Which Weight Loss Medications Work Best?

Phentermine, Tenuate (Diethylpropion)

These medications have the benefit of nearly 60 years of clinical experience (Phentermine was approved in 1959), low cost, and are very effective. We generally use them first-line for these reasons. They have a mild stimulant effect (not too unlike caffeine), so unless directed otherwise, take first thing in the morning. Side effects may include: dry mouth, constipation, elevation in heart rate or blood pressure, agitation and insomnia. Most side effects are minor and resolve as your body gets used to the new medication; however, if you experience severe side effects, please discontinue your medication immediately and let us know.

We recommend avoiding other stimulants (caffeine, Sudafed) while taking appetite suppressant medication.

Because they were approved so long ago at a time when it wasn’t recognized that obesity is a chronic problem, they were only studied for short-term use (12 weeks or less); however, with our current understanding of obesity, we recommend continuing these medications chronically.  It is important to note that use in this way is considered “off-label” and controlled studies to prove safety and effectiveness long-term have not been performed; however, our clinical experience in using these drugs in this is that the medications are both safe and effective when used chronically. A study of 14,000 patients found this to be effective and safe (Obesity, 2019), and it is consistent with recommendations published by both the Endocrine Society and the Obesity Medicine Association.

Finally, when you read about Qsymia (below), please note that this drug is approved for chronic use and contains Phentermine as one of its ingredients.


Contrave is a combination of 2 medications – bupropion and naltrexone. It works in two separate areas of the brain to control hunger and reduce cravings. Side effects may include suicidal thoughts and other neuro-psychiatric reactions, nausea, vomiting, headache, and insomnia. Most side effects are mild and go away quickly. It can’t be used if you are on narcotic pain medications. It also can’t be used if you have a history of seizure, or risk factors for seizure (including anorexia or bulimia, heavy alcohol use). It is approved for chronic use for appropriate individuals. Contrave is stocked at CNC for your convenience.


Qsymia is a combination of 2 medications – phentermine and topiramate. The phentermine is at lower dose than what we typically use with the older forms of phentermine, and the topiramate is time-released. This gives very good appetite control – the phentermine through the first half of the day, then the topiramate during the second half of the day. Side effects can include numbness or tingling in the hands, arms, feet, or face (paraesthesia); dizziness; changes in the way foods taste or loss of taste (dysgeusia); trouble sleeping (insomnia); constipation; and dry mouth. This drug can cause birth defects if a woman becomes pregnant while taking it; therefore, if you are of childbearing potential, special counseling is needed to determine if this is a safe choice. It is approved for chronic use for appropriate individuals.


Saxenda is a once daily injectable medication approved for the treatment of obesity. It is a synthetic analog of a hormone your gut produces in response to meals that tells your brain you shouldn’t be hungry any more. The main side effect is nausea, but this generally goes away as your body gets used to the medication. The drug can’t be used if you have a history of or are at risk for medullary thyroid carcinoma or acute pancreatitis. The same molecule, liraglutide, has been available for the treatment of type two diabetes since 2010 (brand name Victoza); however, the dose used for weight control is significantly higher. It is approved for chronic use for appropriate individuals. If you are interested in Saxenda, contact your health insurance carrier to see if you have coverage. Or, check www.SaxendaCoverage.com.

Successful Life Long Weight Loss is Possible!

For many patients losing weight or maintaining weight loss, controlling the diet can be difficult. Dieters often find themselves constantly dwelling on what they should and shouldn’t eat, and after trying to restrict calories all day, overeat at night. Appetite suppressant medications like Phentermine and Tenuate can be very helpful to keep the dieter on track and in control.

Phentermine and Tenuate (and the other weight loss medications listed above) are very safe medications for most individuals and have been approved by the FDA for use in weight loss for over 50 years.

Appetite suppressant medications are not appropriate for all dieters and will be prescribed only if deemed an appropriate treatment option by our medical staff.