Antibiotics do not affect the drug Depo Provera, according to Family Doctor. The drug, which is an injected contraceptive, is used by women as a method of contraception. It is effective for three months.
It can take about six months for a woman to become fertile again after taking Depo Provera, Family Doctor notes. The drug contains a man-made version of progesterone, a female hormone. It works by stopping the ovaries from releasing eggs. Many women have no periods or light periods while on the drug. It is better at preventing pregnancy than contraceptive pills at almost 100 percent effectiveness. Some women who do not have a period for an extended time may suffer bone loss from taking the drug.