High-dose Oral Amoxicillin Plus Probenecid Is Highly Effective for Syphilis in Patients With HIV Infection

Clin Infect Dis. 2015 Jul 15;61(2):177-83. doi: 10.1093/cid/civ270. Epub 2015 Mar 31.

Abstract

Background: Intramuscular benzathine penicillin G (BPG) is widely used for the treatment of syphilis. However, BPG is not available in some countries. This study examined the effectiveness and safety of high-dose oral amoxicillin plus probenecid for the treatment of syphilis in patients with human immunodeficiency virus type 1 (HIV-1).

Methods: This retrospective observational study included 286 HIV-infected male patients with syphilis (median age, 36 years; median CD4 count, 389 cells/µL) who were treated with oral amoxicillin 3 g plus probenecid. Syphilis was diagnosed by both serum rapid plasma reagin (RPR) titers ≥8 and positive Treponema pallidum hemagglutination test. Patients with neurosyphilis diagnosed by cerebrospinal fluid examination were excluded. Successful treatment was defined as a at least 4-fold decrement in RPR titer.

Results: The overall treatment efficacy was 95.5% (95% confidence interval [CI], 92.4%-97.7%; 273/286 patients), and efficacy for primary, secondary, early latent, late latent, and unknown duration syphilis was 93.8% (95% CI, 68.1%-99.8%; 15/16), 97.3% (95% CI, 92.9%-99.2%; 142/146), 100% (95% CI, 90.5%-100%; 37/37), 85.7% (95% CI, 58.6%-96.4%; 18/21), and 92.4% (95% CI, 81.9%-97.3%; 61/66), respectively. Treatment duration was mostly 14-16 days (49.7%) or 28-30 days (34.3%), with efficacy of 94.4% (134/142) and 95.9% (94/98), respectively; 96.3% of successfully treated patients achieved a ≥4-fold decrement in RPR titer within 12 months. Adverse events were noted in 28 (9.8%) patients, and 25 of these (89.3%) were successfully treated. Only 6% of patients underwent lumbar puncture.

Conclusions: The combination of oral amoxicillin 3 g plus probenecid was highly effective and tolerable for the treatment of syphilis in patients with HIV-1 infection.

Keywords: HIV; MSM; amoxicillin; syphilis; treatment.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adult
  • Amoxicillin / administration & dosage*
  • Amoxicillin / adverse effects
  • Amoxicillin / therapeutic use
  • Anti-Bacterial Agents / administration & dosage*
  • CD4 Lymphocyte Count
  • Drug Therapy, Combination
  • HIV Infections / complications*
  • Humans
  • Male
  • Probenecid / administration & dosage*
  • Probenecid / adverse effects
  • Probenecid / therapeutic use
  • Retrospective Studies
  • Risk Factors
  • Syphilis / complications*
  • Syphilis / diagnosis
  • Syphilis / drug therapy*
  • Syphilis / immunology
  • Syphilis / prevention & control
  • Syphilis Serodiagnosis
  • Treatment Outcome
  • Young Adult

Substances

  • Anti-Bacterial Agents
  • Amoxicillin
  • Probenecid