Do antibiotics make birth control pills less effective? i just got a prescription for an antibiotic and my pharmacist told me i should use backup birth control for the rest of the month. my doctor never said anything. should i use condoms just to be safe

It : It is very important to use an alternative form of birth control (like condoms) when taking antibiotics, and to be safe, for the rest of the month after you are finished with your regimen. This is because some antibiotics can decrease the effectiveness of the birth control hormones. Yes, you should use a back up form of birth control, like condoms, to avoid getting pregnant.

Most antibiotics OK : Some antibiotics, like rifampin, definitely interact with birth control.Others may in some individuals and with some pills .It probably depends on how your body metabolizes the drugs, and it may also depend on the dose of hormones in the pills.Most small studies don't show differences in the level of hormones in the blood, but to be on the absolutely safe side, use condoms during antibiotic use.