Antibiotics and hormonal birth control effectiveness

(1) Dear Alice, I heard that while it's generally not advised to take antibiotics while on the birth control pill, it's still okay to take tetracycline. Is this true? (2) Dear Alice, I have heard many many times that antibiotics interfere with the effectiveness of oral contraceptives, but what about the depo-provera shot? Is there any research showing decreased effectiveness of Depo-Provera when using anti-biotics? Answer Dear Readers, It's great that you both are being proactive about your physical and reproductive health! To answer both of your questions generally: there?s not sufficient evidence to suggest that the use of broad-spectrum antibiotics (which include tetracycline, Reader #1) decreases the effectiveness of hormonal birth control methods including the combination pill [2], patch [3], ring [4], progestin-only pills [5], implant [6], injection [7] (Depo-Provera), and intrauterine devices [8] (IUDs). However, it has been established that the effectiveness of some hormonal contraceptives (not including Depo-Provera) can be compromised, thus increasing the risk of unintended pregnancy, by two other types of antibiotics: rifampin and rifabutin. And, though there is no conclusive evidence thus far that broad-spectrum antibiotics pose a significant risk to the hormonal contraceptive efficacy, some studies have noted that more research may be needed to further clarify whether there is a link or not.