The FDA approved phentermine appetite suppressants in 1959. This is a very long time for any medication. With over 50 million prescriptions written in the past 60 years in the US alone, it has proven to be a safe and effective weight loss medication. Contrary to popular advice from those who are not medical professionals, blood pressure and heart rate are actually not affected. Brand names for phentermine are Adipex-P® and Lomaira. Adipex-P is a longer-acting version taken in the morning. Lomaira is a short-acting version that one can take 30 minutes before meals. Phentermine is also available under its generic name.
HOW DOES PHENTERMINE WORK?
Phentermine is a sympathomimetic amine, also known as an “anorectic” or “anorexigenic” drug. According to the National Library of Medicine, phentermine’s primary mode of action is that it increases the body’s release of catecholamines. Specifically, it causes the release of epinephrine and norepinephrine, and possibly dopamine as well.
These catecholamines cause a decrease in appetite and an increase in energy expenditure by their influence on a variety of neurotransmitters and neuropeptides throughout the hypothalmus. When you are taking phentermine, you tend to feel less hungry but more energetic and alert. Increased energy expenditure will burn more calories. Weight loss results from a combination of these influences.
ARE THERE ANY SIDE EFFECTS?
The most common side effects reported in clinical trials were dry mouth, dizziness, insomnia, restlessness, irritability, nausea, vomiting, diarrhea, and constipation. Many of these side effects go away as we adjust to a dose that works for you and your body adjusts to the medication.
WHO CAN TAKE PHENTERMINE?
This medication is the most effective as part of a treatment plan that includes exercise, behavioral changes, and a low-calorie diet. We recommend it for people with a body mass index ≥ 30 kg/m2 or a body mass index ≥ 27 kg/m2 with medical issues such as diabetes and high cholesterol.
People with the following medical conditions should NOT take phentermine:
- A history of cardiovascular disease (hardening of the arteries, stroke, congestive heart failure, and/or moderate to severe high blood pressure)
- Overactive thyroid
- Renal impairment
- Hypersensitivity to stimulants
- People with a history of drug abuse or mental illness
- Women who are pregnant or nursing
- Anyone who is currently taking or has used a monoamine oxidase inhibitor drug (MAOI) within the past 14 days
Each individual needs to discuss the use of these medications with their personal physician to see which medications will be safe and effective.