Phentermine is a potent stimulant used to suppress appetite in patients that did not respond to other methods. Do not combine this medicine with other drugs as interaction is possible. The medicines you should be especially careful with include dexfenfluramine and fenfluramine – their combination with phentermine can lead to a fatal disorder - pulmonary hypertension. This is s prescription drug and it must not be used by people to whom it was not prescribed as it can form a habit. Once you started taking it do not discontinue the treatment, as this may lead to serious withdrawal symptoms, such as extreme tiredness and depression. Gradual withdrawal is recommended – contact your doctor to receive more detailed instructions.

If you are pregnant or breastfeeding do not start taking phentermine without previously consulting your health care provider, as it is not known whether it can affect the health of an unborn baby or pass into breast milk. Unless your doctor told you otherwise you need to take a pill of phentermine on an empty stomach with a full glass of water without breaking or crushing it. As this is a habit-forming stimulant the usual period of treatment does not exceed a few weeks.