The usual dose of oral doxycycline is 200 mg on the first day of treatment followed by a maintenance dose of 100 mg per day. The maintenance dose may be taken as a single dose or as 50 mg every 12 hours.
Your doctor may prescribe 100 mg every 12 hours for severe infections such as chronic urinary tract infection.
For Uncomplicated Gonorrhea
The usual dose is 100 mg by mouth, twice a day for 7 days. An alternate, single-day treatment is 300 mg, followed in 1 hour by a second 300-mg dose.
For Primary and Secondary Syphilis
The usual dose is 200 mg a day, divided into smaller, equal doses for 14 days.
For Inhalational Anthrax
To prevent or combat infection after exposure, the usual dose is 100 mg taken by mouth twice a day for 60 days. Treatment can be started intravenously, but should be switched to oral doses as soon as possible.
For Prevention of Malaria
The usual dose is 100 mg a day. Treatment should begin 1 to 2 days before travel to the area where malaria is found, then continue daily during travel in the area and 4 weeks after leaving.
For children above 8 years of age, the recommended dosage schedule for those weighing 100 pounds or less is 2 mg per pound of body weight, divided into 2 doses, on the first day of treatment, followed by 1 mg per pound of body weight given as a single daily dose or divided into 2 doses on subsequent days.
For more severe infections, up to 2 mg per pound of body weight may be used.
For inhalational anthrax in children weighing less than 100 pounds, the usual dose is 1 mg per pound of body weight twice daily for 60 days.
For prevention of malaria, the recommended dose is 2 mg per 2.2 pounds of body weight up to 100 mg.
For children over 100 pounds, the usual adult dose should be used.