Metronidazole Dosing for Trichomoniasis Single-Dose Treatment
You need four 500mg tablets of metronidazole to achieve the 2g single dose for trichomoniasis treatment. 1, 2, 3
Simple Math
- Target dose: 2 grams (2000mg)
- Tablet strength: 500mg each
- Number needed: 2000mg ÷ 500mg = 4 tablets 3
Clinical Context
The 2g single dose is a well-established treatment regimen for trichomoniasis:
The CDC recommends metronidazole 2g orally as a single dose as one of the primary treatment options, with cure rates of approximately 90-95%. 1
The alternative regimen is metronidazole 500mg twice daily for 7 days, which is now considered the preferred regimen by more recent guidelines. 2, 4
When to Use Single-Dose vs. Multi-Day Regimen
The 7-day regimen (500mg twice daily) is preferred because it achieves sustained therapeutic levels in the urethra and perivaginal glands where Trichomonas can persist. 2, 4
The single 2g dose is appropriate when:
- Medication adherence is a major concern 4
- You need to ensure compliance by directly observed therapy 1
- The patient cannot be relied upon to complete a 7-day course 1
Critical Administration Details
- All four 500mg tablets can be given at once to achieve the 2g dose. 3
- Sex partners must be treated simultaneously to prevent reinfection. 1, 2, 4
- Patients must avoid alcohol during treatment and for at least 24 hours after due to disulfiram-like reaction. 4
- Avoid sexual intercourse until both partners complete treatment and are asymptomatic. 1, 2
Common Pitfall
Never use topical metronidazole gel for trichomoniasis—efficacy is less than 50% because it cannot achieve therapeutic drug levels in the urethra or perivaginal glands where the organism resides. 1, 4