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RESPIRATORY SYSTEM › ANTIHISTAMINES FOR SYSTEMIC USE › ANTIHISTAMINES FOR SYSTEMIC USE › Phenothiazine derivatives
methdilazine
R06AD04
Forms & Strengths
- Oral tablet: 3.6 mg
- Oral syrup: 3.6 mg/5 mL
Adult Dosing
- Allergic conditions: 3.6 mg to 7.2 mg orally two to four times daily
- Maximum daily dose typically not exceeding 28.8 mg
Pediatric Dosing
- Children over 3 years: 3.6 mg orally two to four times daily as needed
- Adjust dose based on age and clinical response
Indications
- Symptomatic relief of various allergic conditions including urticaria, rhinitis, and pruritus
Mechanism of Action
- Phenothiazine derivative acting as a histamine H1-receptor antagonist
- Exhibits central nervous system depressant, anticholinergic, and antiemetic properties
Contraindications
- Hypersensitivity to methdilazine or other phenothiazines
- Severe central nervous system depression or comatose states
- Concurrent use with large amounts of central nervous system depressants
Adverse Reactions
- Drowsiness and sedation
- Anticholinergic effects (dry mouth, blurred vision, urinary retention, constipation)
- Dizziness, hypotension, and extrapyramidal symptoms at higher doses
Drug Interactions
- Enhanced CNS depression with alcohol, barbiturates, opioids, and sedatives
- Additive anticholinergic effects when co-administered with other anticholinergic agents
- Potentiation of antihypertensive medications leading to increased hypotension risk
Curated Content: Needs Vetting Before Put to Clinical Use