Uses of Allergy Diphenhydramine

Diphenhydramine is an antihistamine commonly used to relieve symptoms of allergies, hay fever, and the common cold. It is also used for other purposes due to its sedative and anticholinergic properties.

Precautions and Warings

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Asthma or breathing problems: Diphenhydramine can cause the secretions produced in the lungs to become thick and difficult to clear out of the lungs. If you have breathing problems such as asthma or chronic obstructive pulmonary disease (COPD), discuss with your doctor discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Drowsiness/reduced alertness: This medication can cause drowsiness. Avoid driving or operating machinery until you have determined that this medication does not affect your ability to perform these tasks safely.

Glaucoma: This medication may cause the symptoms of glaucoma (increased pressure in the eye) to become worse. If you have glaucoma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Report any changes in vision to your doctor as soon as possible while you are taking this medication.

Skin conditions: The topical cream should not be used on chickenpox, measles, or extensive areas of the skin. Avoid applying the cream to raw or open areas of skin. If the condition worsens or lasts for longer than 7 days, contact your doctor. Other medications containing diphenhydramine (e.g., tablets, capsules, liquids) should not be used while using the cream.

Stomach ulcers: This medication may make the symptoms of stomach ulcers worse. If you have stomach problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Urinary tract problems: This medication can make passing urine more difficult, increasing the symptoms of an enlarged prostate gland or other urinary tract problems. If you have prostate problems or difficulty passing urine, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: The safety of using this medication while breast-feeding has not been established. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: Children are at an increased risk of overdose and side effects from this medication. Antihistamines such as diphenhydramine can cause excitation in young children.

Seniors: If you are a senior, this medication may be more likely to cause dizziness, drowsiness, and low blood pressure. Talk to your doctor or pharmacist before taking this medication.

Dosage

Adults and children 12 years of age and older: The usual dose is 25 mg to 50 mg taken by mouth 3 or 4 times a day. No more than 300 mg should be taken in a 24-hour period.

Side Effects

Common Side Effects:

• constipation
• dry mouth
• drowsiness
• dizziness
• excitation (especially in children)
• nausea
• nervousness
• restlessness
• ringing in the ears
• thickening of mucus
• trouble sleeping

Serious Side Effects:

• blurred vision or any change in vision
• confusion
• difficult or painful urination
• rapid or pounding heart beat