Minor
Ethinylestradiol × Norfloxacin
Estrogens. Natural and semisynthetic estrogens, plain×Second-generation fluoroquinolone
Mechanism
Norfloxacin does not induce CYP3A4 and does not affect ethinylestradiol metabolism. The historical theory of reduced COC efficacy 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 norfloxacin courses (3–7 days) is not needed.