Family Nurse Practitioner Exam

Which of the following drugs does NOT interfere with the metabolism of oral contraceptives?

1. Tetracycline

2. Rifampin

3. Phenytoin (Dilantin)

4. Ciprofloxacin (Cipro)

The correct answer is: Ciprofloxacin (Cipro)

Ciprofloxacin, a fluoroquinolone antibiotic, is the drug that does not interfere with the metabolism of oral contraceptives. This is significant for patients who rely on hormonal contraceptives for pregnancy prevention, as they need to ensure that their chosen medication does not compromise their contraceptive efficacy. Many antibiotics, including tetracycline and rifampin, can impact the metabolic pathways that process oral contraceptives, potentially leading to decreased effectiveness of the contraceptive method. Rifampin, in particular, is known for inducing hepatic enzymes that metabolize estrogen and progestin, which are the active components of most oral contraceptives. Tetracycline has historically been thought to interact with oral contraceptives, although more current research suggests that its impact is minimal yet still warrants caution. Phenytoin, an anticonvulsant, also affects the metabolism of oral contraceptives through enzyme induction, increasing the metabolism rate of hormonal contraceptives and potentially diminishing their effectiveness. Ciprofloxacin, however, does not have the same enzyme-inducing effects, making it a safer choice for those on oral contraceptives. This understanding is crucial for preventing unintended pregnancies in patients using hormonal birth control while being treated with antibiotics.