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RESPIRATORY SYSTEM › ANTIHISTAMINES FOR SYSTEMIC USE › ANTIHISTAMINES FOR SYSTEMIC USE › Aminoalkyl ethers
clemastine, combinations
R06AA54
Forms & Strengths
- Oral tablet 1 mg clemastine fumarate + 30 mg pseudoephedrine hydrochloride
- Oral syrup 0.5 mg clemastine + 15 mg pseudoephedrine per 5 mL
Adult Dosing
- Clemastine 1 mg PO once daily (alone)
- Clemastine 1 mg + pseudoephedrine 30 mg PO once daily for allergic rhinitis with congestion
Pediatric Dosing
- Age ≥6 yr: clemastine 0.5 mg + pseudoephedrine 15 mg PO once daily
- Age <6 yr: not recommended
Indications
- Seasonal/perennial allergic rhinitis
- Urticaria and other pruritic skin conditions
- Allergic conjunctivitis
- Common cold with nasal congestion (clemastine‑pseudoephedrine)
Mechanism of Action
- Selective inverse agonist at peripheral H1 histamine receptors → reduces capillary permeability and itching
- Pseudoephedrine is an indirect α‑adrenergic agonist → vasoconstriction of nasal mucosa, decreasing edema
Contraindications
- Known hypersensitivity to clemastine, pseudoephedrine or excipients
- Narrow‑angle glaucoma
- Severe urinary retention or prostatic hypertrophy
- Severe uncontrolled hypertension
- MAO‑inhibitor therapy
- Infants and premature neonates
Adverse Reactions
- Sedation, somnolence
- Dry mouth, thirst
- Dizziness, headache
- Gastro‑intestinal discomfort (nausea, dyspepsia)
- Tachycardia, palpitations (pseudoephedrine)
- Insomnia, nervousness
Drug Interactions
- Additive CNS depression with alcohol, opioids, benzodiazepines
- Increased sympathomimetic effects with other decongestants or stimulants
- Pseudoephedrine effect amplified by MAO‑inhibitors or tricyclic antidepressants
- Potential increased clemastine levels with CYP2D6 inhibitors (e.g., fluoxetine)
- Pseudoephedrine may reduce efficacy of antihypertensive agents
- Concurrent QT‑prolonging drugs may increase risk of arrhythmia
Curated Content: Needs Vetting Before Put to Clinical Use