Common Prescription
Weight Loss Medications

There was a time when available weight loss medications were few and far between. Because of this, the options for prescriptions were limited and the cost was expensive. Patients have different medical histories and health risks when it comes to drugs. Not everyone reacts the same way nor do they achieve the same exact results. They require specific medication that would be effective to their unique health factors.

Pharmaceutical innovations have changed the industry with newer weight loss prescriptions being approved by the Food and Drug Authority (FDA). Today, there are different kinds of weight loss medications that are prescribed to patients who have specific health conditions. The variety of weight loss drugs available to patients has also created a competition in the market which has driven down the price.

Common Prescription Weight Loss Medications


Brands: Contrave

This medication is a combination of two drugs: buproprion is an anti-depressant which also helps people to quit smoking, while naltrexone has been used to treat alcohol addiction.

Potential Effectiveness

This extended-formula drug signals the brain to lower the appetite and help avoid overeating. Bupropion-naltrexone also boosts metabolism. Patients expect to lose 5% of their weight after 12 weeks of using bupropion-naltrexone. During trials, this combination drug helped patients lose 11-22 lbs.

Side Effects

Patients who are prescribed this medication need to get their blood pressure checked regularly, as it is known to raise blood pressure. Other common side effects of bupropion-naltrexone include


Brands: Saxenda

Liraglutide is a daily shot that manages type 2 diabetes. It can be used long-term by patients. It reacts to gut hormones that stimulate satiation and decrease hunger.

Potential Effectiveness

This drug copies a hormone that sends a signal to the brain that the stomach is full to encourage patients to eat less. In 16 weeks, patients can expect to lose 4% of their weight. If this is not achieved, doctors will advise the patient to stop, as the drug may not be proven effective for that individual. Some patients who used this medication have lost 8-13 lbs. Those who have been prescribed higher doses have yielded better results.

Side Effects

Patients who take liraglutide have complained about nausea and even experienced some vomiting. Other side effects are diarrhea, constipation, and low blood pressure. There are also serious side effects such as increased heart rate, kidney disease, gallbladder disease, pancreatitis, and even suicidal thoughts.


Brands: Xenical, Alli

Xenical is the prescribed and stronger version of orlistat. Alli is the lower-strength version that can be obtained without a prescription. Both Xenical and Alli are approved for long-term use.

Potential Effectiveness

Orlistat works differently than other drugs mentioned on this list. This medication affects the way a body absorbs fat. It blocks a third of the fat from the food patients consume. Patients who use orlistat need to be on a low-fat diet before starting the medication. This helps minimize the side effects. This drug can also affect the absorption of vitamins A, D, E and K, so additional multivitamin supplements should be taken 2 hours before or after.

Side Effects

Orlistat can cause abdominal cramps, gas, and uncontrollable bowels. Side effects may get worse if the patient consumes high-fat food. There is no research that correlates this drug to liver damage, but a few patients have experienced liver injury while on Orlistat.



Brands: Adipex-P, Lomaira, Suprenza

Phentermine is an oral appetite suppressant that is approved for short-term use. It is the oldest and most widely used medication for weight loss control. A patient may be recommended to use this drug over the course of less than 12 weeks. Patients who take insulin may need their dosages adjusted if they are prescribed to use phentermine. It also acts like the stimulant drug amphetamine and therefore needs a special type of prescription from a medical professional.

Potential Effectiveness

This drug stimulates the central nervous system and helps signal the body that the stomach feels full. Patients who have used medication with phentermine lost an average of 17 lbs., with a significant reduction in blood sugar and cholesterol levels.

Side Effects

The side effects of using phentermine include unpleasant taste in the mouth, dry mouth, vomiting, constipation, and diarrhea. More serious side effects are heart palpitations, increased blood pressure, dizziness, tremor, chest pain, shortness of breath and restlessness. It can also cause insomnia, so it is not advisable to take this drug later in the evening. Phentermine is also not advised to be given to patients with glaucoma, hyperthyroidism, or a history of drug addiction.

Phentermine and Topiramate

Brands: Qsymia

This is another medication that combines two drugs: phentermine is a weight loss drug while topiramate is an anticonvulsant which treats headaches, migraines, or seizures. Qsymia contains low amounts of phentermine.

Potential Effectiveness

This combination drug helps patients burn calories, makes food taste less good and makes the stomach feel full. Patients may feel less hungry or feel full soon after a meal. Those who use this medication may lose an average of 5-10% of their body weight. If 12 weeks have passed with only less than 5% of the body weight lost, patients are advised to gradually discontinue the use of this medication.

Side Effects

Phentermine can cause side effects such as constipation, nervousness, tingling on the hands and feet, increased heart rate and blood pressure, and insomnia. Topiramate is highly discouraged for pregnant individuals since it increases the risk of birth defects.


Brands: Wegovy, Ozempic, Rybelsus

Semaglutide is a weekly shot used to help manage type 2
diabetes and obesity. Ozempic and Rybelsus are brands for type 2 diabetes medication that contain semaglutide. Wegovy is specifically used as a treatment for obesity.

Potential Effectiveness

This drug stimulates the production of insulin and helps lowers appetite. Wegovy is recommended to be taken long-term, preferably for the rest of the patient’s life. It has been found that when patients stop taking Wegovy, they regain the weight they lost.

Side Effects

Notable side effects of semaglutide are tiredness, headache, nausea and vomiting, stomach pains and diarrhea.


Brands: Imcivree

Setmelandotide is a daily shot only approved for individuals who have certain rare genetic deficiencies. These specific conditions are leptin receptor deficiency, pro-opiomelanocortin deficiency and proprotein subtilisin-kexin type 1 deficiency. These certain genetic conditions have been studied and associated to obesity. Patients ages six and up are only allowed to be given this medication.

Potential Effectiveness

This drug helps patients lose weight by reducing their hunger and making them feel full. Moreover, it burns calories while the body is at rest. It activates the MC4 receptor in the brain which is found insufficient in patients with the listed genetic conditions above.

Side Effects

Apart from injection site reactions, common side effects may include nausea, headache, stomach pain, diarrhea, vomiting, back pain, and fatigue. Some patients may also experience depression or notice some hyperpigmentation on their skin.


Brands: Mounjaro, Zepbound

Mounjaro is used to treat diabetes. It is not approved to be used as a weight loss medication. Zepbound is the brand prescribed to patients in need of losing weight. Both medications are taken as a weekly shot. The dosage of Zepbound is decreased or increased weekly depending on how patients react to it.

Potential Effectiveness
Tirzepatide are GLP-1 agonists that lowers blood sugar levels. This also helps promote weight loss by suppressing the appetite and changes the way the stomach absorbs food.
Side Effects

Patients who use medication containing tirzepatide may
experience stomach pain, diarrhea, nausea, vomiting,
constipation, and abdominal pain.


Brands: Plenity

Hydrogel is an oral capsule that is used to treat obesity. This is not considered a medication, but rather a medical device. Each capsule contains superabsorbent hydrogel particles made from organic chemicals which increases in volume after absorbing food and water in the stomach. It is not a food substitute since it has neither nutritional nor caloric value. It is removed from the body through bowel movement.

Potential Effectiveness

Plenity should be taken before a meal. Patients are encouraged to drink lots of water so that the hydrogel particles will absorb the water and food in the stomach during food consumption. The particles will increase in volume which makes the stomach feel full.

Side Effects

Allergic reactions, abdominal pain and diarrhea are some of the side effects patients may experience after using hydrogel.


Upcoming Weight Loss Prescriptions

As previously stated, more and more weight loss drugs are being developed to better address the unique health factors of each patient. With the approval of Eli Lilly and Company’s Zepbound (tirzepatide), patients will have more effective weight loss options available to them in the near future.

Here are some upcoming weight loss drugs that are still awaiting approval from the FDA
at the time of this writing:

• Retatrutide
• Danuglipron
• Amgen
• Bimagrumab

It is important that patients should know their potential risks to these weight loss prescriptions. Speaking with a health service provider and coming up with the right plan for weight management is the best way to address a patient’s individual needs.

Weight loss medication should not be considered the only cure for chronic weight problems. A
combination of a prescription with good diet and exercise is still the most effective way to achieve desired outcomes. This means that weight management is not just reliance on the effectiveness of medication alone, but it also requires a lifestyle change.

Written & Reviewed By
The Diet Pens Team

The Diet Pens Team is a dedicated group of healthcare enthusiasts, nutritionists, and local pharmacists committed to providing the latest and most accurate information about diet pens and weight management. Our team combines years of expertise in healthcare and nutrition with a passion for helping individuals achieve their health goals.

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