Children's Benadryl Allergy Oral Precautions and Side Effects

  • Precautions

    Before taking diphenhydramine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. 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 (e.g., asthma, emphysema)
    • glaucoma
    • heart problems
    • high blood pressure
    • liver disease
    • mental/mood changes
    • seizures
    • stomach problems (e.g., ulcers, obstruction)
    • an overactive thyroid gland
    • difficulty urinating (e.g., due to an enlarged prostate gland)

    This drug may make you dizzy or 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. Limit the use of alcohol and certain other medications that cause drowsiness. (See also Drug Interactions.)

    To minimize dizziness and lightheadedness, get up slowly when rising from a seated or lying position.

    The rapidly-dissolving, liquid, and chewable preparations of this product may contain aspartame. If you have phenylketonuria (PKU) or any other condition that requires you to restrict your intake of aspartame (or phenylalanine), consult your doctor or pharmacist regarding the safe use of this medicine.

    Liquid preparations of this product may contain sugar and/or alcohol. Caution is advised if you have diabetes, alcohol dependence or liver disease. Ask your doctor or pharmacist about the safe use of this product.

    Caution is advised when using this drug in children because they are more sensitive to the effects of antihistamines. This drug can often cause excitement in young children instead of drowsiness.

    Caution is advised when using this drug in the elderly because they may be more sensitive to its effects, especially dizziness, drowsiness and low blood pressure.

    This drug should be used only if clearly needed during pregnancy. Tell your doctor if you are pregnant before using this medication.

    This drug passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

    Side Effects

    Drowsiness, dizziness, headache, constipation, stomach upset, vision changes (e.g., blurred vision), irritability, decreased coordination, or dry mouth/nose/throat may occur. These effects may decrease as your body adjusts to the medication. If any of these effects persist or worsen, inform your doctor.

    To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water or use a saliva substitute. Diphenhydramine can dry up and thicken mucus in your lungs, making it more difficult to breathe and clear your lungs. To help prevent this effect, be sure to drink plenty of fluids unless otherwise directed by your physician.

    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 rare but serious side effects occur:

    • pounding/irregular heartbeat
    • ringing in the ears
    • seizure
    • difficulty urinating

    A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include:

    • 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.