Quick Answer
Single-dose cures exist for trichomoniasis (metronidazole 2g once), bacterial vaginosis (sometimes), and gonorrhea (single ceftriaxone injection). Chlamydia moved AWAY from single-dose azithromycin toward 7-day doxycycline based on superior efficacy data — convenience lost to cure-rate mathematics.
- Trichomoniasis: the cleanest one-dose cure in sexual health — four 500mg tablets, once.
- Gonorrhea: one IM injection, though post-treatment retesting at 1–2 weeks monitors resistance.
- Chlamydia's retreat from single-dose: azithromycin 1g underperformed doxycycline in head-to-head trials (97% vs ~74% in rectal infections).
- Everything else requires multi-day or multi-visit commitments.
The Landscape
Single-dose appeal drives adherence perfection — nobody forgets dose one of one. But efficacy data overrides convenience where discrepancies emerge, hence chlamydia's protocol shift despite patient preference for pills-once.
Maximizing single-dose success
Take metronidazole with food avoiding alcohol 24-48 hours (disulfiram reactions are miserable); receive ceftriaxone injections properly intramuscularly; pair either with partner treatment simultaneously.
Why protocols change
Guideline committees weigh emerging trial data annually; yesterday's standard becomes today's suboptimal care. Current CDC STI Treatment Guidelines (updated regularly) supersede older advice including recent-diagnosis instructions from years past.
Treatment Windows by Infection
Bacterial infections clear with antibiotics measured in days: single-dose azithromycin or a ceftriaxone shot for gonorrhea, seven days of doxycycline for chlamydia, penicillin injections for syphilis staged by duration. Viral infections play a longer game — suppressive antivirals for herpes, daily ART driving HIV to undetectable, and 8–12-week antiviral courses curing over 95% of hepatitis C cases.
Sources & Further Reading
- CDC — Sexually Transmitted Infections
- CDC STI Treatment Guidelines
- WHO — Sexually transmitted infections fact sheet
- MedlinePlus — Sexually Transmitted Diseases
Figures reflect CDC surveillance and WHO estimates; they are population statistics, not personal risk predictions.