Other Brands/Names

Adidryl, Allerin Expectorant, Andonex, Benacol, Bidryl, Benadyl DMP, Fortusin, Ikadryl, Koffex, Lapisiv, Licodril, Mercydryl, Corsadryl, Dantusil, Prodryl, Deximix, Recodryl. 

How It Works

Diphenhydramine works by blocking the action of histamine, a chemical in the body responsible for causing allergy symptoms such as sneezing, itchy skin rashes, and watery, itchy eyes. This medication helps relieve these common allergy symptoms. In addition, diphenhydramine has an antiemetic effect, which means it can help relieve nausea and vomiting.

Indications

Diphenhydramine is commonly used to treat the following medical conditions, such as insomnia (sleep issues), itchy skin, vertigo (dizziness), or motion sickness.

Contraindications

There are certain conditions that prevent the use of diphenhydramine, including:

• Newborns or premature babies

• Breastfeeding mothers

• Lower respiratory tract diseases, such as asthma

Side Effects

Some of the side effects that can arise include sleepiness, dizziness, dry throat, diarrhea, constipation, loss of appetite, palpitations, tinnitus, and blurred visions.

Types

• 25 mg Tablets

• 12.5 mg/5 mL Syrup

• 1 mL (50 mg/5 mL) and 10 mL (50 mg/5 mL) injectable ampules (prescription required)

• 1% and 2% cream or gel

Dosage

Purpose: To treat allergies and motion sickness (can be taken with or before meals).

Adult dosages:

• 25 – 50 mg, 3 – 4 times daily (maximum daily dose: 300 mg)

Children dosages:

• Ages 2 – 6 years: 6.25 mg every 4 – 6 hours

• Ages 6 – 12 years: 12.5 – 25 mg every 4 – 6 hours

• Ages >12 years: Same as adult dosage

Purpose: To treat itchy skin conditions.

Adult and children’s dosage: Apply 2% cream to the affected area once or twice daily for 3 days.

Safety

Pregnancy:

Diphenhydramine is classified as FDA Category B (animal studies have shown no harm to the fetus, but there are no adequate studies in pregnant women). It is considered likely safe during pregnancy, but its use should still be discussed with a doctor.

Drug Interactions

Anticonvulsants (e.g., diazepam): Concurrent use with anticonvulsants can increase the risk of drowsiness.

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