Therapeutic: allergy, cold, and cough remedies, antihistamines
Relief of symptoms of seasonal allergic rhinitis. Management of chronic idiopathic urticaria.
Antagonizes the effects of histamine at peripheral histamine-1 (H1) receptors, including pruritus and urticaria. Also has a drying effect on the nasal mucosa. Therapeutic Effects: Decreased sneezing, rhinorrhea, itchy eyes, nose, and throat associated with seasonal allergies. Decreased urticaria.
Adverse Reactions/Side Effects
CNS: drowsiness, fatigue. GI: dyspepsia. Endo: dysmenorrhea.
PHYSICAL THERAPY IMPLICATIONS
Examination and Evaluation
Monitor symptoms of seasonal allergies (sneezing, rhinitis, itching eyes, cough) or chronic idiopathic urticaria (rash, hives, itching) to help document benefits of this drug in treating these disorders.
Guard against falls and trauma (hip fractures, head injury, and so forth). Implement fall-prevention strategies, especially in older adults or if balance is impaired (see Appendix E).
Advise patient about the risk of daytime drowsiness and decreased attention and mental focus. Although the risk of drowsiness is lower with this drug compared to traditional antihistamines, patients should use care if driving or in other activities that require quick reactions and strong concentration.
Advise patient to avoid alcohol and other CNS depressants because of the increased risk of sedation and adverse effects.
Instruct patient to report other troublesome side effects, including menstrual irregularities or upset stomach.
Absorption: Rapidly absorbed after oral administration.
Metabolism and Excretion: 80% excreted in urine, 11% excreted in feces.
Half-life: 14.4 hr (increased in renal impairment).
TIME/ACTION PROFILE (antihistaminic effect)
|ROUTE ||ONSET ||PEAK ||DURATION |
|PO ||within 1 hr ||2–3 hr ||12–24 hr |
Contraindicated in: Hypersensitivity.
Use Cautiously in: Impaired renal function (increased dosing interval recommended); OB, Pedi: Pregnancy or lactation (safety not established).
Drug-Drug: Magnesium and aluminum-containing antacids ↓ absorption and may decrease effectiveness.
Drug-Food: Apple, orange, and grapefruit juice ↓ absorption and may decrease effectiveness.
PO (Adults and Children ≥12 yr): 60 mg twice daily; or 180 mg once daily.
PO (Children 2–11 yr): 30 mg twice daily.
PO (Children 6 months–2 yr): 15 mg twice daily.
PO (Adults): 60 mg once daily as a starting dose.