What is the recommended antibiotic regimen for treating epididymo-orchitis in sexually active men under 35 years of age?

For sexually active men under 35 years of age with epididymo-orchitis, the recommended antibiotic regimen is to treat empirically for sexually transmitted infections (STIs). This involves a single dose of ceftriaxone 1 g intramuscularly (IM), plus oral doxycycline 100 mg twice daily for 10–14 days. If cephalosporins and/or tetracyclines are contraindicated, oral ofloxacin 200 mg twice daily for 14 days is an alternative. If the infection is most likely due to chlamydia or other non-gonococcal organisms without risk factors for gonorrhoea, oral doxycycline 100 mg twice daily for 10–14 days or oral ofloxacin 200 mg twice daily for 14 days can be used. If quinolones are contraindicated, oral co-amoxiclav 500/125 mg three times daily for 10 days is recommended. Additionally, if there is a risk of infection with enteric organisms (e.g., men who have insertive anal sex), consider ceftriaxone 1 g IM plus oral ofloxacin 200 mg twice daily for 14 days, or co-amoxiclav if quinolones are contraindicated. Patients should be advised to abstain from sexual contact until treatment completion and follow-up, and urgent referral to a sexual health clinic is recommended if possible.