Which type of medication can decrease the effectiveness of combined oral contraceptives?

Which type of medication can decrease the effectiveness of combined oral contraceptives?

• A. Medications that induce hepatic enzymes
• B. Drugs that slow gastric emptying
• C. Vitamins
• D. Antacids

Answer: (A)

Medications that induce hepatic enzymes decrease the effectiveness of combined oral contraceptives by increasing the metabolism of the hormones in the liver. When liver enzymes are boosted, ethinyl estradiol and progestin are cleared faster, lowering their circulating levels and reducing the contraceptive protection. This is why enzyme-inducing drugs can lead to breakthrough ovulation and unintended pregnancy. Examples include certain anticonvulsants (like phenytoin and carbamazepine), rifampin, and St. John’s wort. Because of this interaction, use backup contraception during the inducer therapy and for a period after stopping, until enzyme activity and hormone levels return to baseline. Other types of drugs, such as those that slow gastric emptying, vitamins, or antacids, do not have the same reliable impact on the pill’s effectiveness.

Medications that induce hepatic enzymes decrease the effectiveness of combined oral contraceptives by increasing the metabolism of the hormones in the liver. When liver enzymes are boosted, ethinyl estradiol and progestin are cleared faster, lowering their circulating levels and reducing the contraceptive protection. This is why enzyme-inducing drugs can lead to breakthrough ovulation and unintended pregnancy. Examples include certain anticonvulsants (like phenytoin and carbamazepine), rifampin, and St. John’s wort. Because of this interaction, use backup contraception during the inducer therapy and for a period after stopping, until enzyme activity and hormone levels return to baseline. Other types of drugs, such as those that slow gastric emptying, vitamins, or antacids, do not have the same reliable impact on the pill’s effectiveness.