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Diphenhydramine (By mouth)

Diphenhydramine (dye-fen-HYE-dra-meen)

Treats symptoms caused by hay fever, allergies, or the common cold. May be used as a nighttime sleep aid. This medicine is an antihistamine.

Brand Name(s):

Aler-Dryl, Aller-G-Time, Allergy Relief, Allergy Relief Medicine, Allermax, Anti-Hist, Banophen, Benadryl Allergy, Children's Allergy, Children's Benadryl Allergy, Children's Triaminic Allergy, Children's Triaminic Cough & Runny Nose, Children's Wal-Dryl Allergy, Complete Allergy, Complete Allergy Medicine

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have ever had an allergic reaction to diphenhydramine. This medicine should not be given to women who are breast feeding. Do not give any over-the-counter (OTC) cough and cold medicine to a baby or child under 4 years old. Using these medicines in very young children might cause serious or possibly life-threatening side effects.

How to Use This Medicine:

Capsule, Thin Sheet, Dissolving Tablet, Tablet, Liquid, Liquid Filled Capsule, Chewable Tablet

  • Take your medicine as directed.
  • Follow the instructions on the medicine label if you are using this medicine without a prescription.
  • Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
  • Swallow the capsule, tablet, and liquid filled capsule whole. Do not crush, break, or chew it.
  • The chewable tablet must be chewed completely before you swallow it.
  • Make sure your hands are dry before you handle the disintegrating tablet. Peel back the foil from the blister pack, then remove the tablet. Do not push the tablet through the foil. Place the tablet in your mouth. After it has melted, swallow or take a drink of water.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Do not freeze the liquid.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are using an MAO inhibitor (MAOI) such as Eldepryl®, Marplan®, Nardil®, or Parnate®.
  • Ask your doctor before you use any other products that have diphenhydramine in it. This includes medicines that you use on your skin.
  • Tell your doctor if you drink alcohol or if you are using any medicine that makes you sleepy, such as allergy medicine or narcotic pain medicine.
  • Do not drink alcohol while you are using this medicine.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have an enlarged prostate, or trouble urinating. Tell your doctor if you have glaucoma, or a breathing problem such as emphysema, bronchitis, or asthma. Make sure your doctor knows if you have any other allergies.
  • This medicine may make you dizzy or drowsy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert.
  • This medicine might contain phenylalanine (aspartame). This is a concern if you have a disorder called phenylketonuria (a problem with amino acids). If you have this condition, talk to your doctor before using this medicine.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Hallucinations (seeing things that are not really there).
  • Lightheadedness or fainting.
  • Pain when urinating, or change in how much or how often you urinate.

If you notice these less serious side effects, talk with your doctor:

  • Clumsiness.
  • Constipation, nausea, or stomach upset.
  • Dry nose, mouth, or throat.
  • Nervousness or excitability, especially in children.
  • Upset stomach.
  • Thick mucus in your nose or throat.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088


Last Updated: 8/4/2014


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