STI

The 2021 CDC STI Treatment Guidelines represent significant updates in antimicrobial selection driven by resistance patterns. Key changes: (1) Gonorrhea: ceftriaxone dose increased from 250 mg to 500 mg IM (1g if ≥150 kg); azithromycin 1g is NO LONGER routinely added as dual therapy (previously 250 mg CTX + 1g azithromycin since 2012). The change reflects increasing gonococcal azithromycin resistance and the recognition that ceftriaxone monotherapy at higher dose is sufficient. Dual therapy with doxycycline is only added when chlamydia co-infection is not excluded. (2) Chlamydia: doxycycline 100 mg BID × 7 days is now PREFERRED over azithromycin 1g single dose. Azithromycin's inferiority for rectal chlamydia (82% vs. 97% cure rate) and concerns about increasing Mycoplasma genitalium azithromycin resistance drove this change. (3) Trichomoniasis in women: metronidazole 500 mg BID × 7 days replaces the single 2g dose (multi-dose has 18% higher cure rate in women; single dose remains acceptable in men). (4) PID: ceftriaxone dose increased to 500 mg IM (from 250 mg) + doxycycline 100 mg BID × 14 days ± metronidazole 500 mg BID × 14 days....