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RESPIRATORY SYSTEM › ANTIHISTAMINES FOR SYSTEMIC USE › ANTIHISTAMINES FOR SYSTEMIC USE › Other antihistamines for systemic use
phenindamine
R06AX04
Adult Dosing
- Allergic conditions: 25 mg orally every 4 to 6 hours as needed
- Maximum daily dose: 150 mg
Pediatric Dosing
- Children 6 to 12 years: 12.5 mg orally every 4 to 6 hours as needed, maximum 75 mg daily
- Children under 6 years: Safety and efficacy not established
Indications
- Symptomatic relief of allergic conditions including allergic rhinitis, urticaria, and pruritus
Mechanism of Action
- First-generation histamine H1 receptor antagonist
- Competitively blocks histamine binding to H1 receptors, reducing allergic symptoms
- Exhibits mild anticholinergic and central nervous system depressant properties
Contraindications
- Hypersensitivity to phenindamine or other piperidine-derivative antihistamines
- Use in newborn or premature infants
- Concurrent use with monoamine oxidase inhibitors (MAOIs)
- Narrow-angle glaucoma, symptomatic prostatic hypertrophy, or bladder neck obstruction
Adverse Reactions
- Drowsiness, sedation, dizziness, and fatigue
- Anticholinergic effects: dry mouth, blurred vision, urinary retention, and constipation
- Gastrointestinal disturbances: nausea, vomiting, or epigastric distress
- Paradoxical CNS stimulation in pediatric patients (nervousness, tremor)
Drug Interactions
- Central nervous system depressants (alcohol, barbiturates, opioids, sedatives) enhance sedative effects
- Monoamine oxidase inhibitors (MAOIs) prolong and intensify the anticholinergic effects of antihistamines
- Drugs with significant anticholinergic properties (tricyclic antidepressants, atropine) increase risk of additive adverse effects
Curated Content: Needs Vetting Before Put to Clinical Use