Doxycycline is a tetracycline-class antibiotic sometimes used to treat bacterial prostatitis, especially when caused by atypical or intracellular organisms such as Chlamydia trachomatis or Ureaplasma urealyticum. It works by inhibiting bacterial protein synthesis through binding to the 30S ribosomal subunit. Doxycycline achieves moderate penetration into prostate tissue and is often chosen for sexually transmitted or chronic, low-grade infections. Typical treatment duration ranges from 2–4 weeks for acute infections and up to 6 weeks for chronic or persistent cases. Common side effects include gastrointestinal upset, photosensitivity, and esophageal irritation, so it should be taken with water and not immediately before lying down.