Phentermine will help you to lose excessive weight if your doctor thinks it’s the drug you need. Because of its powerful effects and also a number of side effects possible in some rare cases phentermine is available by prescription and should be taken only by people to whom it was prescribed. Unless your health care provider recommended otherwise you are supposed to take phentermine three times a day about half an hour before meals or once a day in the morning. Depending on the form of phentermine you have been prescribed – extended-release capsules or tablets – you may be expected to follow a slightly different routine of taking it. The period of treatment depends on your condition and general health condition and usually does not exceed 6 weeks. While some tablets of phentermine can be crushed and even mixed with food, the extended-release tablets are not supposed to be chewed or crushed. To learn more about the form of phentermine you are going to take talk to your health care provider or pharmacist, or simply read the label of your medicine. While some side effects, such as dry mouth, constipation, diarrhea and unpleasant taste in your mouth can be ignored as long as they do not intensify with time, other more serious side effects should be reported to your health care provider as soon as possible, including dizziness, chest pain, tremor, increased blood pressure, restlessness, swelling in your limbs, insomnia and difficulty doing activities that you normally had no problem doing.