Is dextromethorphan an antihistamine?

SIDE EFFECTS: Drowsiness, dizziness, dry mouth, blurred vision, nausea, trouble sleeping, headache, or constipation may occur. Many of these effects will decrease as your body adjusts to the medication. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.If your doctor has directed you to use this medication, remember that he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor immediately if any of these unlikely but serious side effects occur: mental/mood disorders (such as nervousness, excitement, irritability), fast/pounding/irregular heartbeat, shaking (tremors), difficult/painful urination.Seek immediate medical attention if any of these rare but serious side effects occur: fainting, severe mental/mood changes (such as confusion, hallucinations), seizures.A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking this combination medication, tell your doctor or pharmacist if you are allergic to any of the ingredients; or if you have any other allergies. Also tell your doctor if you have had a bad reaction to decongestants (such as ephedrine, phenylephrine, pseudoephedrine). This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (such as emphysema, chronic bronchitis, asthma, smoker’s cough), cough with blood or large amounts of mucus, high blood pressure, heart disease (such as chest pain, heart failure, heart attack), fast/slow/irregular heartbeat, diabetes, a certain eye problem (glaucoma), seizures, difficulty urinating (such as due to enlarged prostate), overactive thyroid (hyperthyroidism).This drug may make you dizzy/drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Avoid alcoholic beverages.Liquid products may contain sugar, alcohol, and/or aspartame. Caution is advised if you have diabetes, liver disease, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Caution is advised when using this drug in the elderly because they may be more sensitive to its side effects, especially dizziness, drowsiness, and urination problems.Caution is advised when using this drug in children because they may be more sensitive to unusual side effects of the drug, especially excitation, nervousness, or increased blood pressure.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.Some ingredients is this product may pass into breast milk. Discuss the risks and benefits with your doctor before breast-feeding.


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Dextromethorphan is a cough suppressant. It affects the signals in the brain that trigger cough reflex.

Diphenhydramine is an antihistamine that reduces the effects of natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.

Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

Dextromethorphan, diphenhydramine, and phenylephrine is a combination medicine used to treat cough, runny or stuffy nose, sneezing, itching, and watery eyes caused by allergies, the common cold, or the flu.

This medicine will not treat a cough that is caused by smoking, asthma, or bysema.

Dextromethorphan, diphenhydramine, and phenylephrine may also be used for purposes not listed in this medication guide.

Do not use this medicine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

You should not use this medicine if you are allergic to dextromethorphan, phenylephrine, or diphenhydramine.

Do not use dextromethorphan, diphenhydramine, and phenylephrine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

To make sure this medicine is safe for you, tell your doctor if you have:

  • asthma or COPD, cough with mucus, or cough caused by smoking, emphysema, or chronic bronchitis;
  • a blockage in your digestive tract (stomach or intestines);
  • high blood pressure, heart disease;
  • liver or kidney disease;
  • glaucoma;
  • cough with mucus, or cough caused by emphysema or chronic bronchitis;
  • enlarged prostate or urination problems;
  • pheochromocytoma (an adrenal gland tumor);
  • overactive thyroid; or
  • if you take potassium (Cytra, Epiklor, K-Lyte, K-Phos, Kaon, Klor-Con, Polycitra, Urocit-K).

FDA pregnancy category C. It is not known whether dextromethorphan, diphenhydramine, and phenylephrine will harm an unborn baby. Do not use this medicine without a doctor’s advice if you are pregnant.

This medicine can pass into breast milk and may harm a nursing baby. Antihistamines and decongestants may also slow breast milk production. Do not use this medicine without a doctor’s advice if you are breast-feeding a baby.

Antihistamine/Antitussive/Decongestant Combos

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April 17, 2012— — A Colorado girl is dead after taking a lethal combination of two common cold and allergy medicines, and Colorado authorities are investigating her grandmother, who was looking after the tiny 5-year-old.

Kimber Michelle Brown was spending the night with her 59-year-old grandmother, Linda Sheets, at the time of her death on Feb. 12. Sheets was reportedly treating the girl for flu-like symptoms.

The coroner’s report, which came out this week, ruled the overdose was accidental, caused by dextromethorphan, an ingredient commonly used in cough syrup. Kimber’s blood levels were two and a half times higher than the recommended dosage.

She also had higher than therapeutic levels of cetirizine, which is the main ingredient in the allergy medicine Zyrtec.

Kimber’s parents, Raelyn Anderson-Brown and Mike Brown, live in Durango, Colo., which is about nine miles from Hermosa, where she died.

Investigators say Sheets, who is Anderson-Brown’s mother, may not have measured the medicine properly, or the child may have also taken some herself.

Now, the Sixth Judicial District Attorney’s Office is investigating whether criminal charges will be filed, according to the Durango Herald, although police have said so far there is no evidence of wrongdoing.

“I consider it a certified combination of drugs, with the dextromethorphan being the highest level,” La Plata County Coroner Dr. Carol Huser told

Combining the two depressants produced a greater toxicity than each drug would have caused alone, she said.

Blood levels were taken several hours after the child’s death. Those were the only drugs in the girl’s system, except for some that the medic administered “to try to save her,” said Huser.

The toxicology report showed that the little girl, who weighed only 46 pounds, had 96 nanograms per millilitre of dextromethorphan in her blood. The upper limit for this drug in adults is 40 ng/ml.

Kimber also had 490 ng/ml of cetirizine in her system. A normal dosage would be between 271 and 352 ng/ml.

Huser said he had never seen a death from these medications before, but warned about the dangers of over-the-counter medicines.

“As a society in general, we are way too dependent on drugs — we take them as knee-jerk reaction and it’s not wise,” she said.

As for the criminal charges against the family, Huser said, “I can’t speak for the state attorney general, but it’s highly unlikely.”

“I have no reason to suspect any ill intent,” Huser wrote in the toxicology report. “The degree of negligence in either measuring an inappropriate dose or leaving medications within reach of a child does not, in my view, rise to the level I require for a certification of homicide.”

Death from Cough Medicine is Rare

Dr. Douglas Carlson, an emergency room pediatrician at St. Louis Children’s Hospital and Washington University School of Medicine, said the coroner’s report makes sense.

“While death is an unusual side effect of dextromethorphan, it is known to occur,” said Carlson, who did not treat Kimber. “The efficacy of over-the-counter cough medications is minimal in children, so we recommend not using them in less than 2 years and be careful with those under age 6.”

According to the coroner’s report, Kimber complained of leg pain, cramps and muscle spasms hours before her death. Huser said that was consistent with drug toxicity as her body began to shut down.

Carlson said those symptoms were inconsistent with dextromethorphan, which causes “drowsiness and fatigue.”

An overdose of dextromethorphan usually triggers changes in the child’s mental status leading to “irritability and confusion,” according to Carlson. “That’s why teens use it to get high — for the sensory perceptions.”

The drug in higher doses can cause cardiac abnormalities and arrhythmias that can cause the heart to stop functioning, he said.

“Dextromethorphan is the most common ingredient in the country,” said Carlson. “When you use it with small children, make sure to follow the label directions and measuring device with the bottle.”

“I am not aware of fatal reactions when used alone,” he said.

As cetirizine, found in the allergy medicine Zyrtec, Carlson said the package warns that when used with dextromethorphan, the combination can depress the central nervous system or lead to psychomotor impairment.

That drug could have explained the cramping and twitching, according to Dr. John Spangler, an associate professor of family and community medicine at Wake Forest University School of Medicine.

“Instead of sedation, which can occur with antihistamines, some children have a paradoxical reaction,” he said.

But, warned Dr. Donna Seger, medical director of the Middle Tennessee Poison Center, there could have been other issues at play, such as a viral or other infection.

“Had she seen a physician?” she asked.

“We shouldn’t cause a scare about these drugs unless we have evidence that they caused a problem,” said Seger. “A lot of children take these drugs.”

ABC’s Dr. Christopher A. Tokin contributed to this story.

Can you drink alcohol while taking antihistamines?

1. Drowsiness

Share on PinterestBenadryl is a brand of antihistamines commonly used for allergies.

Benadryl can cause side effects, including sedation and drowsiness, which impair coordination and reaction speed.

Mixing Benadryl with alcohol can intensify these side effects and will impair a person’s daily functioning.

This can be life-threatening if it involves certain activities, such as driving or operating heavy machinery.

2. Loss of consciousness

Some people are more prone than others to losing consciousness when sedated. In these people, combining Benadryl and alcohol is more likely to cause a loss of consciousness. This can be harmful due to the likelihood of falls and other accidents.

3. Dehydration

Benadryl and alcohol are both known to dehydrate the body. Mixing them can increase the risk of dehydration. This can cause discomfort at the time and may worsen a hangover.

4. Complications in older adults

Aging slows the body’s ability to break down alcohol so that it may stay in the system of an older adult for longer than someone younger. This slowdown increases the time a person will be at risk of a harmful interaction between Benadryl and alcohol.

5. Learning and memory impairment

Benadryl blocks the action of a neurotransmitter called acetylcholine. Acetylcholine is necessary for learning and memory, so blocking its action may temporarily impair these processes.

Alcohol is also known to inhibit learning and memory temporarily. So, combining alcohol and Benadryl may again have a more noticeable effect on learning and memory.

6. Interactions with other types of medication

Share on PinterestBenadryl may interact with cough and cold medication.

Benadryl may interact with other types of medication, which can heighten the side effects.

Taking these other types of medications with alcohol could also increase the risk of side effects.

Examples of medications that may interact with Benadryl include:

  • antidepressants
  • stomach ulcer medicine
  • cough and cold medicine
  • other antihistamines
  • diazepam (Valium)
  • sedatives

7. Other sources of alcohol

Some types of medication, including cough syrup and laxatives, also contain alcohol. They can include up to 10 percent alcohol, which may interact with Benadryl.

As a consequence, taking Benadryl with these medications when consuming very small amounts of alcohol may still increase the risk of adverse side effects.

8. Sex

In general, females are more susceptible to alcohol-related harm. This is because their bodies typically contain less water for alcohol to mix with, meaning that the same amount of alcohol would be more concentrated in a female than in a male.

Mixing Benadryl with alcohol may be particularly hazardous for females, as consuming smaller amounts of alcohol could trigger adverse interaction effects.

9. Misuse

As Benadryl and alcohol both cause drowsiness and sedation, it may seem tempting to exploit this combination as a sleeping aid. However, this can also heighten other adverse side effects that will interfere with sleep, such as nausea and dizziness.

10. Dementia

Share on PinterestMore studies are required to determine if mixing Benadryl and alcohol causes dementia.

One study found that people who take one anticholinergic drug per day for at least 3 years have a raised risk of dementia. It should be noted that this study included all anticholinergic drugs, not just Benadryl.

Another study in 2018 found excessive alcohol consumption to be associated with a higher risk of dementia. It is possible that consuming large amounts of Benadryl and alcohol over long periods of time could be linked to an increased risk of dementia.

However, longitudinal research would be required in people who consume high levels of Benadryl and alcohol to know whether this has any effect on the risk of dementia.

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