OMA Logo

June 30, 2021

5 Common Weight Loss Medications & Their Side Effects

Share this post

Obesity Medicine Association logo

5 Commonly Used Weight Loss Medications

Medication for weight loss is a valuable tool to help lose weight and keep it off. For many patients it is the key to success where diet and exercise alone have not worked. There are hormones in the gut, brain, and intestines that control hunger and fullness. Medication works to suppress hormones that regulate fullness and cravings. It is a complex process and different drugs target different pathways. So having a medication that is individualized to your needs is important for successful outcomes.

If you are considering discussing medication with your provider, here is some information to help you understand whether you are qualified to take the medication. Eligibility is determined by your body mass index (BMI). BMI is determined by a formula utilizing your height and weight. (If you would like to know your BMI, you can go to for an Adult BMI Calculator.)

If your BMI is 27-29 and you have a chronic disease like high blood pressure, Type II diabetes mellitus, prediabetes, sleep apnea, or metabolic syndrome, you are eligible for medicine. People who have a BMI of 30 or above do not need to have a chronic disease associated with their BMI, because obesity is considered a chronic disease.

There are five medications that are commonly utilized. Keep reading for details and information about each medication.

1. Phentermine:

The oldest and most widely used medication is Phentermine. It has been around for 60 years. Phentermine was originally used as a short-term medication to jump start weight loss, but now newer medical guidelines have added it to long term therapy. Phentermine works at the brain level to decrease hunger, so you do not overeat. If you have hyperthyroidism, glaucoma, or heart disease or have had a stroke this medication is not appropriate for you and there are other medications that would be more suitable. Common side effects of phentermine include dry mouth, restlessness, insomnia, and constipation. On the positive side, dry mouth increases water intake. Another beneficial advantage to phentermine is its low cost.

2. Phentermine combined with Topiramate

The next medication is Phentermine combined with Topiramate, better known as Qsymia. This medication has similar side effects to phentermine including dry mouth, constipation/diarrhea, insomnia, dizziness or altered taste. It cannot be taken if you are pregnant. The benefit of Phentermine/Topiramate is that it there are two medications working together to decrease hunger and increase fullness. The cost of this medication is higher because it is a non-generic.

3. Bupropion/Naltrexone or Contrave

The third drug is Bupropion/Naltrexone or Contrave. This is another combination medication that can help with fullness and cravings. You cannot take this medication if you have a seizure disorder or take opioids for chronic pain. Side effects to be aware of include nausea, constipation/diarrhea, headache, insomnia, and dry mouth. For those who struggle with sugar cravings this medication is beneficial.

4 & 5. Liraglutide (Saxenda) & Semiglutide (Wegovy):

Liraglutide (Saxenda) and Semiglutide (Wegovy) are two medications which are injectable. Liraglutide is daily and Wegovy is weekly. They both increase satiety or fullness. The most common SE include nausea, vomiting, diarrhea, constipation, headache, dizziness, and low blood sugar in patient with diabetes’s. Some patients also experience fatigue and abdominal pain with Semiglutide. Semiglutide is the newest medication available, and the weight loss data look very promising at 15 % weight loss in about 50% of patients.

Weight loss is a journey to living a healthy life and medication is a tool. Weight loss medications can be helpful in promoting and maintaining weight loss. However, there are side effects, so consider discussing the pros and cons with your provider to find the right fit for your body. For help with finding a weight loss clinician, visit our clinician directory.