Benadryl (Diphenhydramine Hydrochloride) Patient Information

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Generic Name: Diphenhydramine hydrochloride
Brand Names: Benadryl

Other Brand Names: Aler-Tab, Allergy, Allermax, Altaryl, Children's Allergy, Diphen Cough, Diphenhist, Dytuss, Q-Dryl, Siladryl, Silphen Cough, Simply Sleep, Sleep-ettes, Sominex Maximum Strength Caplet, Theraflu Thin Strips Multi Symptom, Triaminic Thin Strips Cough & Runny Nose, Unisom Sleepgels Maximum Strength, Valu-Dryl.

Benadryl (diphenhydramine hydrochloride) full prescribing information

What is Benadryl?

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Benadryl is an antihistamine. Diphenhydramine blocks the effects of the naturally occurring chemical histamine in the body.

Benadryl is used to treat sneezing; runny nose; itching, watery eyes; hives; rashes; itching; and other symptoms of allergies and the common cold.

Benadryl is also used to suppress coughs, to treat motion sickness, to induce sleep, and to treat mild forms of Parkinson's disease.

Benadryl may also be used for purposes other than those listed in this medication guide.

Important information about Benadryl

Use caution when driving, operating machinery, or performing other hazardous activities. Benadryl 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.

Before taking Benadryl

Benadryl (Diphenhydramine Hydrochloride) Patient InformationDo not take Benadryl if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. A very dangerous drug interaction could occur, leading to serious side effects.

Before taking Benadryl, tell your doctor if you have

  • glaucoma or increased pressure in the eye
  • a stomach ulcer
  • an enlarged prostate, bladder problems or difficulty urinating
  • an overactive thyroid (hyperthyroidism)
  • hypertension or any type of heart problems
  • asthma

You may not be able to take Benadryl, or you may require a lower dose or special monitoring during treatment if you have any of the conditions listed above.

Benadryl is in the FDA pregnancy category B. This means that it is not expected to be harmful to an unborn baby. Do not take Benadryl without first talking to your doctor if you are pregnant. Infants are especially sensitive to the effects of antihistamines, and side effects could occur in a breast-feeding baby. Do not take Benadryl without first talking to your doctor if you are nursing a baby.

If you are over 60 years of age, you may be more likely to experience side effects from Benadryl. You may require a lower dose of Benadryl.

How should I take Benadryl?

Take Benadryl exactly as directed on the package or as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.

Take each dose with a full glass of water.

Benadryl can be taken with or without food.

For motion sickness, a dose is usually taken 30 minutes before motion, then with meals and at bedtime for the duration of exposure.

As a sleep aid, Benadryl should be taken approximately 30 minutes before bedtime.

To ensure that you get a correct dose, measure the liquid forms of Benadryl with a special dose-measuring spoon or cup, not with a regular tablespoon. If you do not have a dose-measuring device, ask your pharmacist where you can get one.

Never take more of Benadryl than is prescribed for you. The maximum amount of diphenhydramine that you should take in any 24-hour period is 300 mg.

Store Benadryl at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and take only the next regularly scheduled dose. Do not take a double dose of Benadryl unless otherwise directed by your doctor.

What happens if I overdose?

Seek emergency medical attention if an overdose is suspected.

Symptoms of a Benadryl overdose include extreme sleepiness, confusion, weakness, ringing in the ears, blurred vision, large pupils, dry mouth, flushing, fever, shaking, insomnia, hallucinations, and possibly seizures.

What should I avoid while taking Benadryl?

Use caution when driving, operating machinery, or performing other hazardous activities. Benadryl 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.

Benadryl side effects

Stop taking Benadryl and seek emergency medical attention if you experience an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives).

Other, less serious side effects may be more likely to occur. Continue to take Benadryl and talk to your doctor if you experience

  • sleepiness, fatigue, or dizziness
  • headache
  • dry mouth
  • difficulty urinating or an enlarged prostate

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?

Do not take Benadryl if you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate) in the last 14 days. A very dangerous drug interaction could occur, leading to serious side effects.

Talk to your pharmacist before taking other over-the-counter cough, cold, allergy, or insomnia medications. These products may contain medicines similar to Benadryl, which could lead to an antihistamine overdose.

Before taking Benadryl, tell your doctor if you are taking any of the following medicines:

  • anxiety or sleep medicines such as alprazolam (Xanax), diazepam (Valium), chlordiazepoxide (Librium), temazepam (Restoril), or triazolam (Halcion)
  • medications for depression such as amitriptyline (Elavil), doxepin (Sinequan), nortriptyline (Pamelor), fluoxetine (Prozac), sertraline (Zoloft), or paroxetine (Paxil)
  • any other medications that make you feel drowsy, sleepy, or relaxed

Drugs other than those listed here may also interact with Benadryl. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines, including vitamins, minerals, and herbal products.

Where can I get more information?

  • Your pharmacist can provide more information about Benadryl.

What does my medication look like?

Diphenhydramine is available with a prescription and over the counter generically and under many brand names as tablets, capsules, an elixir, and a syrup. Other formulations may also be available. Ask your pharmacist any questions you have about Benadryl, especially if it is new to you.

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

Last Updated: 05/2006

Benadryl (diphenhydramine hydrochloride) full prescribing information

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