In past generations, doctors often prescribed amphetamines such as Dexedrine to help people lose weight and feel more energetic. But modern medicine discourages the use of prescription amphetamines for weight loss and energy due to the risk of addiction. If you want to lose weight and gain more energy, you should speak to your doctor about prescription appetite suppressants that have amphetamine-like properties such as phentermine, diethylpropion or phendimetrazine, notes the National Institute of Diabetes and Digestive and Kidney Diseases.
Phentermine is the most commonly prescribed weight loss and energy pill in the United States and has been approved for medical use since 1959, according to the Mayo Clinic. Your doctor may prescribe generic phentermine or the brand name Adipex-P. But you must change your diet and exercise habits or risk regaining any weight lost once you stop taking phentermine. You may experience side effects such as increased blood pressure, constipation, dry mouth or dizziness after taking the drug.
Your doctor may prescribe diethylpropion on a short-term basis to help you lose weight and increase your energy, according to PubMed Health. This drug is also marketed under the brand names Durad, Tenuate and Tepanil. You should not take the medication for more than 12 weeks; most doctors prescribe it for shorter periods due to its habit-forming potential. You may experience side effects such as an unpleasant taste in your mouth, vomiting, increased urination, restlessness or anxiety after taking diethylpropion.
Phendimetrazine is another Food and Drug Administration-approved weight loss and energy pill available only by prescription, according to the National Institute of Diabetes and Digestive and Kidney Diseases. Like other appetite suppressants, you should not take the drug for more than 12 weeks at a time. You also risk suffering from side effects such as a false sense of well-being, irritability, dry mouth, an unpleasant taste in your mouth and trouble sleeping.
The Food and Drug Administration has banned sales of several once-popular weight loss and energy supplements. You should not take any pills consisting of fenfluramine, sibutramine, ephedra, ephedrine, ma huang, country mallow and heartleaf. All of these ingredients may cause severe and even fatal heart and lung damage in some dieters; substances such as ephedra become even more potentially dangerous when combined with caffeine. As of 2011, Food and Drug Administration officials were investigating the safety of bitter orange.