Which of the following regimens is acceptable for prostatitis in a mature male with prostatic secretions showing inflammation?

• A. Ciprofloxacin 750 mg PO bid for 10 days
• B. Ampicillin 1 g IV q12H and Gentamicin 1 mg/kg IV q18H for 10 days
• C. Trimethoprim-sulfamethoxazole 160/800 mg PO bid for 21 days
• D. Metronidazole 250 mg PO t.i.d for 7 days

Answer: (C)

Antibiotics for prostatitis must reach the prostate in effective concentrations and cover the usual pathogens, mainly Enterobacteriaceae such as E. coli. Trimethoprim-sulfamethoxazole given twice daily penetrates prostatic tissue well and is active against these organisms, making a three-week course a reasonable option for prostatitis treatment in many cases.

The other regimens are less suitable for this condition. A fluoroquinolone for only ten days doesn’t provide an adequate duration for prostatitis, where several weeks are typically needed. A combination of ampicillin and gentamicin is less ideal because aminoglycosides have poor penetration into prostatic tissue, reducing effectiveness against prostatitis pathogens. Metronidazole targets anaerobes and has limited activity against the common Gram-negative prostatitis agents, so it wouldn’t be an appropriate first-line choice.