- About prazosin
- Before taking prazosin
- How to take prazosin
- Getting the most from your treatment
- Can prazosin cause problems?
- How to store prazosin
- Important information about all medicines
- Article Highlights
- Availability and Dosages of Prazosin
- Generic Versus Brand Names of Prazosin
- Use, Route, and Dosage of Prazosin
- Benign Prostatic Hyperplasia
- Post-Traumatic Stress Disorder (PTSD) and Related Sleep Disruptions
- Raynauds’ Phenomenon
- Prazosin and Alzheimer’s Disease
- Instructions for Taking Prazosin
- Desired Effect of Prazosin
- Adverse Reactions and Side Effects of Prazosin
- Drug Interactions with Prazosin
- Final Thoughts
- Further information
- More about prazosin
- Prazosin doesn’t alleviate distressing dreams in PTSD
|Type of medicine||An alpha-blocker|
|Used for||High blood pressure; heart failure; enlargement of the prostate gland in men; Raynaud’s syndrome|
Prazosin belongs to a group of medicines known as alpha-blockers. It works by blocking the action of certain nerve impulses. This blocking action is useful in a variety of different medical conditions which are listed in the table above, although it is usually used to treat high blood pressure (hypertension).
Prazosin works in people with high blood pressure or with heart failure, by relaxing blood vessels. This allows blood and oxygen to circulate more freely around your body, lowering blood pressure and reducing strain on your heart.
The prostate gland commonly becomes larger in older men. Prostate gland enlargement is also called benign prostatic hyperplasia (BPH). The prostate gland is situated close to the bladder, so its enlargement can cause problems with passing urine. Common symptoms that are experienced are having to wait before your urine starts to flow, taking longer at the toilet, dribbling urine, and a feeling that your bladder is not quite empty. Prazosin works by relaxing the muscles around your bladder and prostate gland so that you can pass urine more easily.
In Raynaud’s disease, prazosin relaxes the blood vessels in your hands so that blood can reach your fingers more easily. This helps to prevent coldness and stiffness.
Before taking prazosin
Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking prazosin it is important that your doctor knows:
- If you ever feel dizzy or faint when you stand up, or if you have ever fainted after passing urine.
- If you need to have cataract eye surgery.
- If you are pregnant or breastfeeding.
- If you have any problems with the way your liver works, or any problems with the way your kidneys work.
- If you have ever had an allergic reaction to a medicine.
- If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
How to take prazosin
- Before you start the treatment, read the manufacturer’s printed information leaflet from inside the pack. It will give you more information about prazosin and will provide you with a full list of the side-effects which you may experience from taking it.
- Your doctor will tell you how many tablets to take each day. This can range from 2-4 tablets a day depending upon the reason why you have been prescribed prazosin. Take the tablets exactly as your doctor tells you to.
- Swallow the tablet with a drink of water. You can take prazosin either before or after a meal, but you should try to take your doses at the same times of day each day. This will help you to remember to take the tablets regularly.
- Your first dose of prazosin may make you feel dizzy or faint, so it is important that you take it just before you go to bed. If you feel dizzy or weary, or if you start sweating, remain lying down until these symptoms have completely gone.
- There are several strengths of prazosin tablet available: 500 micrograms, 1 mg, 2 mg, and 5 mg. When you first start the treatment, your doctor will give you a low dose which may then later be increased. This allows your doctor to make sure that you have the dose that helps your condition and avoids any unwanted symptoms.
- If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.
Getting the most from your treatment
- Prazosin can cause dizziness, particularly when you first start taking it. This may affect your ability to drive. Make sure your reactions are normal before you drive or do things which would be dangerous if you were not fully alert.
- Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. Your doctor is likely to want to take your blood pressure from time to time, particularly when you first start the treatment.
- You are advised not to drink alcohol while you are on prazosin. Alcohol increases the risk of side-effects from prazosin, such as feeling faint or dizzy.
- If you are taking prazosin for urinary symptoms, consider reducing or stopping the amount of caffeine you drink (commonly found in tea, coffee and cola). Caffeine can make your symptoms worse, so drinking less of these things may benefit you. Also, if you are a smoker, stopping smoking may significantly improve your symptoms. This is because nicotine irritates the bladder. You can ask your doctor for advice on quitting.
- If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking prazosin. This is because your blood pressure may drop suddenly if you have an anaesthetic. If you are having cataract surgery, it is particularly important that you tell your surgeon you are on prazosin. This is because an eye problem known as ‘floppy iris syndrome’ has developed in some people and your doctor may advise you to stop taking prazosin for a short while.
- If you buy any medicines check with a pharmacist that they are suitable to take with your other medicines. Some anti-inflammatory painkillers, called non-steroidal anti-inflammatory drugs (NSAIDs), can reduce the blood pressure-lowering effect of prazosin.
Can prazosin cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with prazosin. You will find a full list in the manufacturer’s information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
|Common prazosin side-effects (these affect less than 1 in 10 people)||What can I do if I experience this?|
|Feeling tired, dizzy, or faint; blurred vision||Do not drive and do not use tools or machines while affected|
|Feeling light-headed when getting up from a lying or sitting position||Getting up more slowly may help. If you begin to feel dizzy, lie down so that you do not faint, then sit for a few moments to prevent the dizziness returning|
|Constipation or diarrhoea, feeling sick||Eat a simple but well-balanced diet, and drink plenty of water|
|Headache||Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the headaches continue, let your doctor know|
|Feeling depressed or nervous, the sensation of having a ‘thumping heart’ (palpitations), blocked nose, dry mouth, rash, feeling short of breath, feeling the need to pass urine more frequently, swollen hands or feet||If any of these become troublesome, speak with your doctor|
If you experience any other symptoms which you think may be due to the tablets, speak with your doctor or pharmacist for further advice.
How to store prazosin
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.
This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
If you have any questions about this medicine ask your pharmacist.
- Prazosin is a high blood pressure medication that comes in 1 mg, 2 mg and 5 mg capsules. Adults can take Prazosin by mouth, in 1 mg dosage, up to 3 times daily.
- Prazosin is also used to treat benign prostatic hyperplasia, post-traumatic stress disorder, Raynaud’s syndrome and Alzheimer’s disease.
- Prazosin has shown promise in helping with Alzheimer’s-related aggressive agitation.
- Side effects of Prazosin include reactions of central nervous system, respiratory system, cardiovascular system, etc.
- It is important that the patient’s healthcare provider is aware of all of the meds that are being taken as some medications can interact with Prazosin.
- Older adults require a lower dose because Prazosin may cause significant hypotension.
- A person taking Prazosin should change positions slowly if he or she experiences dizziness. If this does not work, the healthcare provider should be notified immediately.
Prazosin is a medication that is used to treat high blood pressure. Prazosin is classified as an antihypertensive, and it can be given alone or in combination with other medications. Prazosin lowers a person’s blood pressure and decreases the risk of cardiovascular events such as heart attack or stroke.
This article covers Prazosin, how it is used, the conditions it is used to treat, and the side effects a person taking this medication may experience. As this article is only meant to provide the reader with general knowledge about the medication and its most common uses, there may well be various other conditions for which Prazosin is prescribed that are not covered in this article.
Availability and Dosages of Prazosin
Prazosin is available as both a generic and a brand name medicine. Prazosin was approved by the Food and Drug Administration (FDA) in 1976, and there are a number of different brand names for this medication including:
The medication comes in 1 mg, 2 mg and 5 mg capsules, and the capsules may be white, pink and white or blue and white, depending on the manufacturer. To ensure that you are using the right medication and dosage, it is always best to check with your pharmacy as they may have changed manufacturers.
Generic Versus Brand Names of Prazosin
If you are wondering if you should take the generic or brand name product, please continue reading. When a generic product is approved by the Food and Drug Administration (FDA), it means that the drug has met the standards of strength, quality, purity and potency, as set by the FDA.
Generic drugs are required to have the same active ingredient, strength, dosage form, and administration route as brand name medications. Generic drug manufacturers are required to pass the same quality standards as brand name drug manufacturers, and research has shown that generic drugs work just as well their brand name medications. The one big difference between brand name and generic drugs is price, with generic drugs on average costing 80 to 85 percent less than the brand name product.
Use, Route, and Dosage of Prazosin
Adults can take this medication by mouth, usually in 1 mg dosage, up to 3 times daily. It is recommended that the first dose of the medication be taken at bedtime. This medication may also be used in children for the treatment of hypertension, and the dose is individualized based on the weight of the child.
Wendy: No medicine could lower my blood pressure from approximately 145/ 90, though Prazosin did it. Now my blood pressure is normal with a systolic pressure of 125 or less, and diastolic pressure of 65 or less. This is absolutely fantastic, and I still can’t believe it despite taking measurements regularly. I have side effects occasionally, like light headedness, and I may at times be a little weak or a little shaky. Note I only take a half tablet in the morning and a half tablet at night before I go to bed. Also, when the doctor prescribed Prazosin for me, I was taking two other blood pressure medications. After some adjustments made by my physician, I am now only taking Prazosin. My blood pressure is normal, and once I lost weight and stopped smoking, I started to feel fantastic. I continue to go to my scheduled appointments and get checked by my doctor, and I seem to be doing great. I would highly recommend Prazosin for blood pressure control, subject to your doctor agreeing and prescribing it for you. For me, it’s been an effective medication with very few side effects.
Benign Prostatic Hyperplasia
Men suffering with enlarged prostates are also prescribed Prazosin. However, it is recommended that a person be checked for cancer prior to being prescribed the medication. The medication is taken by mouth and the patient is given 1-5 mg up to twice daily.
Peter has benign prostatic hypertrophy (BPH). He describes how he had problems with urgency, urine dribbling, and frequent trips to the bathroom at night that prevented him from getting good sleep. He found it embarrassing when taking road trips with his family. He would have to plan his trips around the nearest bathroom. He now takes Prazosin 2 mg twice daily and is happy with the results. “It has worked wonders for me, and there have been no side effects.”
Post-Traumatic Stress Disorder (PTSD) and Related Sleep Disruptions
Post-traumatic Stress Disorder (PTSD) is a disabling anxiety that affects one in four Americans, as per 2011 Consumer Reports. Traumatic events such as military combat, abuse, violent physical or sexual assaults or accidents can trigger this disabling condition, and nearly 70 percent of people that have PTSD experience sleep difficulties. Prazosin is one of the treatment recommendations to alleviate this condition, for Prazosin blocks the body’s release of the hormone adrenaline. Current recommended dosage is 1 mg of Prazosin by mouth at bedtime.
Wilbur is a Gulf-War veteran. He has experienced PTSD for the last eighteen years. Wilbur describes experiencing nightmares related to his combat experience. The nightmares would be so bad that they would cause disabling anxiety the following day. He had been prescribed Restoril to help him sleep, and Valium and Xanax for anxiety, but these medications had no effect on the PTSD-related nightmares. Wilbur remembers discussing other possible options with his doctors, and he was skeptical when he heard about Prazosin. Now he has been using the medication for the past two years at bedtime. Wilbur is very pleased with the performance of the medication and finds it has a positive effect on the nightmares caused by PTSD.
Raynaud’s’ Phenomenon is a disorder that affects the blood vessels of fingers and toes. It causes the blood vessels to narrow when the person is cold or feeling stress, a known “fight or flight” response. People of all ages can have this disorder, and according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, it can run in families as well. This disorder is most common in women and people living in cold places. Prazosin may be prescribed for these individuals at 1-5 mg by mouth every 12 hours.
George’s story is interesting: prior to taking Prazosin for nightmares, he had a bad case of Raynaud’s syndrome. Once he started taking the medication for the nightmares, he also noticed an improvement in his fingers and toes with the Raynaud’s. He has been taking Prazosin for 5 years and has not had any issues with Raynaud’s. He did however build up a tolerance for the medication and had to be put on a different medication for the nightmares.
Prazosin and Alzheimer’s Disease
Alzheimer’s disease (AD), the most common form of dementia, is a progressive disease that takes away mental function, memory and the ability to perform daily tasks and care for oneself over time. Though there is no cure for AD, there are some medications that temporarily improve the symptoms that are associated with Alzheimer’s, helping a person with dementia maintain their independence for a longer period of time.
As Alzheimer’s disease progresses, individuals often experience agitation and aggression that can be difficult for individuals and their families to manage. This is also the reason why many people suffering with Alzheimer’s disease often end up in long term care facilities. In Alzheimer’s disease, the brain experiences serious shrinkage secondary to the buildup of plaques and tangles in the brain. Plaques are clumps of protein also known as beta-amyloids, and they destroy brain cells by blocking cell to cell communication. Tangles occur when tau proteins, normally in the brain, twist into abnormal shapes. Tau proteins are the brain’s transport system and require normal shape and structure in order to work properly.
Prazosin has shown promise in helping those experiencing Alzheimer’s-related aggressive agitation. Prazosin is a vasodilator and causes the smooth muscles to relax by blocking alpha one adrenergic receptors. This is important because in Alzheimer’s, the alpha one adrenergic receptors degenerate, which can lead to changes in arousal, mood and memory.
The use of Prazosin for agitation secondary to Alzheimer’s has shown promise and is still being tested by the Alzheimer’s Disease Cooperative Study, with funding from the National Institutes of Health. The University of Washington conducted a study of Prazosin in 22 people with Alzheimer’s-related aggressive agitation. The control group was given 6 mg per day of Prazosin over eight weeks. The control group and the placebo group were evaluated on global impression of change and the neuropsychiatric inventory (NPI), and Prazosin outperformed the placebo in the study.
Proper use of Prazosin
Instructions for Taking Prazosin
Any person taking Prazosin should be instructed on the proper use of the medication. The following constitute some recommendations about taking the drug:
- Take the medication at the same time everyday.
- It is recommended that the initial dose of Prazosin be taken at bedtime.
- Take any missed dose as soon as remembered. Never double up on doses.
- Record the patient’s weight twice weekly and note any signs of fluid retention (swelling in the feet, legs, or hands).
- Keep scheduled appointments, and blood pressure should be checked regularly to determine the patient’s response to the medication.
- If the patient is having laboratory tests, inform the personnel because this medication may affect drug-related results.
- The medication may cause dizziness -avoid activities that require alertness (driving, operating heavy machinery, etc.).
- Avoid sudden changes in position, for it may cause dizziness due a drop in blood pressure.
- Avoid hot showers and standing for long periods of time, for this may cause dizziness.
- Avoid exercising in hot weather and avoid central nervous system depressants like alcohol, for these may cause the blood pressure to drop and could lead to dizziness or drowsiness.
- Inform your healthcare provider if you are taking any over the counter or herbal medications, for these may interact with Prazosin (it is a good idea to take the bottles to your appointments).
- Consult with your healthcare provider before taking any over the counter cold or allergy remedies.
- Keep Prazosin in a container that it came in tightly closed, at room temperature, and away from excess moisture and heat.
- Keep this and all medications out of the reach of children.
- Continue taking this medication even if you start feeling better.
- Please comply with any extra interventions suggested by your healthcare provider, such as weight reduction, low-sodium diet, regular exercise, stress management, smoking cessation, etc.
- Inform all of the patient’s physicians of all of the medications that the patient is taking; take all of the patient’s med bottles to the doctors’ appointments so that they know the names and strengths of the patient’s medications, and so that they will also know which pharmacy the patient goes to; this helps to prevent over-medicating and mixing medications that are contraindicated
- Fill all prescriptions at the same pharmacy; this helps with convenience and will also keep the pharmacist aware of any new medications that may interact with current medications
- Do not stop taking Prazosin abruptly, without consulting your healthcare provider. Some conditions could get worse, and the medication may need to be gradually reduced.
Role of norepinephrine
Desired Effect of Prazosin
Prazosin acts by increasing the inner diameter of the arteries and veins, a process that is referred to as dilation. It has a direct effect on the smooth muscles of the vasculature. Prazosin blocks the alpha-adrenergic receptors, a process that leads to a decrease in contractions in the smooth muscles of the prostate, which in turn leads to lowering blood pressure, decreasing the cardiac work load, and decreasing symptoms of enlarged prostates (urinary urgency, urinary hesitancy and nocturia)
Side effects of Prazosin
Adverse Reactions and Side Effects of Prazosin
Adverse reactions and side effects are possible responses to medication outside of the desired effect. Not every person will experience the following reactions; it is important, however, to be aware of what to expect in case reactions occur:
Central Nervous System Reactions
Respiratory System Reactions
- Shortness of breath
- Angioedema (an allergic reaction where the tongue swells)
- Nasal congestion
Cardiovascular System Reactions
- Atrial fibrillation
- Orthostatic Hypotension
- Peripheral edema (swelling in the feet, legs, arms and hands)
- Syncope (fainting)
- Allergic reaction
- Thrombocytopenic purpura (excessive bruising and/or bleeding)
- Alopecia (loss of hair)
Musculoskeletal System Reactions
- Back pain
- Extremity pain
- Non-cardiac chest pain
Gastrointestinal System Reactions
- Priapism (painful erection)
- Urinary frequency
- Leukopenia (increased white blood cell count)
- Hyperlipidemia (high cholesterol
- Blurred vision
- Nose bleeds
- Reddened sclera
Drug Interactions with Prazosin
It is important to inform your healthcare provider of any medications that you are taking. Some medications that can interact with Prazosin include:
- Beta blockers (atenolol, metoprolol, and propranolol)
- Erectile dysfunction medications
- Pulmonary hypertension medications
- Nitrates (nitroglycerine)
- Anti-seizure medications (Tegretol)
- Medications for sleep or anxiety (alprazolam, valium, or ambien)
- Muscle relaxants (cyclobenzaprine)
- Narcotic pain relievers (codeine)
- Psychiatric medications (chlorpromazine, amitriptyline, trazodone)
- Nonsteroidal Anti-inflammatory Drugs (NSAIDs)
Precautions for Prazosin
These medications can have an increased hypotensive effect and cause the person’s blood pressure to drop dangerously low, or they can cause the medication to be ineffective. It is important that the patient’s healthcare provider is aware of all of the meds that are being taken.
The following people should avoid taking Prazosin or take with caution under the care of their physician:
- Patients with kidney disease (May have increased sensitivity to the medication and require a lower dose)
- Women who are pregnant or breastfeeding (Safety has not been established for use)
- Patients with Angina Pectoris
- Patients using diuretics (Decrease dose of prazosin, due to additive effects)
- Patients that are having cataract surgery (Increased risk of intraoperative floppy iris syndrome, which can lead to trauma and tears in the iris)
- Older patients (May cause significant hypotension and or syncope – will require a lower dose if indicated, and can increase the likelihood of a fall).
What to Do in Case of a Prazosin Overdose
If too much Prazosin is taken, seek emergency medical attention right away. Symptoms of overdose include feeling drowsy or faint. If you are unsure, contact Poison Control at 1-800-222-1222. Take the bottle to the hospital so that healthcare personnel will know when the medication was last filled, how many pills are in the bottle and where the medication was filled. This is important information for healthcare personnel when trying to determine if an overdose has occurred accidentally or on purpose.
When to Call the Doctor
With all of the possible side effects of this medication, it is important to know when to call the physician. One of the most common side effects of Prazosin is dizziness. A person taking Prazosin should change positions slowly, as this usually helps to alleviate the symptoms. If this does not work and dizziness is unrelieved or gets worse, the healthcare provider should be notified. Other symptoms include:
- Fast or pounding heartbeat
- Fluttering in your chest
- Trouble breathing
- Swelling in the hands, legs, feet, or ankles
- An erection that is painful or lasts more than four hours (if not treated immediately could lead to permanent tissue damage and loss of potency)
- Angioedema (this is swelling that could involve the lips, eyes, face, tongue or laryngeal mucosa and can be life threatening due to airway blockage; this is a medical emergency)
Prazosin is a medication that has many uses. It was originally used to treat hypertension, but over the years, it was found to be useful in treating several other conditions. Prazosin has improved the lives of people suffering from hypertension, nightmares and daytime mental disturbances that may relate to post-traumatic stress disorder, Raynaud’s phenomenon, and benign prostatic hypertrophy (BPH).
Prazosin has also shown promise in the treatment of aggression and agitation in individuals with Alzheimer’s disease. There are certain people that should avoid using the medication; these include those with kidney disease, the elderly, and people having surgery (particularly eye surgery). It is best to work closely with a healthcare provider to determine if the benefits of using the medication outweigh the costs. Even though not every person experiences side effects, it is best to be familiar with potential side effects and know when to contact your health provider.
This list is not complete. Other drugs may affect prazosin, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2018 Cerner Multum, Inc. Version: 7.01.
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Prazosin doesn’t alleviate distressing dreams in PTSD
(HealthDay)—Prazosin does not alleviate distressing dreams among veterans with chronic posttraumatic stress disorder (PTSD), according to a study published in the Feb. 8 issue of the New England Journal of Medicine.
Murray A. Raskind, M.D., from the University of Washington School of Medicine in Seattle, and colleagues recruited veterans with chronic PTSD who reported frequent nightmares and randomized them to receive prazosin or placebo (152 participants to each) for 26 weeks.
The researchers observed no significant between-group differences at 10 weeks in the mean change from baseline in the Clinician-Administered PTSD Scale item B2 (recurrent distressing dreams) (between-group difference, 0.2), in the mean change in Pittsburgh Sleep Quality Index (between-group difference, 0.1), or in the Clinical Global Impression of Change scores (between-group difference, 0). No significant differences were seen in these measures at 26 weeks or in other secondary outcomes. The mean difference between the prazosin and placebo groups in the change from baseline in supine systolic blood pressure was a 6.7 mm Hg decrease at 10 weeks. The adverse events of new or worsening suicidal ideation occurred in 8 and 15 percent of those assigned to prazosin or placebo.
“In this trial involving military veterans who had chronic PTSD, prazosin did not alleviate distressing dreams or improve sleep quality,” the authors write.
Several authors disclosed financial ties to pharmaceutical companies, including Pfizer, which manufactures prazosin.
Review: Blood pressure drug effective for treating PTSD-related nightmares More information: Abstract/Full Text (subscription or payment may be required)
Editorial (subscription or payment may be required) Journal information: New England Journal of Medicine
Copyright © 2018 HealthDay. All rights reserved.
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