Benadryl is a brand of various antihistamine medications used to stop allergies, whose content varies in different countries, but which includes some or no combination of diphenhydramine, acrivastine, and cetirizine. It is sold by Johnson & Johnson. In the United States and Canada, the active ingredient is diphenhydramine. In the United Kingdom, the active ingredients of Benadryl are the antihistamines acrivastine or cetirizine. Some forms of this product has been discontinued or withdrawn for safety or efficacy reasons
Benadryl is used to relieve allergy symptoms such as sneezing, itching, runny nose, rash, and hives. Some forms of Benadryl are to be taken orally, while some creams and gels are to be applied to the skin. Benadryl is also sold as a cough medicine in Australia and New Zealand containing diphenhydramine, as well as the antitussive dextromethorphan or the expectorant guaifenesin.
How Benadryl Works
This medication works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. Its drying effects on such symptoms as watery eyes and runny nose are caused by blocking another natural substance made by your body (acetylcholine).
How should this medicine be used?
Diphenhydramine comes as a tablet, a rapidly disintegrating (dissolving) tablet, a capsule, a liquid-filled capsule, a dissolving strip, powder, and a liquid to take by mouth. When diphenhydramine is used for the relief of allergies, cold, and cough symptoms, it is usually taken every 4 to 6 hours. When diphenhydramine is used to treat motion sickness, it is usually taken 30 minutes before departure and, if needed, before meals and at bedtime. When diphenhydramine is used to treat insomnia, it is taken at bedtime (30 minutes before planned sleep). When diphenhydramine is used to treat abnormal movements, it is usually taken three times a day at first and then taken 4 times a day. Follow the directions on the package or on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take diphenhydramine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor or directed on the label.
How Long Does It Take For Benadryl To Work?
Generally, it takes between 20 to 30 minutes for Benadryl to begin to work after oral administration and reaches peak levels in the body in approximately two hours. This is because for most people, Benadryl is absorbed quickly in the body. The medicine should continue to work for about four to six hours.
Medical professionals recommend that you should only take Benadryl for a short amount of time, unless your doctor tells you to take it for longer. If you use Benadryl for two weeks or longer, your body can start to become dependent on it.
What happens if you accidentally take 4 Benadryl?
Taking more than the normal Benadryl dosage can be harmful. Serious diphenhydramine side effects from too much of the drug can include nausea, vomiting, blurred vision, trouble breathing, hallucinations, unconsciousness, and seizures. In case of overdose, call 911 or Poison Control at 1-800-222-1222.
What side effects should I expect when using Benadryl?
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- Drowsiness and sedation may impair judgment and affect a person’s ability to drive or operate machinery. Alcohol should be avoided because it can make this side effect worse.
- Dizziness, low blood pressure, a headache, rapid heartbeat, disturbed coordination, abdominal discomfort and thickening of mucus in the airways may also occur. Elderly people may be more sensitive to effects such as dizziness, sedation, and low blood pressure.
- Benadryl has an atropine-like effect and may cause a dry mouth, which may increase the risk of dental caries and worsen the symptoms of gastroesophageal reflux disease (GERD) if taken regularly.
- Not suitable for use in women who are breastfeeding or young children. Elderly people may be more susceptible to the side effects of sedation, dizziness, and low blood pressure (all of which may increase their risk of falls).
- Overdosage of Benadryl has been associated with hallucinations, convulsions, and death.
- May interact with several other drugs including benzodiazepines, antidepressants, antipsychotics, and alcohol.
- May not be suitable for some people including those with respiratory diseases such as asthma, narrow-angle glaucoma, peptic ulcer disease, intestinal obstruction, high blood pressure or heart disease, high thyroid levels, an enlarged prostate, or a narrowing of the neck of the bladder. Do not use in people who are hypersensitive to Benadryl.