While diet and exercise play a central role in weight management, additional measures are sometimes needed for high-risk cases. Phentermine — a prescription weight loss aid — and the antidepressant fluoxetine may be prescribed for severe obesity or treatment-resistant weight problems when other methods have failed. When added to a healthy diet, phentermine and fluoxetine may be helpful for weight loss.
Phentermine is a stimulant drug from the phenethylamine and amphetamine classes. It is prescribed as a weight loss aid and was once part of the diet drug combination Fen-Phen. Because of the risk for abuse, phentermine is usually reserved for patients with severe obesity that has not responded well to other treatments. Fluoxetine is a medication used to treat depressive disorders. Occasionally, it is prescribed for weight loss, erectile dysfunction and eating disorders such as anorexia nervosa.
Fluoxetine is a Selective Serotonin Reuptake Inhibitor (SSRI) that works by preventing the reuptake of serotonin in nerve synapses, resulting in higher levels of the neurotransmitter in the brain. Because serotonin affects appetite, fluoxetine can sometimes cause modest weight loss as a side effect. Phentermine works by speeding heart rate and metabolism, helping the body burn calories more efficiently. It also has an appetite suppressant effect that can be helpful for controlling food cravings and managing portion sizes.
Both phentermine and fluoxetine can cause unwanted side effects in some users. Drug Information Online warns of the potential for interactions between the two drugs in the form of serotonin syndrome, a potentially deadly condition. Symptoms of serotonin syndrome include hallucinations, irritability, rapid heartbeat and coma.
Common side effects of phentermine include headache, hyperactivity, restlessness and insomnia. According to E Med TV, diarrhea, appetite loss, anxiety, weakness and nausea may occur in patients taking fluoxetine.
The safest and most effective method of weight loss is eating a healthy diet and exercising regularly. Only use phentermine and fluoxetine with a doctor's supervision, and follow dosing directions carefully. Avoid taking phentermine with other stimulants such as caffeine or amphetamines, as this increases the risk for serious side effects. Tell your doctor about any side effects you experience while taking phentermine and fluoxetine promptly to prevent complications.
Phentermine and fluoxetine are not a substitute for a healthy diet and exercise. If you experience persistent or severe side effects while taking these medications, seek immediate medical assistance.