Chapter 31: Sexually Transmitted Infections – Drug Treatments

The comprehensive Chapter 31 provides an expert overview of the clinical recognition, diagnostic procedures, and pharmacological management for prevalent sexually transmitted infections (STIs), highlighting their extensive public health impact and economic costs worldwide. Focusing on best practices defined by current guidelines, the therapeutic objective for all STIs is the swift eradication of the pathogen and the prevention of resulting complications, such as infertility or maternal-fetal transmission. The discussion begins with Chlamydial infection, caused by Chlamydia trachomatis, emphasizing its frequent asymptomatic presentation and the utilization of the Nucleic Acid Amplification Test (NAAT) as the diagnostic benchmark. Preferred pharmacotherapy involves single-dose Azithromycin or a short course of Doxycycline, with special attention given to alternative regimens for pregnant individuals where drugs like Doxycycline are contraindicated. Next, Gonorrhea, caused by Neisseria gonorrhoeae, is covered; because coinfection with chlamydia is common and antibiotic resistance is a growing concern, dual therapy is mandated, typically consisting of intramuscular Ceftriaxone paired with oral Azithromycin. Management of syphilis, caused by the spirochete Treponema pallidum, is centered entirely on parenteral penicillin G for all stages—primary, secondary, and latent—with alternatives reserved for nonpregnant, penicillin-allergic patients and mandatory desensitization required for pregnant women. For viral infections, Genital Herpes Simplex Virus (HSV) cannot be cured, but symptoms are controlled through systemic antiviral agents like Acyclovir, Valacyclovir, or Famciclovir, administered for initial outbreaks, episodic recurrences, or daily suppression in frequent cases. The chapter also details Pelvic Inflammatory Disease (PID), an ascending infection typically caused by N. gonorrhoeae and C. trachomatis, which requires prompt, broad-spectrum antibiotic coverage to safeguard reproductive health. Finally, Human Papillomavirus (HPV) infection and associated genital warts are discussed; while treatments such as Podofilox or Trichloroacetic Acid (TCA) can remove visible lesions, they do not eliminate the persistent virus, underscoring the critical role of the HPV vaccination in prevention against high-risk types.