Obenix is one of the leading brands of Phentermine 37.5. It is used together with dieting and regular exercising, to counter obesity in people with risk factors such as high blood pressure, high cholesterol, and diabetes. The drug is only a small part of the weight control program. Hence, one should follow a strict diet, take proper medication, and stick to exercise routines for the drug to have the desired effects. Taking Obenix with any other medication such as fenfluramine or dexfenfluramine can cause a rare fatal lung disorder called pulmonary hypertension. Obenix may be addictive and thus should be used only by person it was prescribed for. Never share phentermine with another person, and especially anyone with history of drug abuse or addiction. As a precaution, do not stop using the drug suddenly, for this could lead to unpleasant withdrawal symptoms. Always ask your doctor how to avoid withdrawal symptoms when you need to stop using Obenix.