Promethazine HCl

Antihistamine, Systemic · H1 receptor antagonist

Indications

Allergic conditions.

Dosage

ORAL: Adults: 10-20 mg two or three times daily. Children: Symptomatic relief of allergy such as hay fever, insomnia associated with urticaria and pruritus: 2-5 yr, 5 mg twice daily or 5-15 mg at night; 5-10 yr, 5-10 mg twice daily or 10-25 mg at night; 10-18 yr, 10-20 mg 2-3 times daily or 25 mg at night increased to 25 mg twice daily if necessary. Sedation (short-term use): 2-5 yr, 15-20 mg; 5-10 yr, 20-25 mg; 10-18 yr, 25-50 mg. Sedation in intensive care: 1 mth-12 yr, 0.5-1 mg/kg, max 25 mg, 4 times daily, adjusted according to response; 12-18 yr, 25-50 mg 4 times daily, adjusted according to response. Nausea and vomiting: The following dose at bedtime on night before travel, repeat following morning if necessary: 2-5 yr, 5 mg; 5-10 yr, 10 mg; 10-18 yr, 20-25 mg. INJECTION: Adults: IM/IV: Allergic conditions: 25 mg, may be repeated in 2 hr. Anti-emetic: 12.5-25 mg every 4-6 hr as…

Administration

Administer IM into deep muscle mass. IV administration is not preferred route. Solution for injection may be diluted in 25-100 mL NS or D5W (max conc. of 25 mg/mL) and infuse over 15-30 min at a rate of 25 mg/min. Compatibility: Stable in NS, D5W, D10W, D5NS, LR, 1/2NS, NS. Stability: Store at controlled room temperature 20°C-25°C (68°F-77°F). Protect from light. Keep covered in carton until time of use. Do not use if solution has developed colour or contains a precipitate.

Adverse Effects

Drowsiness, impaired reactions. Dizziness, disorientation, restlessness, headache, fatigue, anticholinergic effects, photosensitivity. Extra-pyramidal reactions, convulsions (high doses). Hyperexcitability in children.

Risk Factor (Pregnancy/Lactation)

Pregnancy: Risk cannot be ruled out. Lactation: Contraindicated or not recommended. Contraindications: Coma, CNS depression. Precautions: Asthma, severe coronary artery disease, bronchitis, bronchiectasis, narrow angle glaucoma, epilepsy, renal or hepatic impairment, GI or urinary obstruction. Avoid if signs or symptoms of Reye's syndrome.

Interactions

Alcohol, CNS depressants, MAOIs, anticholinergics.

Advice to Patient

Contact prescriber if there is unrelieved nausea or diarrhoea, unusual weight gain, increased sleepiness or stimulation, chest pain or palpitations, sore throat or difficulty in breathing, involuntary movements, restlessness. Avoid alcohol during therapy. Avoid prolonged exposure to sunlight, use sunscreen to prevent photosensitivity.

Pharmacokinetics

Onset of action: Oral, IM: Approx. 20 minutes; IV: Approx. 5 minutes. Duration: Usually 4 to 6 hours (upto 12 hours). Absorption: Oral: Rapid and complete; large first pass effect limits systemic bioavailability. Metabolism: Hepatic. Bioavailability: Oral: Approx. 25%; Rectal: 21.7% to 23.4%. Half-life elimination: : IM: Approx. 10 hours; IV: 9 to 16 hours; Suppositories, syrup: 16 to 19 hour% (range: 4 to 34 hours). Time to maximum serum concentration: Oral (syrup): 2.8 ± 1.4 hours; Rectal: 8.2 ± 3.4 hours. Excretion: Urine, feces as inactive metabolites.

Brands with this active ingredient

Compiled by Healify Pharmacy from published drug references. How we compile it →

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