Clindamycin Phosphate/Tretinoin

In drug treatment for acne, topical products alone or in combination with systemic products are commonly prescribed. It was recently pointed out by Chiou that oral tetracyclines, the most commonly prescribed systemic drugs, may not be as effective as commonly assumed because the effect of placebo can approach drug effects during the 4 - 12 weeks of daily administration. The present work evaluated the percent contribution of vehicle (placebo) toward the reported efficacy of reduction in total (inflammatory and non-inflammatory) lesion counts of 8 commonly prescribed topical preparations at the end of 10 - 12 weeks of daily administration. These preparations included 0.1% tretinoin, 0.1% adapalene, 5% dapsone, 1% clindamycin, a combination of benzoyl peroxide with adapalene or clindamycin, and a clindamycin-tretinoin combination. The mean reduction from drugs and vehicles were 42 ± 7.1%, and 23 ± 5.0%, respectively; the mean contribution of vehicle toward drug effect was 55 ± 15% (range 35 - 82%). For 5 benzoyl peroxide preparations evaluated (2 for 2.5%, and 3 for 5.0%), their respective means were 40 ± 9%, and 25 ± 15%, and vehicle-toward-drug contribution was 58 ± 31% (range 9 - 89%). The present work shows the great importance of vehicle effects in topical therapy; in some cases this effect approached 90%. The potential significance of the above findings in the development of more effective topical anti-acne drugs was discussed.

Topical combination therapy containing a retinoid and an antimicrobial is an effective treatment for acne vulgaris.

To evaluate the efficacy and safety of a new topical formulation containing clindamycin phosphate 1.2% and tretinoin 0.025% solubilized in an aqueous-based gel (CT gel).

1,649 participants were randomized 2:2:2:1 to 12 weeks of double-blind treatment with CT gel, clindamycin, tretinoin, or vehicle gel administered once daily.

Significantly more participants achieved 2-grade or greater improvement on the Investigator's Static Global Assessment score with CT gel versus clindamycin, tretinoin, or vehicle gel. CT gel produced a significantly greater reduction in absolute number of total lesions versus all other treatment groups, in total and noninflammatory lesions versus clindamycin, and in total and inflammatory lesions versus tretinoin. Local tolerability was similar to that of tretinoin alone; signs and symptoms of irritation were most notable at week 2. There were no more adverse events with CT gel than with tretinoin gel.

CT gel is more effective than clindamycin or tretinoin monotherapy, with a safety and tolerability profile similar to that of tretinoin.