Sure, you did. But you must have also taken another medication, which interacted with the pill to make it ineffective. This is a typical case of drug interaction - a definite risk when you take more than one medication.

Drug interaction is the action of one drug upon the effectiveness or toxicity of another. Most cases of drug misuse arise when patients change doctors for their problems and receive multiple medications without a primary care physician overseeing the health care of the patient. This can be life threatening at times.

Prevention ::
Avoid self medication. If you have diabetes, asthma, heart ailments, high blood pressure, or if you are on oral contraceptives, inform your doctor. Be aware of what you are consuming- its correct dosage, side effects- ask questions. If you consume alcohol or OTC products be sure to understand how it might react with your medications. Always read the fine print on any prescription label. Watch out for prescription labels that say "Take as directed."