| Generic Name | Chlorpheniramine Maleate |
|---|---|
| Drug Class | First-Generation H₁ Antihistamine (Alkylamine) |
| Indications |
|
| Mechanism of Action | Competitive H₁ receptor antagonist → inhibits histamine-mediated vasodilation, capillary permeability, and itching; crosses BBB causing mild to moderate sedation. |
| Available Forms & Strengths | • Tablet: 4 mg • Syrup: 2 mg/5 mL • Injection: 10 mg/mL |
| Dosage | Adults: 4 mg every 4–6 hours (max 24 mg/day) Children 6–12 years: 2 mg every 4–6 hours (max 12 mg/day) Children 2–5 years: 1 mg every 4–6 hours (max 6 mg/day) |
| Route | Oral, IM, IV |
| Common Side Effects |
|
| Serious Adverse Effects | Confusion, hypotension, paradoxical excitation (children), respiratory depression (rare) |
| Contraindications | • Hypersensitivity to chlorpheniramine • Newborns or premature infants (parenteral use) |
| Precautions | • Elderly patients (sedation, falls) • Glaucoma, prostatic hypertrophy • Hepatic or renal impairment |
| Drug Interactions | • Alcohol and CNS depressants (↑ sedation) • MAO inhibitors (↑ anticholinergic effects) |
| Pregnancy & Lactation | Pregnancy: Use if benefit outweighs risk Lactation: May cause infant sedation; use with caution |
| Storage | Store below 30°C, protect from light and moisture |
| References | BNF | BNF for Children | Goodman & Gilman |