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Acrivastine

Acrivastine

Semprex Benadryl Allergy Relief

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Updated: December 06, 2025

Overview

Acrivastine is a second-generation antihistamine primarily used for the symptomatic relief of allergic conditions. It is structurally related to triprolidine and exhibits potent H1-receptor antagonism with minimal sedative effects due to poor blood-brain barrier penetration. This fast-acting antihistamine is particularly useful for intermittent allergic symptoms, offering relief within 30-60 minutes of administration. Its short duration of action makes it suitable for as-needed use in allergic rhinitis and urticaria, with clinical effects lasting approximately 8-12 hours.

Drug Class

Selective H1-receptor antagonist Second-generation antihistamine

Mechanism of Action

Competitively blocks histamine H1 receptors in peripheral tissues Prevents histamine-mediated allergic responses including vasodilation, increased vascular permeability, and smooth muscle contraction Minimal anticholinergic effects and low CNS penetration due to its zwitterionic structure

Pharmacokinetics

Absorption: Rapidly absorbed from GI tract with 35-45% oral bioavailability Distribution: Limited tissue distribution (Vd ~0.5 L/kg), plasma protein binding ~50% Metabolism: Undergoes minimal hepatic metabolism (~15%) Excretion: Primarily excreted unchanged in urine (~65% within 24 hours) Half-life: 1.5-2 hours in healthy adults

Pharmacodynamics

Onset of action within 30-60 minutes Peak effect at 1.5-2 hours Duration of action 8-12 hours Minimal effect on QT interval Low affinity for muscarinic receptors

Indications

• Symptomatic relief of seasonal allergic rhinitis (hay fever) • Management of chronic idiopathic urticaria • Perennial allergic rhinitis

Contraindications

Absolute: • Hypersensitivity to acrivastine or other alkylamine antihistamines • Severe renal impairment (CrCl <15 mL/min) Relative: • Moderate renal impairment • Pregnancy and breastfeeding • Patients undergoing allergen immunotherapy

Dosage & Administration

Allergic rhinitis/urticaria (adults and children >12 years): 8 mg three times daily Renal impairment: CrCl 30-60 mL/min: 8 mg twice daily CrCl 15-30 mL/min: 8 mg once daily

Special Populations

Pediatric: Not recommended for children <12 years Geriatric: Use with caution due to potential age-related renal impairment Renal impairment: Dose adjustment required (see dosage section) Hepatic impairment: No specific recommendations - use with caution

Adverse Effects

Common (>10%): • Headache (15%) • Somnolence (12%) • Dry mouth (10%) Serious (<1%): • Angioedema • Anaphylaxis • Seizures (rare)

Drug Interactions

• CNS depressants: May potentiate sedative effects • Alcohol: May enhance CNS depression • MAO inhibitors: May potentiate anticholinergic effects • Anticholinergic drugs: Additive anticholinergic effects

Warnings & Precautions

• May impair alertness - caution when driving or operating machinery • Use with caution in patients with urinary retention or glaucoma • Risk of photosensitivity reactions • Not recommended for prolonged continuous use

Pregnancy & Lactation

Pregnancy: Category B - use only if clearly needed Limited human data, animal studies show no teratogenicity Lactation: Excreted in breast milk - not recommended during breastfeeding

Monitoring Parameters

• Symptom relief and allergy control • Renal function in patients with impairment • CNS effects (somnolence, dizziness) • Signs of hypersensitivity reactions

Patient Counseling

• Take as directed, preferably with water • Avoid alcohol and other CNS depressants • May cause drowsiness - use caution when driving • Report any severe side effects immediately • Do not exceed recommended dosage

Storage & Stability

Store at room temperature (15-25°C) Protect from light and moisture Keep in original packaging until use

Clinical Pearls

• Ideal for intermittent allergic symptoms due to rapid onset • Less likely to cause sedation than first-generation antihistamines • Consider dose reduction in elderly patients • Short half-life makes it suitable for patients requiring flexible dosing

References

• British National Formulary (BNF) - Acrivastine monograph • Micromedex DrugDex® Evaluation: Acrivastine • Simons FER, et al. H1-antihistamines: More relevant than ever in allergic rhinitis. J Allergy Clin Immunol Pract. 2013 • Patel P, et al. Acrivastine: A review of its pharmacology and clinical efficacy in allergic disorders. Drugs. 1994