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Comparison of Prescription Appetite Suppressants


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There are so many different appetite suppressants on the market that it can be difficult to know which is the best one for you. The truth is, everyone has different needs and every body works with medications differently, so it's worth it to do a little research to see what's available. 

We've compiled this guide to some of our most popular prescription appetite suppressants, along with dosage information and what you should know about each


Phentermine is one of the best-known appetite suppressants on the market. It works to trick your body into feeling full while also stimulating metabolism. 

It is a DEA Schedule IV drug, which means that it is a controlled substance but poses a low risk for abuse or dependence. 

Phentermine is best for short term use, and with diet and exercise is a great option to jump start weight loss and a healthier way of life. 

Phentermine Dosage

Phentermine IR is available in 37.5 mg tablets (which can be split in half and taken twice a day) as well as in 15, 30, and 37.5 mg capsules. 

Patients take Phentermine before breakfast most often, but it can also be taken an hour or two after breakfast. 



Qsymia is a combination of Phentermine and Topiramate, two weight loss medications that, together with a reduced calorie diet and exercise, can help patients lose weight. It's a popular option for those with weight-related health problems. 

Qsymia Dosage

There are separate dosages for Phentermine and Topiramate. 

  • Phentermine dosages can be 18.75, 30 or 37.5mg tablets
  • Topiramate dosages can be 25, 50 or 100mg tablets

Patients begin with 18.75 (Phentermine)/25 (Topiramate) mg once daily for up to 30 days. Then, for maintenance, patients follow a dosage of 30/50 mg once daily. The max dose is 37.5/100 mg once daily. Weaning protocol is required when discontinuing the max dose. 

Qsymia is taken once a day, in the morning. After 4 weeks, weight loss should be evaluated, with an increase to the next highest dose if the patient has not lost weight, up to the maximum dose. 



Phendimetrazine is chemically related to amphetamines and is a Schedule III drug. Therefore, patients should use caution and take only as prescribed by their doctor. 

It is used for short-term treatment of obesity, along with diet and exercise. It suppresses appetite and increases heart rate. 

Phendimetrazine ER Dosage

Extended release Phendimetrazine comes in just one dosage: a 105 mg capsule that is taken once a day, about 30-60 minutes before breakfast. 

Phendimetrazine IR Dosage (BONTRIL® PDM)

The Immediate Release version of Phendimetrazine is available in 35 mg tablets, which are taken 2 or 3 times a day.

For some patients, only a half tablet (17.5 mg) is needed. 



Benzphetamine is similar to Phendimetrazine in that it functions similarly, is a Schedule III drug, and is used for short-term treatment of obesity. The primary differences are in the potential side effects and drug interactions, so be sure to discuss these topics with your doctor. 

Benzphetamine IR Dosage

Available in a 50 mg tablet that can be cut in half, Benzphetamine's starting dose is 25-50 mg a day, with a maximum maintenance dosage of up to 150 mg a day. The 25-50 mg are typically taken once to three times per day. 



Diethylpropion is another Schedule IV drug with a relation to amphetamines. It is for patients with a BMI of 30 or higher, and it is, like the previous drugs we discussed, only used for a short period of time. It, too, increases heart rate and suppresses appetite, but its effectiveness can stop after a period of time. 

Diethylpropion comes in Immediate Release (IR) and Extended Release (ER) options


The IR version is a 25 mg tablet that is taken three times a day. The maximum dose is 100 mg per day. It is taken one hour before meals, and patients may be able to add an afternoon dose for night hunger. 


For extended release, Diethylpropion comes in a 75 mg tablet which is taken once a day in the morning. 


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TransformYou can help with all your medical weight loss needs! Contact us to learn more about these appetite suppressants and more. 

Check out this article on natural appetite suppressants.