Allergy (Diphenhydramine HCl) is an antihistamine that is used to treat sneezing, runny nose, watery eyes, hives, skin rash, itching, and other cold or allergy symptoms.

Allergy (Diphenhydramine HCl) is also used to treat motion sickness, to induce sleep, and to treat certain symptoms of Parkinson's disease. Allergy (Diphenhydramine HCl) sleep aid medicine is not for use in children younger than 12 years old.

There are many brands and forms of Allergy (Diphenhydramine HCl) available. Not all brands are listed on this leaflet.

Allergy (Diphenhydramine HCl) may also be used for purposes not listed in this medication guide.

Use Allergy (Allergy (Diphenhydramine HCl) HCl) exactly as directed. Taking too much Allergy (Diphenhydramine HCl) can lead to serious heart problems, seizures, coma, or death.

Do not use this medicine to make a child sleepy. Allergy (Diphenhydramine HCl) sleep aid medicine is not for use in children younger than 12 years old.

Use exactly as directed on the label, or as prescribed by your doctor. Allergy (Diphenhydramine HCl) is only for short-term use until your symptoms clear up.

Taking too much Allergy (Diphenhydramine HCl) can lead to serious heart problems, seizures, coma, or death.

Always follow directions on the medicine label about giving Allergy (Diphenhydramine HCl) to a child. Do not use the medicine only to make a child sleepy. Death can occur from the misuse of antihistamines in very young children.

For motion sickness, take Allergy (Diphenhydramine HCl) 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 Allergy (Diphenhydramine HCl) with meals and at bedtime for the rest of the time you will be in a motion-sickness situation.

As a sleep aid, take Allergy (Diphenhydramine HCl) within 30 minutes before bedtime.

You must chew the chewable tablet before you swallow it.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Remove an orally disintegrating tablet from the package only when you are ready to take the medicine. Place the tablet in your mouth and allow it to dissolve, without chewing. Swallow several times as the tablet dissolves.

Call your doctor if the condition you are treating with Allergy (Diphenhydramine HCl) does not improve, or if you have a fever with a headache, cough, or skin rash.

Do not use Allergy (Diphenhydramine HCl) for longer than 2 weeks to treat sleep problems, or longer than 7 days to treat cold or allergy symptoms.

Allergy (Allergy (Diphenhydramine HCl) HCl) can affect the results of allergy skin tests. Tell any doctor who treats you that you are using Allergy (Diphenhydramine HCl).

Store at room temperature away from moisture and heat.

You should not use Allergy (Diphenhydramine HCl) if you are allergic to it.

Ask a doctor or pharmacist if this medicine is safe to use if you have ever had:

• an enlarged prostate or urination problems;

• asthma, chronic obstructive pulmonary disease (COPD), or other breathing disorder;

• glaucoma; or

• a thyroid disorder.

Ask a doctor before using this medicine if you are pregnant or breastfeeding. Allergy (Diphenhydramine HCl) may slow breast milk production.

Since Allergy (Allergy (Diphenhydramine HCl) HCl) is used when needed, you may not be on a dosing schedule. Skip any missed dose if it's almost time for your next dose. Do not use two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of Allergy (Diphenhydramine HCl) can be fatal.

Overdose symptoms may include vomiting, confusion, severe drowsiness, ringing in your ears, no urination, very dry eyes and mouth, dilated pupils, fast heartbeats, tremor, agitation, hallucinations, or seizure.

Avoid driving or hazardous activity until you know how Allergy (Allergy (Diphenhydramine HCl) HCl) will affect you. Your reactions could be impaired.

Drinking alcohol can increase certain side effects of Allergy (Diphenhydramine HCl).

Ask a doctor or pharmacist before using any other medicine that may contain Allergy (Diphenhydramine HCl). This includes medicines for sleep, cold/allergy symptoms, or anti-itch medicine used on the skin. Using too much Allergy (Diphenhydramine HCl) may lead to a fatal overdose.

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

Stop using Allergy (Diphenhydramine HCl) and call your doctor at once if you have:

• severe drowsiness; or

• painful or difficult urination.

Side effects such as dry mouth, constipation, and confusion may be more likely in older adults.

Common side effects of Allergy (Diphenhydramine HCl) may include:

• drowsiness;

• dry eyes, blurred vision;

• dry mouth, nose, or throat;

• decreased urination;

• constipation;

• feeling restless or excited (especially in children); or

• day-time drowsiness or "hangover" feeling after night-time use.

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.

Ask a doctor or pharmacist before using Allergy (Diphenhydramine HCl) with any other medicines, especially drugs that can cause drowsiness (such as opioid medication, sleep medicine, a muscle relaxer, or medicine for anxiety or seizures). Tell your doctor about all your current medicines and any medicine you start or stop using. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.