Primary FDA-Approved Indications
Primary use centers on refractory allergic symptoms; off-label use includes appetite stimulation and migraine prophylaxis when supervised by specialists.
Perennial or seasonal allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis
FDA ApprovedConsider when second-generation antihistamines are ineffective and sedation can be managed; monitor anticholinergic effects.
Treatment Duration
Standard: Short-term courses during symptom flares
Evidence Sources
Chronic urticaria, dermatographism, adjunct after controlled anaphylaxis
FDA ApprovedEmploy as adjunctive therapy when other antihistamines inadequate; ensure epinephrine used for acute anaphylaxis.
Treatment Duration
Standard: Use the shortest effective course