What is a recommended antihistamine/decongestant combination for postnasal drainage?

Recommended Antihistamine/Decongestant Combination for Postnasal Drainage

For postnasal drainage, use a first-generation antihistamine (dexbrompheniramine 6 mg or azatadine 1 mg) combined with sustained-release pseudoephedrine 120 mg, both given twice daily. 1

Why First-Generation Antihistamines Are Superior

The anticholinergic properties of first-generation antihistamines are essential for treating postnasal drainage, which is typically non-histamine-mediated. 1 This is a critical distinction:

• Second-generation antihistamines (loratadine, terfenadine, fexofenadine) are ineffective for postnasal drainage and acute cough associated with nonallergic rhinitis. 1
• First-generation antihistamine/decongestant combinations have been proven effective in randomized, double-blind, placebo-controlled studies specifically for this condition. 1
• The combination provides more effective relief of nasal congestion than antihistamines alone (OR of treatment failure 0.31,95% CI 0.20 to 0.48; NNTB 3.9). 1, 2

Specific Dosing Regimens

Proven effective combinations:

• Dexbrompheniramine maleate 6 mg + pseudoephedrine sulfate 120 mg (sustained-release), twice daily 1
• Azatadine maleate 1 mg + pseudoephedrine sulfate 120 mg (sustained-release), twice daily 1

Expected Timeline and Response

• Improvement typically occurs within days to 2 weeks of initiating therapy. 1
• On final evaluation (3-10 days), 70% of patients on active treatment show favorable response versus 55% on placebo. 2

Managing Side Effects

To minimize sedation (the primary concern with first-generation antihistamines):

• Start with once-daily dosing at bedtime for several days, then advance to twice-daily dosing. 1
• This strategy can obviate sedation problems in many patients. 1

Other potential side effects from the decongestant component:

• Insomnia, urinary difficulty (especially older men), jitteriness, tachycardia, worsening hypertension, increased intraocular pressure in glaucoma patients. 1
• Adverse effects occur in approximately 31% of patients on antihistamine-decongestant combinations versus 13% on placebo. 2

When First-Generation Combinations Are Contraindicated

If the patient cannot tolerate first-generation antihistamine/decongestant combinations, consider:

• Ipratropium bromide nasal spray as an alternative, particularly effective for rhinorrhea. 1, 3
• This is especially appropriate for patients with glaucoma or symptomatic benign prostatic hypertrophy where anticholinergic effects are problematic. 1

Special Populations

For patients with hypertension:

• Oral decongestants can elevate blood pressure through alpha-adrenergic receptor stimulation. 4
• Use only in patients with controlled hypertension and monitor blood pressure closely. 4
• Consider intranasal corticosteroids as first-line alternative therapy instead. 4, 5

For pediatric patients (ages 5-12):

• The combination of pseudoephedrine with chlorpheniramine has demonstrated safety when used concomitantly with ipratropium bromide nasal spray. 3
• Safety and effectiveness in children under 5 years have not been established. 3

Critical Pitfall to Avoid

Do not use second-generation antihistamines (loratadine, fexofenadine, cetirizine) for postnasal drainage. While these agents are effective for allergic rhinitis, they lack the anticholinergic properties necessary to address non-histamine-mediated postnasal drainage. 1 Multiple studies have demonstrated their ineffectiveness for this specific indication. 1