Which medication is the treatment of choice for Trichomonas vaginitis?

• A. Metronidazole
• B. Valacyclovir
• C. Ceftriaxone
• D. Doxycycline

Answer: (A)

Metronidazole is used because Trichomonas vaginalis is an anaerobic protozoan that responds best to nitroimidazole antibiotics. Metronidazole achieves high cure rates for this infection and is the standard first-line therapy. It can be given as a single 2 g oral dose or as 500 mg twice daily for 7 days, with partner treatment to prevent reinfection. Alcohol should be avoided during treatment and for 24 hours after finishing the course due to a risk of a disulfiram-like reaction. The other drugs listed do not target Trichomonas vaginitis: valacyclovir treats herpes simplex, ceftriaxone targets gonorrhea, and doxycycline treats certain bacteria like Chlamydia but not the protozoan parasite responsible for this infection.