A randomized, double-blind, parallel-group, multicenter, placebo-controlled study of the safety and efficacy of extended-release guaifenesin/pseudoephedrine hydrochloride for symptom relief as an adjunctive therapy to antibiotic treatment of acute respiratory infections.

PURPOSE: This study assessed the efficacy and safety of guaifenesin 600 mg and pseudoephedrine hydrochloride 60 mg extended-release bilayer tablets in providing relief of acute respiratory symptoms when used as an adjunct to antibiotics in patients with an acute respiratory infection (ARI).

METHODS

Adult patients experiencing symptoms of ARI and meeting the physician's usual diagnostic criteria for oral antibiotic treatment were prescribed an antibiotic and randomized to adjunctive guaifenesin/pseudoephedrine hydrochloride or matching placebo twice daily for 7 days. Patients completed symptom diaries and treatment assessments twice daily and attended office visits on Days 4 and 8.

RESULTS

The safety/intent-to-treat (ITT) population analysis included 601 patients (guaifenesin/pseudoephedrine, n = 303; placebo, n = 298). Mean symptom scores were lower with guaifenesin/pseudoephedrine from Day 3 for every symptom assessed, with statistically significant improvements in total symptom score from Day 3 (P = 0.026). The greatest effects of treatment with guaifenesin/pseudoephedrine were observed for nasal congestion and sinus headache. Time to overall relief was shorter with guaifenesin/pseudoephedrine (P = 0.038). Significantly more patients reported "the medication was helping during the day" on Day 2 with guaifenesin/pseudoephedrine (P = 0.002). Patient assessments of symptom relief showed a significant preference for guaifenesin/pseudoephedrine versus placebo (P = 0.021). Treatment with guaifenesin/pseudoephedrine was well tolerated. Insomnia (2.6%), nausea (2.3%), and headache (1.3%) were the most common treatment-related adverse effects.

CONCLUSIONS

As adjunctive therapy for symptom relief for patients taking antibiotics for ARIs, guaifenesin/pseudoephedrine shortened time to relief and improved bothersome respiratory symptoms better than placebo, with greatest effects seen for nasal congestion and sinus headache.