What are the recommended antibiotics for acute Sexually Transmitted Infections (STIs)?

Recommended Antibiotics for Acute Sexually Transmitted Infections

For gonococcal infections, use ceftriaxone 250 mg IM plus azithromycin 1 g PO as a single dose; for non-gonococcal urethritis/chlamydial infections, use either azithromycin 1 g PO single dose or doxycycline 100 mg PO twice daily for 7 days. 1, 2

Gonococcal Infections (Urethritis, Cervicitis, Rectal)

Dual therapy is mandatory to address chlamydial co-infection and combat antimicrobial resistance: 1, 2

• Ceftriaxone 125-250 mg IM single dose PLUS azithromycin 1 g PO single dose 3, 1, 2
• This combination achieves a 98.9% cure rate for gonococcal cervicitis 2

Critical caveat: Avoid quinolones (ciprofloxacin, levofloxacin) due to widespread resistance exceeding 20% in many populations, particularly in men who have sex with men 3, 1, 2

Disseminated Gonococcal Infection

• Ceftriaxone 1 g IM/IV daily for ≥1 week 3
• Alternative: Cefotaxime 1 g IV every 8 hours for ≥1 week 3

Gonococcal Meningitis/Endocarditis

• Ceftriaxone 1-2 g IV every 12 hours for 10-14 days (meningitis) or ≥4 weeks (endocarditis) 3

Non-Gonococcal Urethritis (Chlamydia trachomatis)

First-line options: 3, 1

• Azithromycin 1 g PO single dose (preferred for compliance) 3, 1
• Doxycycline 100 mg PO twice daily for 7 days (equally effective) 3, 1, 4
• Alternative: Levofloxacin 500 mg PO daily for 7 days 3
• Alternative: Erythromycin base 500 mg PO four times daily for 3 weeks 3

The single-dose azithromycin regimen ensures virtually 100% compliance, addressing the major problem of treatment failure from poor adherence with multi-dose regimens. 5

Recurrent/Persistent Urethritis

• Metronidazole 2 g PO single dose PLUS azithromycin 1 g PO single dose 3

Bacterial Vaginosis

Oral options: 3

• Metronidazole 500 mg PO twice daily for 7 days 3
• Clindamycin 300 mg PO twice daily for 7 days 3

Topical options: 3

• Metronidazole gel 0.75%, one full applicator (5 g) intravaginally daily for 5 days 3
• Clindamycin cream 2%, one full applicator (5 g) intravaginally at bedtime for 7 days 3

Trichomoniasis

• Metronidazole 2 g PO single dose (preferred) 3
• Alternative: Metronidazole 500 mg PO twice daily for 7 days 3
• Alternative: Tinidazole 2 g PO single dose 3

Note: Single-dose metronidazole may cause higher gastrointestinal adverse effects compared to multi-dose regimens, but compliance benefits typically outweigh this concern. 5

Special Population Considerations

Pregnant Women

• Avoid quinolones and tetracyclines entirely 1
• For chlamydia: Use azithromycin 1 g PO single dose 1
• For gonorrhea: Use ceftriaxone 250 mg IM plus azithromycin 1 g PO 1, 2
• For penicillin allergy in syphilis: Desensitization is required, not alternative antibiotics 3

Children

• Tetracyclines (doxycycline, minocycline) are contraindicated in children <8 years of age 3, 6
• Adjust dosing based on weight for other antibiotics 3

HIV-Infected Persons

• Use doxycycline, minocycline, ceftriaxone, and azithromycin with caution as these have not been well-studied in this population 3

Critical Management Principles

Partner notification and treatment is mandatory: All sexual contacts within 60 days must receive empirical treatment for gonorrhea and chlamydia regardless of symptoms. 2

Abstinence requirement: Patients must abstain from sexual activity until both patient and all partners complete therapy and symptoms resolve. 2

Test-of-cure is not routinely needed if symptoms resolve with recommended regimens, but follow-up cultures should be obtained if symptoms persist. 2

Culture before treatment when possible: Obtain cultures from purulent drainage before initiating antibiotics to confirm diagnosis and guide therapy, particularly important given rising resistance patterns. 6