What over-the-counter (OTC) antihistamines are available for relief from allergic symptoms?

Over-the-Counter Oral Antihistamines

The following second-generation oral antihistamines are available over-the-counter (OTC) for allergic symptom relief: cetirizine, loratadine, fexofenadine, and levocetirizine. 1, 2, 3

Second-Generation OTC Antihistamines (Preferred)

These are the preferred first-line agents due to superior safety profiles compared to first-generation antihistamines:

Cetirizine (Zyrtec)

• Dosing: Adults and children ≥6 years: 10 mg once daily 1, 2
• Dosing: Children 2-5 years: 5 mg once daily 1
• Available OTC as tablets and liquid formulations 2
• Most potent antihistamine available but may cause sedation in approximately 10% of patients 4

Loratadine (Claritin)

• Dosing: Adults and children ≥6 years: 10 mg once daily 1
• Dosing: Children 2-5 years: 5 mg once daily 1
• Available OTC 1
• Minimal sedation risk 5

Fexofenadine (Allegra)

• Dosing: Adults and children ≥12 years: 60 mg twice daily or 180 mg once daily 1
• Available OTC 1
• Offers best overall balance of effectiveness and safety with essentially no sedation 4
• May require twice-daily dosing for optimal 24-hour coverage 6

Levocetirizine (Xyzal)

• Dosing: Adults and children ≥12 years: 5 mg once daily 1, 3
• Dosing: Children 6-11 years: 2.5 mg once daily 1
• Available OTC as "original prescription strength" 3
• Highly potent but may cause somnolence in susceptible individuals 6

Important Safety Considerations

First-generation antihistamines (diphenhydramine, chlorpheniramine) should be avoided despite OTC availability due to significant sedation, cognitive impairment, anticholinergic effects, and documented fatalities, particularly in children under 6 years. 1, 7, 8

Key Advantages of Second-Generation Agents

• Minimal to no sedation (except cetirizine in ~10% of patients) 4
• Once or twice-daily dosing improves adherence 5
• No anticholinergic effects 8
• Adverse effects similar to placebo overall 4
• Safe for use while driving and working 6

Clinical Pitfalls to Avoid

• Do not use first-generation OTC antihistamines in children under 6 years due to serious safety concerns including 69 documented fatalities (41 in children under 2 years) between 1969-2006 7
• Antihistamines provide limited relief of nasal congestion compared to other symptoms 5
• Second-generation antihistamines are generally more effective for seasonal allergic rhinitis than perennial allergic rhinitis 5
• OTC antihistamines are less effective than intranasal corticosteroids for comprehensive symptom control 1