Diphenhydramine Hydrochloride

Diphenhydramine is indicated for the treatment of followings:

• Seasonal, perennial, vasomotor rhinitis
• Urticaria, angioneurotic oedema, anaphylaxis
• Pruiritic conditions
• Premedication for emesis and motion sickness
• Miscellaneous like meniere's disease and parkinsonism

Diphenhydramine is an antihistamine with anticholinergic and sedative effects. It competes with histamine for H1-receptor sites on effector cells in the GI tract, blood vessels and respiratory tract.

Adult-

• Most allergic conditions: 25-50 mg three times a day with a further 50 mg at night.

Children-

• 1 to 5 years of age: 5 mg i.e., 2.5 ml of elixir 4 times a day
• More than 6 years of age: 10 mg i.e. 5 ml of elixir 4 times a day

Diphenhydramine administration significantly reduces the absorption of the antituberculous agent para-aminosalicyclic acid (PAS) from the gastrointestinal tract. CNS depressants may potentiate the sedative action of Diphenhydramine. Anticholinergic drugs may potentiate Diphenhydramine’s anticholinergic side effects.

Known hypersensitivity to Diphenhydramine Hydrochloride, Ammonium chloride is contra-indicated in presence of impaired hepatic or renal function.

Side effect includes sedation, dizziness, tinnitus, fatigue, ataxia, blurred vision, diplopia, euphoria, and epigastric discomfort.

Category B: There are no adequate and well controlled studies in pregnant women using diphenhydramine hydrochloride. Therefore, diphenhydramine hydrochloride should be used in pregnancy only if clearly needed. Diphenhydramine hydrochloride has been reported to be excreted in breast milk and thus, use of diphenhydramine hydrochloride in lactating mother is not recommended.

Caution should be exercised with patients in whom drowsiness is undesirable e.g., drivers, machine operators. Concomitant consumption of alcohol or central nervous system (CNS) depressants will potentiate drowsiness.

Symptoms: Impaired consciousness; psychosis, seizures, antimuscarinic symptoms (e.g. mydriasis, tachycardia, tachyarrhythmias), resp failure, rhabdomyolysis; acute delirium with visual and auditory hallucination (topical).

Management: Supportive and symptomatic treatment. Convulsions and marked CNS stimulation may be treated with IV diazepam.

Sedating Anti-histamine

Store between 15-30° C. Protect from moisture.