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RESPIRATORY SYSTEM › ANTIHISTAMINES FOR SYSTEMIC USE › ANTIHISTAMINES FOR SYSTEMIC USE › Other antihistamines for systemic use
thenalidine
R06AX03
Adult Dosing
- Allergic conditions: 20 mg orally 2 to 3 times daily
- Maximum daily dose: 60 mg
Pediatric Dosing
- Safety and efficacy in pediatric patients not well established; use generally avoided or restricted based on age and weight under specialist supervision
Indications
- Symptomatic treatment of allergic disorders including urticaria, rhinitis, and pruritus
Mechanism of Action
- First-generation antihistamine acting as an antagonist at histamine H1 receptors
- Exhibits central nervous system depressant and anticholinergic properties
Contraindications
- Hypersensitivity to thenalidine or other phenothiazine derivatives
- Concurrent use with monoamine oxidase inhibitors (MAOIs)
- Narrow-angle glaucoma
- Symptomatic prostate enlargement or urinary retention
Adverse Reactions
- Drowsiness and sedation
- Dry mouth, blurred vision, and urinary retention
- Dizziness and hypotension
- Gastrointestinal upset
- Rarely: agranulocytosis and leukopenia associated with phenothiazine class
Drug Interactions
- Potentiation of central nervous system depression when combined with alcohol, opioids, barbiturates, or sedatives
- Enhanced anticholinergic side effects when co-administered with other anticholinergic drugs (e.g., tricyclic antidepressants)
- Prolongation of adverse effects when used with MAOIs
Curated Content: Needs Vetting Before Put to Clinical Use