Table 3 Pharmacology studies
From: Role of guaifenesin in the management of chronic bronchitis and upper respiratory tract infections
| First Author (Year) | Objectives of study | Intervention | Results |
|---|---|---|---|
| Chodosh (1973) | To evaluate sputum changes associated with guaifenesin in chronic bronchial conditions |
Double-blind crossover study: 1 week known placebo +800 mg/day or 2400 mg/day for 4 weeks +1 week unknown placebo +1000 mL extra oral water intake | Significantly uniform and beneficial changes, such as sputum adhesiveness and dry weight, occurred with 2400 mg/day guaifenesin |
| Thomson (1973) | To assess the effect of guaifenesin on mucociliary clearance (MCC) in the human lung from the rate of removal of inhaled radioactive tracer particles |
Double-blind crossover study: 600 mg guaifenesin vs placebo | Significant improvement in mucociliary clearance with guaifenesin in patients with chronic bronchitis but not in healthy subjects |
| Sisson (1995) |
To examine: (i) The effect of guaifenesin on nasal MCC in vivo (assessed by saccharin transit time [STT]) and nasal ciliary beat frequency (CBF; assessed by nasal brushing and ex vivo microscopy), and (ii) whether a relationship exists between nasal CBF and nasal STT |
Double-blind crossover study: 400 mg guaifenesin vs placebo 5× daily from days 1 to 7, or days 14 to 21 |
No significant differences between guaifenesin- or placebo-treated groups in change from baseline values of STT or CBF No relationship observed between STT and CBF from regression analysis |
| Dicpinigaitis (2003) | To evaluate the effect of guaifenesin on cough reflex sensitivity to inhaled capsaicin in healthy subjects and subjects with acute URTIs |
Randomized double-blind study: Single dose of 400 mg guaifenesin vs placebo | Cough reflex sensitivity was statistically significantly decreased with guaifenesin in patients with URTIs but not in healthy subjects |
| Dicpinigaitis (2009) | To evaluate the antitussive effect of the combination of benzonatate and guaifenesin in subjects with acute URTI |
Randomized double-blind crossover study (n = 23): Each subject received 3 of 4 possible study drug/combinations: 600 mg guaifenesin (G), 200 mg benzonatate (B), their combination (B + G), and placebo (P) |
• Guaifenesin (p = 0.01) significantly inhibited cough reflex sensitivity relative to placebo • B + G combination suppressed capsaicin-induced cough significantly more than B (p < 0.001) or G (p = 0.008) alone |
| Bennett (2010) | To determine whether guaifenesin improves MCC in the healthy lung by assessing the rate of removal of inhaled radioactive tracer particles |
Open-label randomized crossover study (n = 8): Single dose of 1200 mg guaifenesin vs placebo over 3 weeks; minimum 7-day washout period | Strong trend toward statistical significance (p = 0.07) for enhanced small airway clearance with guaifenesin vs placebo |
| Bennett (2015) | To determine the effect of guaifenesin on MCC and cough clearance in non-smoking adults with acute URTI by assessing the rate of removal of inhaled radioactive tracer particles |
Randomized double-blind crossover study: Single dose of 1200 mg guaifenesin vs placebo | No significant effect of single dose guaifenesin on mucociliary and cough clearance compared to placebo |