List of anorexiants: Uses, common brands, and safety info

Anorexiants, commonly known as diet pills, are medications used to help with weight loss. Many of these medications work as appetite suppressants and are similar to stimulants like amphetamines. This article will review anorexiants in detail, including uses, side effects, and other information. The table below contains a list of anorexiants for reference.

What are anorexiants?

Anorexiants, or anorectic drugs, are prescription medications used for weight loss. Single-ingredient anorexiants are similar to amphetamines and can have serious side effects, including the potential for abuse and dependence. Because of these risks, they can only be used for a short time. Today, safer options are available, so healthcare providers often avoid using single-ingredient anorexiants as a first choice of treatment. Instead, combination drugs like Qsymia or Contrave, which are FDA-approved for long-term weight management, are more commonly used—or other drugs like GLP-1 agonists (such as Wegovy) or GIP/GLP-1 agonists (such as Zepbound) may be considered.

How do anorexiants work?

The way each anorexiant works is outlined below in its individual section. Many anorexiants work by increasing neurotransmitters (chemical messengers) in the brain, such as norepinephrine and dopamine, and reducing appetite. However, some exceptions exist, such as Qsymia—which contains two active ingredients for an additional mechanism. Another exception is the combination drug Contrave, which combines an opioid antagonist and antidepressant and works on parts of the brain related to appetite regulation and reward. 

Note: In this article, when we discuss anorexiants, we are not referring to drugs such as glucagonlike peptide-1 (GLP-1) agonists like Ozempic and Wegovy, or GIP/GLP-1 agonists such as Mounjaro or Zepbound. 

What are anorexiants used for?

Each medication has its own list of FDA-approved uses, which will be outlined in the sections below. Generally, anorexiants are used for the treatment of obesity (body mass index, or BMI, of 30 or higher). In some cases, they can be used in overweight adults (BMI of 27 or higher) who have at least one weight-related health condition. Some anorexiants are only FDA-approved for short-term use (such as phentermine), while others (Contrave and Qsymia) can be used for long-term or chronic use. Typically, anorexiants are recommended in combination with lifestyle changes like diet and exercise, as recommended by a healthcare provider.

Anorexiants FDA-approved for short-term use

Adipex-P, Lomaira (phentermine)

The U.S. Food and Drug Administration (FDA) has approved phentermine for the short-term treatment of weight loss in people with an initial BMI of 30 or more (obesity). It can also be used in people with a BMI of 27 or more (overweight) who have other risk factors, such as Type 2 diabetes or high cholesterol. Phentermine is typically used along with lifestyle changes like diet and exercise. 

Phentermine is similar to amphetamine-type drugs, which are central nervous system (CNS) stimulants. Amphetamine medications are often used to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy, but as a side effect, people often have decreased appetite and weight loss. Phentermine works by increasing chemical messengers called norepinephrine, dopamine, and serotonin to a lesser extent. Phentermine also acts as an appetite suppressant by stimulating the part of the brain associated with satiety. Phentermine is generally prescribed for short periods because people tend to develop tolerance, which means they need higher doses of the medicine to get the same response.

Side effects of phentermine may include dry mouth, stomach problems like diarrhea or constipation, sexual problems, restlessness, dizziness, insomnia, mood changes, headache, high blood pressure, and heart problems, including increased heart rate.

You should not take phentermine if you:

• Are allergic to the active ingredient or any ingredient in the medicine

• Have a history of heart problems or cardiovascular disease, drug abuse, glaucoma, overactive thyroid, or agitated states

• Are pregnant or breastfeeding 

• Have taken a drug in the monoamine oxidase inhibitor (MAOI) drug class in the past 14 days

• Take other weight loss drugs (including prescription drugs, OTC medicines, or supplements)

Although phentermine is FDA-approved for short-term use, some guidelines support off-label long-term use of phentermine. This is because it is considered inexpensive and effective, with a low potential for addiction. Other guidelines recommend against using any of the short-term weight loss treatments. Guidelines for weight loss medications continue to evolve as new drugs are approved and more data becomes available.

Benzphetamine 

Benzphetamine is FDA-approved for short-term weight loss in people with a BMI of 30 or higher who have not responded to diet and exercise alone. It is typically recommended along with lifestyle changes. 

Benzphetamine, like phentermine, is a CNS stimulant. In the body, benzphetamine is converted to amphetamine. It increases levels of norepinephrine and, at higher doses, dopamine (and, at very high doses, serotonin). In addition to suppressing appetite, benzphetamine may also decrease the sense of smell and taste. Benzphetamine is generally prescribed for a short period due to the risk of developing tolerance. Benzphetamine has similar side effects and contraindications (reasons someone should not use this drug) as phentermine.

Diethylpropion

Diethylpropion is used for short-term weight loss in people with a BMI of 30 or more who have not responded to diet and exercise alone. It is typically used along with lifestyle changes. 

Like phentermine and benzphetamine, diethylpropion is a CNS stimulant similar to amphetamines. It is thought to work by stimulating the satiety center of the brain, as well as increasing norepinephrine. Because of the risk of developing tolerance, this medicine is generally prescribed for short-term use. Diethylpropion has similar side effects and contraindications to phentermine and benzphetamine.

Phendimetrazine 

Phendimetrazine is used for short-term weight loss in people with a BMI of 30 or more or a BMI of 27 or more who have at least one other weight-related medical condition and have not responded to diet and exercise alone. 

Phendimetrazine, like phentermine, benzphetamine, and diethylpropion, is a CNS stimulant. It increases norepinephrine and dopamine levels and suppresses the appetite by stimulating the satiety center in the brain. Because of the risk of tolerance, phendimetrazine is typically prescribed for a short time. Phendimetrazine has similar side effects and contraindications to phentermine, benzphetamine, and diethylpropion.

Anorexiants FDA-approved for long-term use

Contrave (bupropion/naltrexone)

Contrave is FDA-approved for long-term weight management in adults with a BMI of 30 or more and adults with a BMI of 27 or more with at least one weight-related medical condition. Contrave is typically recommended along with lifestyle changes like a reduced-calorie diet and increased physical activity. This medicine contains two active ingredients—naltrexone and bupropion extended-release (ER). 

The way Contrave works is not completely understood. Its ingredients, naltrexone (an opioid antagonist) and bupropion (part of the aminoketone antidepressant class of medications), are thought to work on parts of the brain related to appetite regulation and the reward system. 

Common adverse effects of this prescription medication include stomach problems like nausea, vomiting, and constipation or diarrhea. Other common side effects include headache, dizziness, dry mouth, and insomnia. Contrave has a black box warning, the most serious warning required by the FDA. Because it contains an antidepressant, there may be an increased risk of suicidal thoughts and behaviors in children, teenagers, and young adults. People of any age who take Contrave should be closely monitored for changes in mood and behavior or suicidal thoughts and behaviors. 

You should not take Contrave if you:

• Are allergic to bupropion, naltrexone, or any ingredient in Contrave

• Have uncontrolled high blood pressure

• Have a seizure condition

• Have an eating disorder such as anorexia or bulimia

• Are abruptly stopping the use of alcohol or certain medications, such as benzodiazepines (a type of anxiety medicine) or seizure medicines, including barbiturates

• Take any other medicines that contain bupropion, such as Wellbutrin SR or Wellbutrin XL

• Take opioid pain medications

• Have taken an MAOI in the last 14 days

Qsymia

Qsymia is FDA-approved for weight loss and long-term maintenance in adults and pediatric patients 12 years and older with obesity. It can also be used in overweight adults who have at least one weight-related health condition. 

Qsymia is a combination drug that contains two active ingredients: phentermine and extended-release topiramate (topiramate ER). We talked above about how phentermine works. The way topiramate works for weight loss is not completely understood, but it is thought to work by suppressing the appetite and helping with satiety through various mechanisms. 

Common side effects of Qsymia include dizziness, taste changes, insomnia, constipation, dry mouth, and numbness and tingling in the face, hands, arms, or feet. Qsymia has the same contraindications as phentermine because it contains phentermine as an active ingredient. Additionally, anyone who is allergic to topiramate should not take Qsymia.

Are anorexiants safe?

Recalls

No recalls have been found for these products.

Are anorexiants controlled substances?

The U.S. Drug Enforcement Administration (DEA) classifies controlled substance drugs into categories based on their medical use as well as their potential for abuse and dependence. 

• Phentermine, Qsymia, and diethylpropion are Schedule IV drugs. Schedule IV drugs have a low risk for abuse and dependence.

• Benzphetamine and phendimetrazine are Schedule III drugs. Schedule III drugs have a moderate to low risk for abuse and dependence. They have a higher risk than Schedule IV drugs.

• Contrave is not classified as a controlled substance.

How much do anorexiants cost?

The cost of a prescription will vary by drug, dosage, quantity prescribed, generic availability, and insurance coverage. You can contact your insurance provider for up-to-date coverage and out-of-pocket cost information. You can also use a SingleCare card to save significant money on your anorexiant prescription. Here are some examples:

• A one-month supply of brand-name Adipex-P without insurance costs around $107. You can use a free SingleCare discount and substitute generic phentermine to pay as low as $8 per month.

• A one-month supply of brand-name Qsymia 7.5/46 mg without insurance costs about $269 without insurance. Although there is no generic version available at this time, you can use a free SingleCare discount to pay as low as $174 per month.

• A one-month supply of brand-name Contrave costs about $832 without insurance coverage. There is no generic version available at this time, but you can use a free SingleCare discount to pay as low as $646 monthly.

Sources:

• Anorectic drugs: use in general practice, Drugs (1976)

• Diet pills (anorectics), Partnership to End Addiction

• Adipex-P, PDR

• Adipex-P, DailyMed (2024)

• Contrave, DailyMed (2024)

• Qsymia, DailyMed (2024)

• Depletite #2 (diethylpropion), PDR

• Diethylpropion, DailyMed (2024)

• Didrex (benzphetamine), PDR

• Benzphetamine, DailyMed (2023)

• Bontril PDM (phendimetrazine), PDR

• Phendimetrazine, DailyMed (2023)

• Drug scheduling, United States Drug Enforcement Administration

• A review of current guidelines for the treatment of obesity, The American Journal of Managed Care (2022)