cardiac pathology.1,5 This may result in significant impairment, and more rarely, death of the patient.


Self-limited hiccups do not require intervention as they will generally resolve without causing significant distress. Although there is little scientific evidence to support their use, it is common for people to try a variety of nonpharmacologic interventions to resolve their hiccups. Common interventions include the pressure or stimulation of different body areas, sudden frightening experiences, ingestion of sugar or a glass of liquid, black pepper–induced sneezes, or breathing into a paper bag.1

Patients with persistent or intractable hiccups often require pharmacologic intervention to alleviate the condition or complications. The only US Food and Drug Administration–approved hiccup remedy is chlorpromazine, which may not be useful in many patients because of its associated side effects listed in Table 2.2,4-20

There are no randomized, adequately powered clinical trials to determine the efficacy of pharmaceuticals for the treatment of hiccups. Many agents have been tried, with anecdotal success, and are hypothesized to work via a variety of neural mechanisms to decrease the activity of irritated nerves via sodium, calcium, or gamma-aminobutyric acid (GABA)-enervated pathways (Table 2). Each agent has a different risk-to-benefit ratio, and when assessing which agent to use, it is important to consider the patient’s level of organ function, tolerance to side effects, and risk for drug interactions.

Older anticonvulsants such as phenytoin, valproic acid, and carbamazepine were previously used, but have largely been replaced with dopamine antagonists (eg, chlorpromazine, haloperidol, metoclopramide), GABA enhancers (baclofen, gabapentin), or calcium channel blockers (nifedipine, nimodipine). In severe cases, intravenous lidocaine, which blocks sodium channels, has been used to resolve postoperative hiccups, although this practice is limited because of the risk for cardiac side effects.1 Nebulized lidocaine has also been used in the palliative care setting to manage refractory hiccups.1 Although diazepam is a well-documented cause of hiccups, midazolam has been used to terminate hiccups and may be useful in the setting of terminal sedation or delirium.8 Methylphenidate may be useful to try in the sedated patient.6 Acupuncture has been an effective nonpharmacologic intervention in some patients, and the use of phrenic nerve blocks has been helpful in intractable hiccups.21 Multiple agents have been combined in attempts to manage hiccups with variable effects; however, the limiting factor is generally the additive side effects, especially sedation.20

Currently, there is little guidance on which agent should be used initially for hiccups of different etiologies. Because of the larger body of literature, most practitioners use chlorpromazine, metoclopramide, or baclofen as the initial treatment modality; a trial of multiple single agents or combinations of agents is also common. Some practitioners believe that baclofen may be the most effective agent, although it is slower to take effect than other agents.2 Most agents are continued for several days after cessation of hiccups, then weaned off as tolerated. Some patients’ hiccups will recur, requiring the medication to be restarted. The goal is then to wean to the lowest effective dose.

In conclusion, although there are many reports of agents that help with the management of intractable hiccups, little current evidence exists regarding which agent, at what dose, and for which etiology should be used initially in patients. Agent and dose selection should be based on individual patient risks and comorbidities to achieve the best effect with minimal adverse consequences.

Brand Names: Ormazine, Thorazine

Generic Name: chlorpromazine (oral/injection)

  • What is chlorpromazine (Ormazine, Thorazine)?
  • What are the possible side effects of chlorpromazine (Ormazine, Thorazine)?
  • What is the most important information I should know about chlorpromazine (Ormazine, Thorazine)?
  • What should I discuss with my healthcare provider before using chlorpromazine (Ormazine, Thorazine)?
  • How should I use chlorpromazine (Ormazine, Thorazine)?
  • What happens if I miss a dose (Ormazine, Thorazine)?
  • What happens if I overdose (Ormazine, Thorazine)?
  • What should I avoid while using chlorpromazine (Ormazine, Thorazine)?
  • What other drugs will affect chlorpromazine (Ormazine, Thorazine)?
  • Where can I get more information (Ormazine, Thorazine)?

What is chlorpromazine (Ormazine, Thorazine)?

Chlorpromazine is an anti-psychotic medication in a group of drugs called phenothiazines (FEEN-oh-THYE-a-zeens).

Chlorpromazine is used to treat psychotic disorders such as schizophrenia or manic-depression in adults.

Chlorpromazine is also used in adults to treat nausea and vomiting, anxiety before surgery, chronic hiccups, acute intermittent porphyria, and symptoms of tetanus.

In children ages 1 through 12 years, chlorpromazine is used to treat severe behavioral problems (such as combative or explosive behavior) or hyperactivity with excessive motor activity.

Chlorpromazine may also be used for purposes not listed in this medication guide.

What are the possible side effects of chlorpromazine (Ormazine, Thorazine)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Long-term use of chlorpromazine can cause a serious movement disorder that may not be reversible. The longer you use chlorpromazine, the more likely you are to develop this disorder, especially if you are a an older adult.

Call your doctor at once if you have:

  • uncontrolled muscle movements in your face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement);
  • stiffness in your neck, tightness in your throat, trouble breathing or swallowing;
  • a light-headed feeling, like you might pass out;
  • confusion, agitation, feeling jittery, trouble sleeping;
  • weakness;
  • breast swelling or discharge;
  • a seizure;
  • jaundice (yellowing of the skin or eyes);
  • low white blood cell counts–fever, chills, mouth sores, skin sores, sore throat, cough, trouble breathing, feeling light-headed; or
  • severe nervous system reaction–very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Some side effects may be more likely in older adults.

Common side effects may include:

  • drowsiness;
  • dry mouth or stuffy nose;
  • blurred vision;
  • constipation; or
  • impotence, trouble having an orgasm.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the most important information I should know about chlorpromazine (Ormazine, Thorazine)?

Call your doctor at once if you have uncontrollable movements of your eyes, lips, tongue, face, arms, or legs. These could be early signs of dangerous side effects.

Chlorpromazine is not approved for use in older adults with dementia-related conditions.


Before taking chlorpromazine,

  • tell your doctor and pharmacist if you are allergic to chlorpromazine; other phenothiazines such as fluphenazine, perphenazine, prochlorperazine (Compazine), promethazine (Phenergan), thioridazine, and trifluoperazine; or any other medications.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: anticoagulants (blood thinners) such as warfarin (Coumadin); antidepressants; antihistamines; atropine (in Motofen, in Lomotil, in Lonox); barbiturates such as pentobarbital (Nembutal), phenobarbital (Luminal), and secobarbital (Seconal); cancer chemotherapy; diuretics (water pills); epinephrine (Epipen); guanethidine (not available in the US); ipratropium (Atrovent); lithium (Eskalith, Lithobid); medications for anxiety, irritable bowel disease, mental illness, motion sickness, Parkinson’s disease, ulcers, or urinary problems; medications for seizures such as phenytoin (Dilantin); narcotic medications for pain; propranolol (Inderal); sedatives; sleeping pills; and tranquilizers. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you have or have ever had asthma; emphysema (a lung disease that causes shortness of breath); an infection in your lungs or bronchial tubes (tubes that bring air to the lungs); trouble keeping your balance; glaucoma (condition in which increased pressure in the eye can lead to gradual loss of vision); breast cancer; pheochromocytoma (tumor on a small gland near the kidneys); seizures; an abnormal electroencephalogram (EEG; test that records electrical activity in the brain); any condition that affects the production of blood cells by your bone marrow; or heart, liver, or kidney disease. Also tell your doctor if you have ever had to stop taking a medication for mental illness due to severe side effects or if you plan to work with organophosphorus insecticides (a type of chemical used to kill insects).
  • if you will be using chlorpromazine to treat nausea and vomiting, it is important to tell your doctor about any other symptoms you are experiencing, especially listlessness; drowsiness; confusion; aggression; seizures; headaches; problems with vision, hearing, speech, or balance; stomach pain or cramps; or constipation. Nausea and vomiting that is experienced along with these symptoms may be a sign of a more serious condition that should not be treated with chlorpromazine.
  • tell your doctor if you are pregnant, especially if you are in the last few months of your pregnancy, or if you plan to become pregnant or are breast-feeding. If you become pregnant while taking chlorpromazine, call your doctor. Chlorpromazine may cause problems in newborns following delivery if it is taken during the last months of pregnancy.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking chlorpromazine.
  • if you are having a myelogram (x-ray examination of the spine), tell your doctor and the radiographer that you are taking chlorpromazine. Your doctor will probably tell you not to take chlorpromazine for 2 days before the myelogram and for one day after the myelogram.
  • you should know that this medication may make you drowsy and may affect your thinking and movements. Do not drive a car or operate machinery until you know how this medication affects you.
  • ask your doctor about the safe use of alcohol during your treatment with chlorpromazine. Alcohol can make the side effects of chlorpromazine worse.
  • plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Chlorpromazine may make your skin sensitive to sunlight.
  • you should know that chlorpromazine may cause dizziness, lightheadedness, fast heartbeat, and fainting, especially when you get up too quickly from a lying position. This is most common at the beginning of treatment with chlorpromazine, especially after the first dose. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.
  • you should know that chlorpromazine may make it harder for your body to cool down when it gets very hot. Tell your doctor if you plan to do vigorous exercise or be exposed to extreme heat.



It was found that the dropout of patients was as high as 30%. Initially, 142 patients were taken; of those 142, 100 patients came for regular follow-up and responded well to the drugs.

Among dropouts due to nonresponse to drugs, the chlorpromazine group was composed of 75% and the risperidone group composed of 25% patients.

It was found that the mean PANSS score for positive symptoms decreased for chlorpromazine from 30.02 to 9.92 while the mean PANSS score for positive symptoms decreased for risperidone from 27.96 to 7.7 in 1 year. This indicates that both drugs are good in treating positive symptoms of schizophrenia, such as delusions, conceptual disorganization, hallucinatory behavior, excitement, grandiosity, suspiciousness, and hostility. Reduction in the positive symptoms was equal, that is, approximately 70% for both the drugs as compared with the first visit.

In the present comparative study, the negative symptoms in patients taking risperidone and chlorpromazine, risperidone was found to be superior to chlorpromazine in controlling the negative symptoms such as blunted affect, emotional withdrawal, poor rapport, apathetic, social withdrawal, difficulty in abstract thinking, lack of spontaneity, and flow of conversation and stereotyped thinking. The reduction in the negative symptoms was 30% for chlorpromazine and 74% for risperidone as compared with the first visit.

In our study the general symptoms of schizophrenia were reduced significantly by both drugs as evident for a decrease in the mean PANSS score for chlorpromazine slides from 61.42 to 20.6 and for risperidone from 56.4 to 14.26. Both the drugs are equally effective in treating general symptoms such as somatic concern, anxiety, guilt feelings, tension, mannerisms and posturing, depression, motor retardation, uncooperativeness, unusual thought content, disorientation, poor attention, lack of judgment and insight, disturbance of volition, poor impulse control, preoccupation, and active social avoidance.

Risperidone is a relatively expensive antipsychotic. Treatment for 1 yearcosts approximately Rs. 3000-4000 for risperidone (6 mg/day) and Rs. 700-1000 (400 mg/day) for chlorpromazine.

Although risperidone is an expensive drug, dropouts were less in this group; this indicates a better effect of risperidone as compared with chlorpromazine. In this study, the cost of the drug did not influence the treatment by the drugs.

The dropouts in the risperidone group were less in comparison to those in the chlorpromazine group. This indicates compliance is better with the risperidone group compared with the chlorpromazine group.

In our study the age of the patient varied from 16 to 72 years. This suggests that the disease is prevalent in all age groups.

The distribution of the disease in our study has been observed almost equal in males and females. This is an agreement with the previous study by Castle et al., as they have also shown the equal ratio in distribution of schizophrenia.

Our study is in agreement with the study by Rabinowitz et al., who compared the effects of haloperidol (typical antipsychotic) and risperidone (atypical antipsychotic) on positive and negative symptoms in patients of schizophrenia by using PANSS and observed that patients receiving risperidone (4 mg) improved significantly more than those treated with haloperidol (10 mg). Although in our study, the effects were compared between chlorpromazine (100–1000 mg) and risperidone (3–16 mg) drugs.

However, in another similar comparative study between haloperidol and risperidone, Schooler et al. did not notice any significant difference in the improvement of positive and negative symptoms in patients of schizophrenia.

Another study was conducted by Sanger et al.; for the reduction of positive and negative symptoms of schizophrenia by using atypical antipsychotic (risperidone) and typical antipsychotic (haloperidol). Our study is also in agreement with the above study for negative symptoms, where a higher reduction in symptoms was reported for risperidone in comparison to chlorpromazine. However, the reduction in positive symptoms was found to be equal, i.e., approximately 70% for both the drugs.

Lieberman et al. had also shown the higher reduction in symptoms for atypical antipsychotic (clozapine reduction in symptoms 71%) than typical antipsychotic (chlorpromazine reduction in symptoms 64%).

Kennedy et al. in their study on cost-effectiveness and compliance reported that the conventional antipsychotic drugs such as haloperidol and chlorpromazine are frequently used as the first-line treatment in schizophrenia even after their poor response. This is because of the cost of the drugs, which also increases the compliance.

This is in contrast with our study where we have shown that the dropouts were less in the risperidone group than in the chlorpromazine group even though the cost of risperidone was high; this might be contributing to the better response of risperidone.

All these above studies clearly suggest the superiority of atypical antipsychotic drugs over the typical one, in terms of not only better efficacy in treating both positive and negative symptoms of schizophrenia but also decrease in side effects. Nevertheless, the role of typical antipsychotics cannot be ignored for the management on positive symptoms of schizophrenia and cost-effectivity when compared with the newer atypical group of antipsychotics.

The dropout rate is as high as 30% in patients of schizophrenia. The commonest reason for dropout in our study is poor response to the drug. The dropout rate is 75% for chlorpromazine and 25% for risperidone from the total dropouts because of nonresponsiveness to the drugs. The dropouts from the risperidone group were less in comparison to those from the chlorpromazine group. This indicates compliance is better with the risperidone group than with the chlorpromazine group. Schizophrenia is widely distributed in all age groups, and there was equal distribution of the disease in males and females. Both chlorpromazine and risperidone can effectively treat positive symptoms of schizophrenia.

Risperidone is superior to chlorpromazine in terms of treating negative symptoms of schizophrenia. Both drugs take good care of general symptoms of schizophrenia.

As chlorpromazine is relatively cheaper than risperidone, it should be preferred in patients with predominant positive symptoms and problem of poor affordability due to economical conditions, which is common in patients of schizophrenia due to regression of work performance, leading to hampering of economic conditions.

Risperidone should be preferred in patients with both positive and negative symptoms or patients with predominate negative symptoms.

What is it used for?

  • Psychotic illness such as schizophrenia.
  • Mania and hypomania.
  • Short-term treatment of severe anxiety.
  • Short-term treatment of severely agitated or excited behaviour and violent or dangerously impulsive behaviour.
  • Childhood autism.
  • Childhood schizophrenia.
  • Nausea and vomiting in terminal illness (when other medicines are ineffective).
  • Persistant hiccups.

How does it work?

Chlorpromazine is a type of medicine called a phenothiazine antipsychotic. It is used in the treatment of various psychiatric illnesses and is also used in the management of nausea and vomiting associated with terminal illness.

When used in psychiatric illness, chlorpromazine is sometimes described as a neuroleptic or a ‘major tranquilliser’, though this last term is fairly misleading, as this type of medicine is not just a tranquilliser and any tranquillising effect is not as important as the main way it works in psychiatric illness.

Chlorpromazine works by blocking a variety of receptors in the brain, particularly dopamine receptors. Dopamine is a natural compound called a neurotransmitter and is involved in transmitting messages between brain cells. Dopamine is a neurotransmitter known to be involved in regulating mood and behaviour, amongst other things.

Psychotic illness, in particular schizophrenia, is considered to be caused by overactivity of dopamine in the brain. Chlorpromazine blocks the receptors that dopamine acts on and this prevents the overactivity of dopamine in the brain. This helps to control psychotic illness.

Chlorpromazine improves disturbed thoughts, feelings and behaviour in various mental conditions, including schizophrenia, mania, and behavioural disorders that involve aggression or severe agitation or excitement. It produces a calming effect and controls aggression, delusions and hallucinations.

Chlorpromazine is used used in the long-term management of psychotic conditions such as schizophrenia. It is also used in the short-term to manage severe anxiety and severely agitated, violent or dangerous behaviour.

Chlorpromazine also affects dopamine receptors in an area of the brain that controls nausea and vomiting. Vomiting is controlled by an area of the brain called the vomiting centre. The vomiting centre is responsible for causing feelings of sickness (nausea) and for the vomiting reflex. It is activated when it receives nerve messages from another area of the brain called the chemoreceptor trigger zone (CTZ) and when it receives nerve messages from the gut.

Chlorpromazine controls nausea and vomiting by blocking dopamine receptors found in the CTZ. This stops the CTZ from sending the messages to the vomiting centre that would otherwise cause nausea and vomiting. Chlorpromazine is sometimes used to provide relief from nausea and vomiting in terminal illness, when other available medicines have been unsuccessful.

Chlorpromazine is also effective in treating persistant hiccups, though how it works in this case is unclear.

How do I take it?

  • Chlorpromazine tablets and oral solution can be taken either with or without food.
  • The dose of this medicine that is prescribed and how often it needs to be taken depends on the condition being treated. It is important to follow the instructions given by your doctor. These will be printed on the dispensing label that your pharmacist has put on the medicine.
  • If you forget to take a dose take it as soon as you remember, unless it is nearly time for your next dose. In this case just leave out the forgotten dose and take the next dose as usual. Don’t take a double dose to make up for a missed dose.
  • If you have been taking high doses of this medicine for a long time, for example to treat schizophrenia, you should not suddenly stop taking it unless your doctor tells you to, even if you feel better and think you don’t need it any more. This is because the medicine controls the symptoms of the illness but doesn’t actually cure it. This means that if you suddenly stop treatment your symptoms could come back. Stopping the medicine suddenly may also rarely cause withdrawal symptoms such as nausea, vomiting, difficulty sleeping or tremor. When long-term treatment with this medicine is stopped, it should be done gradually, following the instructions given by your doctor.


  • This medicine may cause drowsiness. If affected do not drive or operate machinery. You should avoid drinking alcohol while taking this medicine because it can make drowsiness worse.
  • This medicine can occasionally cause your blood pressure to drop when you move from a lying down or sitting position to sitting or standing, especially when you first start taking the medicine, or if you are elderly. This may make you feel dizzy or unsteady. To avoid this try getting up slowly. If you do feel dizzy, sit or lie down until the symptoms pass.
  • High doses of this medicine may make your skin more sensitive to sunlight than it usually is, so you should avoid exposing your skin to direct sunlight or sunlamps until you know how your skin reacts. If you can’t avoid sunlight you should use a sunscreen lotion or make sure your skin is protected with clothing.
  • Chlorpromazine can cause rare but serious contact skin sensitisation in people who regularly handle the medicine. For this reason chlorpromazine tablets should not be broken or crushed and you should avoid any unnecessary contact of the tablets with the skin.
  • It is recommended that you have regular eye examinations if you are taking this medicine for long periods of time, as it can sometimes cause eye problems. Consult your doctor if you experience any disturbances in your vision while taking this medicine.
  • Antipsychotic medicines are associated with an increased risk of getting a blood clot in a vein (deep vein thrombosis) or in the lungs (pulmonary embolism). For this reason, you should consult a doctor immediately if you get any of the following symptoms, which could suggest you have a blood clot: stabbing pains and/or unusual redness or swelling in one leg, pain on breathing or coughing, coughing up blood or sudden breathlessness.
  • Antipsychotic medicines can sometimes affect the ability of the body to control its core body temperature. This is more likely to be a problem in elderly people and can result in heat stroke in hot temperatures and hypothermia in cold temperatures. It is important to avoid situations that can result in you overheating or getting dehydrated. Ask your doctor or pharmacist for more advice.
  • This medicine may rarely cause a decrease in the normal amounts of blood cells in the blood. For this reason you should consult your doctor immediately if you experience any of the following symptoms: unexplained bruising or bleeding, purple spots, sore throat, mouth ulcers, high temperature (fever), feeling tired or general illness. Your doctor may want to take a blood test to check your blood cells.
  • Consult your doctor immediately if you experience abnormal body movements, particularly of the face, lips, jaw and tongue, while taking this medicine. These symptoms may be indicative of a rare side effect known as tardive dyskinesia, and your doctor may ask you to stop taking this medicine, or decrease your dose.
  • Consult your doctor immediately if you experience the following symptoms while taking this medicine: high fever, sweating, muscle stiffness, faster breathing and drowsiness or sleepiness. These symptoms may be due to a rare side effect known as the neuroleptic malignant syndrome, and your treatment may need to be stopped.

Use with caution in

  • Elderly people.
  • Decreased kidney function.
  • Decreased liver function.
  • Elderly people with dementia. (Antipsychotic medicines have been shown to increase the risk of stroke in this group of patients. Chlorpromazine is not licensed or recommended for treating behavioural disturbances in elderly people with dementia).
  • Severe disease affecting the airways or lungs.
  • Heart disease, such as heart failure, recent heart attack, very slow heart rate (bradycardia) or irregular heart beats (arrhythmias).
  • People with a personal or family history of a type of abnormal heart rhythm, seen on a heart monitoring trace (ECG) as a ‘prolonged QT interval’.
  • People with low levels of potassium or magnesium in their blood (hypokalaemia or hypomagnesaemia).
  • People with low fluid volume in their body, eg due to diuretic therapy, kidney dialysis, diarrhoea, vomiting, dehydration.
  • People with risk factors for having a stroke, for example a history of stroke or mini-stroke (TIA), smoking, diabetes, high blood pressure, or a type of irregular heartbeat called atrial fibrillation.
  • People with a personal or family history of blood clots (venous thromboembolism), for example in a vein of the leg (deep vein thrombosis) or in the lungs (pulmonary embolism).
  • People with other risk factors for getting a blood clot, for example smoking, being overweight, taking the contraceptive pill, being over 40, recent major surgery or being immobile for prolonged periods.
  • Diabetes. People with diabetes should monitor their blood sugar levels more closely whilst taking this medicine. This medicine may increase the blood sugar levels in the body.
  • Epilepsy.
  • People with conditions that increase the risk of epilepsy or convulsions, eg brain damage or withdrawal from alcohol.
  • Parkinson’s disease.
  • Abnormal muscle weakness (myasthenia gravis).
  • People with a history of closed angle glaucoma.
  • Men with an enlarged prostate gland (prostatic hypertrophy).
  • Underactive thyroid gland (hypothyroidism).
  • Tumour of the adrenal gland (phaeochromocytoma).
  • People who are allergic to other phenothiazine medicines, such as prochlorperazine or trifluoperazine.

Not to be used in

  • People in unresponsive unconscious states (comatose states).
  • People with reduced awareness, slow reactions or drowsiness due to medicines or illness that reduce activity in the central nervous system.
  • Severe disease involving the heart and blood vessels (cardiovascular disease).
  • People with a history of a drop in the normal number of blood cells in the blood.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • The safety of this medicine during pregnancy has not been established. It should not be used in pregnancy, particularly in the first and third trimesters, unless considered essential by your doctor. If the medicine is used during the third trimester it could cause side effects or withdrawal symptoms in the baby after birth and the baby may need extra monitoring because of this. Seek further medical advice from your doctor.
  • If you do get pregnant while taking this medicine it is important to consult your doctor straight away for advice. If you have been taking the medicine for long periods of time, for instance to treat schizophrenia, you should not suddenly stop taking it unless your doctor tells you to, as this could cause your symptoms to come back.
  • This medicine may pass into breast milk. As it could cause drowsiness and potentially other side effects in a nursing infant, it is recommended that women who need treatment with this medicine should not breastfeed. Seek further medical advice from your doctor.

Label warnings

  • This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.
  • Avoid exposure of skin to direct sunlight or sun lamps.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.

  • Drowsiness.
  • Abnormal movements of the hands, legs, face, neck and tongue, eg tremor, twitching, rigidity (extrapyramidal effects, dyskinesia or dystonia).
  • Anxiety, restlessness and agitation (akathisia).
  • A drop in blood pressure that occurs when moving from a lying down or sitting position to sitting or standing, which results in dizziness and lightheadedness (postural hypotension – see warning section above).
  • Dry mouth.
  • Blocked nose.
  • Difficulty sleeping (insomnia).
  • Nightmares.
  • High blood prolactin (milk producing hormone) level (hyperprolactinaemia). Sometimes this may lead to symptoms such as breast enlargement, production of milk, stopping of periods or problems getting an erection.
  • Weight gain.
  • Abnormal heart beats (arrhythmias).
  • Jaundice (tell your doctor straight away if you notice any yellowing of your eyes or skin while taking this medicine).
  • Skin rashes.
  • Increased sensitivity of the skin to UV light (photosensitivity – see warning section above).
  • Metallic grey/mauve discolouration of the skin and parts of the eyes.
  • Clouding of the lens or cornea in the eyes.
  • Increased blood glucose levels. Tell your doctor if you notice you feel unusually hungry or thirsty, or need to pass urine more often than usual. People with diabetes should monitor their blood sugar closely.
  • Decrease in the number of white blood cells in the blood (leucopenia – see warning section above).
  • Interference with the body’s temperature regulation (this is more common in elderly people and may cause heat stroke in very hot weather or hypothermia in very cold weather).
  • Rhythmical involuntary movement of the tongue, face, mouth and jaw, which may sometimes be accompanied by involuntary movements of the arms and legs (tardive dyskinesia). See warning section above.
  • High temperature combined with falling levels of consciousness, paleness, sweating and a fast heart beat (neuroleptic malignant syndrome). Requires stopping the medicine and immediate medical treatment – see warning section above.
  • Convulsions.
  • Abnormal blood clot in the blood vessels (venous thromboembolism – see warning section above).

The side effects listed above may not include all of the side effects reported by the medicine’s manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.

There may be an increased risk of drowsiness and sedation if chlorpromazine is taken with any of the following, which can also cause drowsiness:

  • alcohol
  • barbiturates, eg amobarbital, phenobarbital
  • benzodiazepines, eg diazepam, temazepam
  • MAOI antidepressants, eg phenelzine
  • sedating antihistamines, eg chlorphenamine, hydroxyzine
  • sleeping tablets, eg zopiclone
  • strong opioid painkillers, eg morphine, codeine
  • tricyclic antidepressants, eg amitriptyline.

There may be an increase in side effects such as dry mouth, constipation, confusion or heat stroke (in hot and humid conditions) if chlorpromazine is taken with other medicines that have anticholinergic effects, including the following:

  • anticholinergic medicines for Parkinson’s symptoms, eg procyclidine
  • antihistamines, eg brompheniramine, chlorphenamine
  • other antipsychotic medicines
  • other antisickness medicines, eg promethazine, meclozine, cyclizine
  • antispasmodic medicines, eg hyoscine
  • MAOI antidepressants, eg phenelzine
  • medicines for urinary incontinence, eg oxybutynin, flavoxate, tolterodine, propiverine, trospium
  • muscle relaxants, eg baclofen
  • tricyclic antidepressants, eg amitriptyline.

Anticholinergic medicines such as procyclidine, which are sometimes used to treat the Parkinson-like side effects of chlorpromazine, may oppose the antipsychotic effect of this medicine.

Chlorpromazine may enhance the blood pressure-lowering effects of medicines that lower blood pressure, including medicines used to treat high blood pressure (antihypertensives) and medicines that lower blood pressure as a side effect, eg benzodiazepines. If you are taking medicines that lower blood pressure you should tell your doctor if you feel dizzy or faint after starting treatment with this medicine, as your doses may need adjusting.

Medicines that increase the risk of a type of abnormal heart rhythm, seen as a ‘prolonged QT interval’ on an ECG, should be avoided in combination with chlorpromazine. These medicines include the following:

  • antiarrhythmics (medicines to treat abnormal heart beats), eg amiodarone, procainamide, disopyramide, sotalol
  • the antihistamines astemizole, mizolastine or terfenadine
  • arsenic trioxide
  • atomoxetine
  • certain antidepressants, eg amitriptyline, imipramine, maprotiline
  • certain antimalarials, eg halofantrine, chloroquine, quinine, mefloquine, Riamet
  • certain antipsychotics, eg thioridazine, pimozide, sertindole , haloperidol
  • cisapride
  • dronedarone
  • droperidol
  • intravenous erythromycin or pentamidine
  • methadone
  • moxifloxacin
  • saquinavir.

There may also be an increased risk of a prolonged QT interval if medicines that can alter the levels of salts such as potassium or magnesium in the blood, eg diuretics such as furosemide, are taken in combination with chlorpromazine.

There may be an increased risk of a drop in the number of white blood cells in the blood if chlorpromazine is taken in combination with other medicines that can have this side effect, such as the following:

  • anti-cancer chemotherapy medicines
  • carbamazepine
  • co-trimoxazole
  • penicillamine
  • phenylbutazone
  • sulphonamides, eg sulfadiazine.

Chlorpromazine may oppose the effect of anticonvulsant medicines used to treat epilepsy.

Chlorpromazine may increase blood sugar levels and disturb the control of diabetes. People with diabetes may need an adjustment in the dose of their antidiabetic medication.

Chlorpromazine may oppose the effects of dopamine agonists used to treat Parkinson’s disease, eg levodopa, apomorphine, bromocriptine, cabergoline, pergolide, ropinirole, rotigotine.

Chlorpromazine may oppose the effect of histamine (used to treat leukaemia) and is not recommended for people having this treatment.

If chlorpromazine is used in combination with propranolol the breakdown of both medicines by the liver may decrease, resulting in increased levels of both medicines in the blood. This could increase the risk of side effects of both medicines.

Cimetidine may enhance or reduce the effect of chlorpromazine.

Phenobarbital may increase the breakdown of chlorpromazine by the liver and so could make it less effective.

Lithium may lower the amount of chlorpromazine in the blood and could make it less effective. There may also be an increased risk of extrapyramidal side effects (abnormal body movements) with this combination.

Antacids for indigestion may potentially reduce the absorption of this medicine from the gut and so could make it less effective. To avoid a possible interaction, you should avoid taking antacids within two to three hours of taking this medicine.

Other medicines containing the same active ingredient

Largactil injection

Chlorpromazine is available generically as tablets, oral solution, suppositories and injection.

Last updated 13.08.2012


Note: Some adverse effects of Thorazine (chlorpromazine) may be more likely to occur, or occur with greater intensity, in patients with special medical problems, e.g., patients with mitral insufficiency or pheochromocytoma have experienced severe hypotension following recommended doses.

Drowsiness, usually mild to moderate, may occur, particularly during the first or second week, after which it generally disappears. If troublesome, dosage may be lowered.

B Overall incidence has been low, regardless of indication or dosage. Most investigators conclude it is a sensitivity reaction. Most cases occur between the second and fourth weeks of therapy. The clinical picture resembles infectious hepatitis, with laboratory features of obstructive jaundice, rather than those of parenchymal damage. It is usually promptly reversible on withdrawal of the medication; however, chronic jaundice has been reported.

There is no conclusive evidence that preexisting liver disease makes patients more susceptible to jaundice. Alcoholics with cirrhosis have been successfully treated with Thorazine (chlorpromazine) without complications. Nevertheless, the medication should be used cautiously in patients with liver disease. Patients who have experienced jaundice with a phenothiazine should not, if possible, be reexposed to Thorazine (chlorpromazine) or other phenothiazines.

If fever with grippe-like symptoms occurs, appropriate liver studies should be conducted. If tests indicate an abnormality, stop treatment.

Liver function tests in jaundice induced by the drug may mimic extrahepatic obstruction; withhold exploratory laparotomy until extrahepatic obstruction is confirmed.

Hematological Disorders, including agranulocytosis, eosinophilia, leukopenia, hemolytic anemia, aplastic anemia, thrombocytopenic purpura and pancytopenia have been reported.

Agranulocytosis — Warn patients to report the sudden appearance of sore throat or other signs of infection. If white blood cell and differential counts indicate cellular depression, stop treatment and start antibiotic and other suitable therapy.

Most cases have occurred between the fourth and tenth weeks of therapy; patients should be watched closely during that period.

Moderate suppression of white blood cells is not an indication for stopping treatment unless accompanied by the symptoms described above.


Hypotensive Effects — Postural hypotension, simple tachycardia, momentary fainting and dizziness may occur after the first injection; occasionally after subsequent injections; rarely, after the first oral dose. Usually recovery is spontaneous and symptoms disappear within 1 / 2 to 2 hours. Occasionally, these effects may be more severe and prolonged, producing a shock-like condition.

To minimize hypotension after injection, keep patient lying down and observe for at least 1 / 2 hour. To control hypotension, place patient in head-low position with legs raised. If a vasoconstrictor is required, Levophed® *** and Neo-Synephrine® § are the most suitable. Other pressor agents, including epinephrine, should not be used as they may cause a paradoxical further lowering of blood pressure.

EKG Changes — particularly nonspecific, usually reversible Q and T wave distortions— have been observed in some patients receiving phenothiazine tranquilizers, including Thorazine (chlorpromazine).

Note: Sudden death, apparently due to cardiac arrest, has been reported.

CNS Reactions

Neuromuscular (Extrapyramidal) Reactions — Neuromuscular reactions include dystonias, motor restlessness, pseudo-parkinsonism and tardive dyskinesia, and appear to be dose-related. They are discussed in the following paragraphs:

Dystonias: Symptoms may include spasm of the neck muscles, sometimes progressing to acute, reversible torticollis; extensor rigidity of back muscles, sometimes progressing to opisthotonos; carpopedal spasm, trismus, swallowing difficulty, oculogyric crisis and protrusion of the tongue.

These usually subside within a few hours, and almost always within 24 to 48 hours after the drug has been discontinued.

In mild cases, reassurance or a barbiturate is often sufficient. In moderate cases, barbiturates will usually bring rapid relief. In more severe adult cases, the administration of an anti-parkinsonism agent, except levodopa, usually produces rapid reversal of symptoms. In children (1 to 12 years of age), reassurance and barbiturates will usually control symptoms. (Or, parenteral Benadryl® ll may be useful. See Benadryl prescribing information for appropriate children’s dosage.) If appropriate treatment with anti-parkinsonism agents or Benadryl fails to reverse the signs and symptoms, the diagnosis should be reevaluated.

Suitable supportive measures such as maintaining a clear airway and adequate hydration should be employed when needed. If therapy is reinstituted, it should be at a lower dosage. Should these symptoms occur in children or pregnant patients, the drug should not be reinstituted.

Motor Restlessness: Symptoms may include agitation or jitteriness and sometimes insomnia. These symptoms often disappear spontaneously. At times these symptoms may be similar to the original neurotic or psychotic symptoms. Dosage should not be increased until these side effects have subsided.

If these symptoms become too troublesome, they can usually be controlled by a reduction of dosage or change of drug. Treatment with anti-parkinsonian agents, benzodiazepines or propranolol may be helpful.

Pseudo-parkinsonism: Symptoms may include: mask-like facies, drooling, tremors, pillrolling motion, cogwheel rigidity and shuffling gait. In most cases these symptoms are readily controlled when an anti-parkinsonism agent is administered concomitantly. Anti-parkinsonism agents should be used only when required. Generally, therapy of a few weeks to 2 or 3 months will suffice. After this time patients should be evaluated to determine their need for continued treatment. (Note: Levodopa has not been found effective in antipsychotic-induced pseudo-parkinsonism.) Occasionally it is necessary to lower the dosage of Thorazine (chlorpromazine) or to discontinue the drug.

Tardive Dyskinesia: As with all antipsychotic agents, tardive dyskinesia may appear in some patients on long-term therapy or may appear after drug therapy has been discontinued. The syndrome can also develop, although much less frequently, after relatively brief treatment periods at low doses. This syndrome appears in all age groups. Although its prevalence appears to be highest among elderly patients, especially elderly women, it is impossible to rely upon prevalence estimates to predict at the inception of antipsychotic treatment which patients are likely to develop the syndrome. The symptoms are persistent and in some patients appear to be irreversible. The syndrome is characterized by rhythmical involuntary movements of the tongue, face, mouth or jaw (e.g., protrusion of tongue, puffing of cheeks, puckering of mouth, chewing movements). Sometimes these may be accompanied by involuntary movements of extremities. In rare instances, these involuntary movements of the extremities are the only manifestations of tardive dyskinesia. A variant of tardive dyskinesia, tardive dystonia, has also been described.

There is no known effective treatment for tardive dyskinesia; anti-parkinsonism agents do not alleviate the symptoms of this syndrome. If clinically feasible, it is suggested that all antipsychotic agents be discontinued if these symptoms appear. Should it be necessary to reinstitute treatment, or increase the dosage of the agent, or switch to a different antipsychotic agent, the syndrome may be masked.

It has been reported that fine vermicular movements of the tongue may be an early sign of the syndrome and if the medication is stopped at that time the syndrome may not develop.

Adverse Behavioral Effects — Psychotic symptoms and catatonic-like states have been reported rarely.

Other CNS Effects— Neuroleptic Malignant Syndrome (NMS) has been reported in association with antipsychotic drugs. (See WARNINGS.) Cerebral edema has been reported.

Convulsive seizures (petit mal and grand mal) have been reported, particularly in patients with EEG abnormalities or history of such disorders.

Abnormality of the cerebrospinal fluid proteins has also been reported.

Allergic Reactions of a mild urticarial type or photosensitivity are seen. Avoid undue exposure to sun. More severe reactions, including exfoliative dermatitis, have been reported occasionally.

Contact dermatitis has been reported in nursing personnel; accordingly, the use of rubber gloves when administering Thorazine (chlorpromazine) liquid or injectable is recommended.

In addition, asthma, laryngeal edema, angioneurotic edema and anaphylactoid reactions have been reported.

Endocrine Disorders: Lactation and moderate breast engorgement may occur in females on large doses. If persistent, lower dosage or withdraw drug. False-positive pregnancy tests have been reported, but are less likely to occur when a serum test is used. Amenorrhea and gynecomastia have also been reported. Hyperglycemia, hypoglycemia and glycosuria have been reported.

Autonomic Reactions: Occasional dry mouth; nasal congestion; nausea; obstipation; constipation; adynamic ileus; urinary retention; priapism; miosis and mydriasis, atonic colon, ejaculatory disorders/impotence.

Special Considerations in Long-Term Therapy: Skin pigmentation and ocular changes have occurred in some patients taking substantial doses of Thorazine (chlorpromazine) for prolonged periods.

Skin Pigmentation — Rare instances of skin pigmentation have been observed in hospitalized mental patients, primarily females who have received the drug usually for 3 years or more in dosages ranging from 500 mg to 1500 mg daily. The pigmentary changes, restricted to exposed areas of the body, range from an almost imperceptible darkening of the skin to a slate gray color, sometimes with a violet hue. Histological examination reveals a pigment, chiefly in the dermis, which is probably a melanin-like complex. The pigmentation may fade following discontinuance of the drug.

Ocular Changes — Ocular changes have occurred more frequently than skin pigmentation and have been observed both in pigmented and nonpigmented patients receiving Thorazine (chlorpromazine) usually for 2 years or more in dosages of 300 mg daily and higher. Eye changes are characterized by deposition of fine particulate matter in the lens and cornea. In more advanced cases, star-shaped opacities have also been observed in the anterior portion of the lens. The nature of the eye deposits has not yet been determined. A small number of patients with more severe ocular changes have had some visual impairment. In addition to these corneal and lenticular changes, epithelial keratopathy and pigmentary retinopathy have been reported. Reports suggest that the eye lesions may regress after withdrawal of the drug.

Since the occurrence of eye changes seems to be related to dosage levels and/or duration of therapy, it is suggested that long-term patients on moderate to high dosage levels have periodic ocular examinations.

Etiology — The etiology of both of these reactions is not clear, but exposure to light, along with dosage/duration of therapy, appears to be the most significant factor. If either of these reactions is observed, the physician should weigh the benefits of continued therapy against the possible risks and, on the merits of the individual case, determine whether or not to continue present therapy, lower the dosage, or withdraw the drug.

Other Adverse Reactions: Mild fever may occur after large I.M. doses. Hyperpyrexia has been reported. Increases in appetite and weight sometimes occur. Peripheral edema and a systemic lupus erythematosus-like syndrome have been reported.

Note: There have been occasional reports of sudden death in patients receiving phenothiazines. In some cases, the cause appeared to be cardiac arrest or asphyxia due to failure of the cough reflex.


No information provided.

Thorazine (chlorpromazine) is an injection medication that may be prescribed off-label to help manage movement disorders such as chorea in people with Huntington’s disease.

How Thorazine works

Thorazine is a type of antipsychotic therapy, called a phenothiazine. It was developed in the 1950s to treat mental disorders such as schizophrenia.

Mental disorders can be caused by the overactivation of the dopamine system in the brain. Dopamine is a type of chemical messenger, called a neurotransmitter, which carries signals between nerve cells. When dopamine is released by a nerve cell, it binds to and activates a receptor found on the adjacent nerve cell to transmit the signal.

Dopamine acts in several areas of the brain and has multiple roles, including the regulation of mood and the control of movement. Chorea, the involuntary movements associated with Huntington’s disease, can be caused by an inappropriate activation of dopaminergic neurons.

Thorazine is an antagonist of several neurotransmitter receptors, including dopamine. By binding to the receptor in the place of dopamine, it prevents dopamine from accessing the receptor to block the transmission of the signal. Ultimately, this should reduce overactivation of nerves controlling movement, and ease the symptoms of chorea.

Additional information

Thorazine may significantly reduce the action of dopamine, causing such Parkinson’s disease-like symptoms as muscle rigidity, tremors, and slowed movement. Additional effects may include dystonia (muscle spasms or contractions), akathisia (restless legs syndrome), and dyskinesia (involuntary movements).

Commonly reported side effects of Thorazine can include drowsiness, dizziness, skin reactions (such as rashes), dry mouth, orthostatic hypotension (low blood pressure when getting up from a sitting or lying position), amenorrhea (missed menstrual periods), galactorrhea (milky discharge from the nipples), and weight gain.

Thorazine is classed as a first-generation antipsychotic and has been used to treat schizophrenia and other conditions since the 1950s. No clinical trials have specifically assessed its effectiveness in Huntington’s patients.

Thorazine may be prescribed off-label for Huntington’s disease. This means that while it may have beneficial effects, it is not specifically approved for Huntington’s by regulatory bodies, such as the U.S. Food and Drug Administration (FDA).


Huntington’s Disease News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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