Minor
Doxycycline × Ethinylestradiol
Tetracyclines×Estrogens. Natural and semisynthetic estrogens, plain
Mechanism
Doxycycline does not affect hepatic ethinylestradiol metabolism. The historical theory of reduced COC efficacy via suppression of enterohepatic recirculation is rejected by meta-analyses.
Symptoms
The combination usually causes no specific symptoms. Each drug's individual side effects remain.
Management
Additional contraception during short doxycycline courses is not needed. For long-term therapy (e.g. acne, Lyme disease), no adjustment either.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.