Background Our purpose was to assess adverse reactions to doxycline in adolescents under treatment for PID.

Methods At the Harris County (Houston), Texas, USA Juvenile Detention Center from May 2008 through January 2010, we evaluated adolescents in whom we diagnosed PID. We used the diagnostic criteria and outpatient antibiotic regimen for PID recommended by the CDC. We gave 250 mg ceftriaxone intramuscularly once, and, if they were not pregnant, vomiting, or ill enough to also require metronidazole, we prescribed doxycline, 100 mg twice a day for 14 days. The doxycycline was given before, during, or after breakfast, and approximately 2 h after supper. With the medicine, patients were routinely given a packet of two crackers. We re-assessed these patients at 48–72 h and again at least at 7 and 14 days. At each follow-up, we discussed side effects of doxycycline.

Results We evaluated 141 consecutive patients in whom we made the diagnosis of mild to moderate PID: 55% were black, 31% Hispanic, and 15% white. The mean age (SD) was 15.4 (1.2) years. Of the 141 patients, 86 (61%) had no problems when the doxycline was given with two crackers. Forty-five (32%) required more substantial food to avoid nausea and/or vomiting: the medication was given immediately after breakfast or with a sandwich after supper. Those who had side effects in the morning had usually skipped breakfast. Ten (7%) complained of significant gastrointestinal side effects that were not relieved by the simultaneous ingestion of food, and we gave a dose of promethezine 1 h before the doxycycline.

Conclusion 39% of our patients required more than a small amount of food (two crackers) to avoid gastrointestinal side effects from doxycline. Our results suggest that clinicians should advise adolescents to take this antibiotic after eating a greater amount of food if a small snack does not prevent this problem. Because some patients (7%) did not tolerate doxycline even after they ate a meal or a sandwich, we also recommend early contact with patients who have PID to assess the need to change medications or to add an anti-emetic.