Did metronidazole cause early period? finished cycle two weeks ago, but started bleeding on and off again, is it the medicine? pap clear, not on bc.

Early period: Menstrual irregularity is generally not a listed side-effect of metronidazole. An occasional irregularity in periods not uncommon among young girls especially if it not related to an early undiagnosed pregnancy. Since you are not on BC, take a pregnancy test if you think it could be a possibility. Otherwise monitor your next cycle and discuss with your doctor if you have concerns.