Usual dose and frequency differ from other tetracyclines; exceeding recommended dosage can increase adverse effects. Adults: 200 mg on day 1 (100 mg every 12 hours), then 100 mg/day once daily or 50 mg every 12 hours. More severe infections, particularly chronic urinary tract infections: 100 mg every 12 hours.
Children above 8 years weighing <=100 lb: 2 mg/lb on day 1 in two doses, then 1 mg/lb/day in one or two doses. Severe infection: up to 2 mg/lb/day. Above 100 lb, use adult dose. Antibacterial serum activity usually persists 24 hours at recommended dosage. Treat streptococcal infection for 10 days.
Take capsules/tablets with adequate fluid to reduce esophageal irritation/ulceration. If gastric irritation occurs, give with food or milk; absorption is not markedly affected. Usual doses do not lead to excessive accumulation in renal impairment in the studies described by the source.
Historical indication regimens on this source: uncomplicated gonorrhea except male anorectal infection, 100 mg orally twice daily for 7 days; alternate single-visit regimen, 300 mg then another 300 mg 1 hour later (food/milk/carbonated beverage permitted). Uncomplicated urethral/endocervical/rectal C. trachomatis and nongonococcal urethritis due to C. trachomatis/U. urealyticum: 100 mg twice daily for 7 days.
Penicillin-allergic early syphilis: 100 mg twice daily for 2 weeks; syphilis >1 year: 100 mg twice daily for 4 weeks. Acute epididymo-orchitis due to N. gonorrhoeae or C. trachomatis: 100 mg twice daily for at least 10 days.
Malaria prophylaxis: adults 100 mg daily; children >8 years, 2 mg/kg daily up to adult dose. Start 1 to 2 days before travel, continue during travel and 4 weeks after departure.
Inhalational anthrax post-exposure: adults 100 mg orally twice daily for 60 days; children <100 lb (45 kg), 1 mg/lb (2.2 mg/kg) twice daily for 60 days; >=100 lb use adult dose.