Clindamycin versus trimethoprim-sulfamethoxazole for uncomplicated skin infections.
P : outpatients with uncomplicated skin infections who had cellulitis, abscesses larger than 5 cm in diameter (smaller for younger children), or both
E : Clindamycin for 10 days. n=264
Clindamycin was given as two 150-mg tablets three times daily.
C : Trimethoprim-sulfamethoxazole for 10 days. n=260
TMP-SMX was given at doses of 160 mg of trimethoprim and 800 mg of sulfamethoxazole administered as two single-strength tablets twice daily.
O : The proportion of patients cured was similar in the two treatment groups in the intention-to-treat population (80.3% in the clindamycin group and 77.7% in the TMP-SMX group; difference, -2.6 percentage points; 95% confidence interval [CI], -10.2 to 4.9; P=0.52) and in the populations of patients who could be evaluated (466 patients; 89.5% in the clindamycin group and 88.2% in the TMP-SMX group; difference, -1.2 percentage points; 95% CI, -7.6 to 5.1; P=0.77).
Adverse Events : Overall rates of adverse events were similar in the clindamycin and TMP-SMX groups (18.9% and 18.6%, respectively). The most common adverse events in the clindamycin and TMP-SMX groups were diarrhea (9.7% and 10.1%), nausea (2.3% and 2.7%), vomiting (2.3% and 1.6%), pruritus (1.5% and 1.2%), and rash (1.2% and 0.8%) .There were no cases of Clostridium difficile–associated diarrhea. Most adverse events were mild or moderate and resolved without sequelae.
T : double-blind, RCT
First, we excluded patients with serious coexisting conditions, and the outcomes of skin infections treated with clindamycin and TMP-SMX in populations with such conditions may differ. However, our investigation involved outpatients, the population in which approximately 95% of skin infections are treated, and thus is generalizable to a large population.
Second, we examined only two antibiotics, and the comparative efficacy and side-effect profile of other oral medications are unclear. However, the two antibiotics we studied are those typically recommended by experts in areas of MRSA endemicity.
Third, patients were followed for 1 month after therapy was completed, which is a strength in comparison with studies lacking a documented follow-up visit but is also a limitation. S. aureus infections are often recurrent, and 1 month of follow-up may be inadequate for assessing the efficacy of a drug in preventing recurrent disease.
Fourth, the dosages of clindamycin and TMP-SMX for skin infections are not well defined. Some have suggested using twice the dose we used (see, e.g., ClinicalTrials.gov number NCT00729937), whereas others have recommended the same dose. Our data show that the efficacy of TMP-SMX doses of 160 mg and 800 mg does not differ significantly from that of a commonly recommended dose of clindamycin — specifically, 300 mg three times daily. Finally, the proportions of patients who had an S. aureus isolate that was resistant to clindamycin or TMP-SMX (5.2% and 0.2%, respectively) were relatively low. Given the low prevalence of resistance, its contribution to treatment failure is unclear, although there was a trend toward a lower clindamycin cure rate for infections caused by clindamycin-resistant S. aureus versus clindamycin-susceptible isolates (73.3% vs. 91.7%, P=0.06), which also raises important questions about the spontaneous response rate. The number of patients with inducible clindamycin-resistant isolates was even smaller (three patients in the population that could be evaluated), which precluded making conclusions about its role in treatment failure.