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Benadryl

Generic name: diphenhydramineDYE-fen-HYE-dra-meen ]
Drug classes: Anticholinergic antiemetics, Anticholinergic antiparkinson agents, Antihistamines, Miscellaneous anxiolytics, sedatives and hypnotics

Medically reviewed by Sanjai Sinha, MD. Last updated on Feb 29, 2024.

What is Benadryl?

Benadryl 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.

Benadryl is used to treat sneezing, runny nose, watery eyes, hives, skin rash, itching, and other cold or allergy symptoms.

Benadryl is also used to treat motion sickness, to induce sleep, and to treat certain symptoms of Parkinson's disease.

Warnings

You should not use Benadryl to make a child sleepy.

When taking Benadryl, use caution driving, operating machinery, or performing other hazardous activities. Diphenhydramine may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.

Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while taking Benadryl.

Do not give this medication to a child younger than 2 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.

Before taking this medicine

You should not use Benadryl if you are allergic to diphenhydramine.

Ask a doctor or pharmacist if it is safe for you to take this medicine if you have other medical conditions, especially:

It is not known whether Benadryl will harm an unborn baby. Ask a doctor before using this medicine if you are pregnant.

Diphenhydramine can pass into breast milk and may harm a nursing baby. Antihistamines may also slow breast milk production. Ask a doctor before using this medicine if you are breast-feeding.

Older adults may be more likely to have side effects from this medicine.

How should I take Benadryl?

Use Benadryl exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended. Cold or allergy medicine is usually taken only for a short time until your symptoms clear up.

Do not give this medication to a child younger than 2 years old. Always ask a doctor before giving a cough or cold medicine to a child. Death can occur from the misuse of cough and cold medicines in very young children.

You should not use Benadryl to make a child sleepy.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

For motion sickness, take Benadryl 30 minutes before you will be in a situation that causes you motion sickness (such as a long car ride, airplane or boat travel, amusement park rides, etc). Continue taking Benadryl with meals and at bedtime for the rest of the time you will be in a motion-sickness situation.

As a sleep aid, take Benadryl within 30 minutes before bedtime.

Call your doctor if your symptoms do not improve after 7 days of treatment, or if you have a fever with a headache, cough, or skin rash.

This medication can affect the results of allergy skin tests. Tell any doctor who treats you that you are using Benadryl.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Since Benadryl is used when needed, you may not be on a dosing schedule. If you are on a schedule, use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What to avoid

Benadryl may cause blurred vision and may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.

Drinking alcohol can increase certain side effects of diphenhydramine.

Ask a doctor or pharmacist before using any other cold, cough, allergy, or sleep medicine. Antihistamines are contained in many combination medicines. Taking certain products together can cause you to get too much of this type of medicine. Check the label to see if a medicine contains an antihistamine.

Benadryl side effects

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

Stop using Benadryl and call your doctor at once if you have:

Common Benadryl side effects may include:

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 other drugs will affect Benadryl?

Ask a doctor or pharmacist before using this medicine if you are also using any other drugs, including prescription and over-the-counter medicines, vitamins, and herbal products. Some medicines can cause unwanted or dangerous effects when used together. Not all possible interactions are listed in this medication guide.

Taking this medicine with other drugs that make you sleepy or slow your breathing can worsen these effects. Ask your doctor before taking Benadryl with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

Popular FAQ

Benadryl should not be taken at the same time as cetirizine because it can increase side effects such as dizziness, drowsiness, and difficulty concentrating. Some people, especially the elderly or children, may also find their thinking, judgement, and coordination impaired. You should also not drink alcohol while taking either of these medications because it can make these side effects worse.

The Hat Man is a fictional figure that started appearing on certain internet sites in the early 2000s that has recently been referred to as the “Benadryl Hat Man” after reports of people hallucinating and sighting him after overconsumption or abuse of Benadryl. Most of these reports have appeared on Reddit or the image-based bulletin site 4chan. Continue reading

Benadryl is quickly absorbed after oral administration and it starts to work within 30 minutes with peak effects reached within one to two hours. The effects of Benadryl last from four to six hours. Benadryl in the injectable form has a rapid onset of action. You will know when Benadryl starts to work because your allergy symptoms, such as congestion, runny nose, itchy eyes, or a skin rash, will start to feel better. Continue reading

Benadryl (generic name: diphenhydramine) is an antihistamine that causes sleepiness in most people. Some people use Benadryl to help with sleep or insomnia, but this should only be for short-term use. Do not use Benadryl to make a child sleepy. Contact your doctor if you or your child are having trouble with sleep. Continue reading

One of the most common side effects with Benadryl is drowsiness, but in some people it can have the opposite effect, known as paradoxical excitation. Instead of feeling sleepy,
you may experience excitation, agitation or insomnia (trouble sleeping), which might make your anxiety symptoms feel worse. This may be more common in young children. Continue reading

Some vets might recommend these human over-the-counter (OTC) products, but at specific doses used only in dogs, as recommended by your vet. Do not use these products in dogs with glaucoma, prostate gland enlargement, and certain stomach, thyroid, seizure, or heart disorders.

  • diphenhydramine (Benadryl)
  • meclizine (Bonine)
  • dimenhydrinate (Dramamine)
Continue reading

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Benadryl only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.