Can you take phentermine and wellbutrin together for weight loss?

In this article:

• Can you take phentermine and Wellbutrin together for weight loss?
• What you should know about taking Wellbutrin and phentermine together
• Side effects of phentermine and Wellbutrin
• Phentermine and Wellbutrin contraindications
• Phentermine vs. Wellbutrin: Comparison

In this article

• Can you take phentermine and Wellbutrin together for weight loss?
• What you should know about taking Wellbutrin and phentermine together
• Side effects of phentermine and Wellbutrin
• Phentermine and Wellbutrin contraindications
• Phentermine vs. Wellbutrin: Comparison

Around 65% of adults in the United States say willpower alone is not enough to lose weight and keep it off with lifestyle changes, according to a Pew Research survey from 2024. That means there are millions of people looking to weight loss drugs for help. One such drug is phentermine (brand name: Adipex). If you’re taking Wellbutrin (bupropion) for depression and are considering weight loss medication, you may wonder whether phentermine is safe. 

Here’s what you should know if you’re considering taking both medications together. 

Can you take phentermine and Wellbutrin together for weight loss?

“It is not recommended to combine phentermine and Wellbutrin together for weight management because there is a drug-drug interaction between the two agents,” say Diana Roman, Pharm.D. and Miriam B. Morkos, Pharm.D. of Marshall B. Ketchum University.

More specifically, “Wellbutrin is associated with an increased seizure risk and should not be combined with other agents that may increase seizure risk, such as phentermine.” It can also cause a condition called serotonin syndrome, which can be potentially life-threatening.

The problem for some people is that obesity and depression may occur simultaneously. Studies have demonstrated a reciprocal connection between major depressive disorder and weight gain. In fact, people with obesity have a 55% higher chance of developing depression, while people diagnosed with depression have a 58% higher chance of developing obesity, according to a study from 2020. 

But according to Hannah Cohan, a board-certified nurse practitioner with the Medical Offices of Manhattan, “It’s safer to explore other weight loss options, such as Zepbound (tirzepatide) or Ozempic (semaglutide), which can be used alongside Wellbutrin without the same risk of serotonin-related complications.” Qsymia (phentermine/topiramate) and Contrave (bupropion/naltrexone) without Wellbutrin may be safer options purely for weight management.

RELATED: Contrave vs. phentermine

Some people actually report weight loss while taking Wellbutrin, so if you give it some time, you may find that phentermine isn’t necessary. Regardless, it’s extremely important to consult a healthcare provider about the best options for any specific case of obesity or depression. And “if a decision is made by a provider to combine the two agents, it is important to exercise caution and monitor therapy,” say Drs. Roman and Morkos.

What you should know about taking Wellbutrin and phentermine together

Even though there are specific instances when healthcare providers might prescribe Wellbutrin and phentermine together, they’re usually not combined. That’s because they can have some fairly serious drug interactions. These include:

• Increased risk of seizures: Wellbutrin’s drug label includes a warning that the drug is associated with seizures in 0.4% of people who take 450 mg per day—and that can increase tenfold for people who take 600 mg per day. Phentermine can also cause seizures, so taking them together increases the risk, especially for anyone who has a preexisting seizure disorder.
• Serotonin syndrome: “Wellbutrin works by increasing dopamine and norepinephrine levels in the brain, but can also affect serotonin indirectly,” Cohan says. “On the other hand, phentermine is an appetite suppressant that works by increasing the release of norepinephrine and inhibiting serotonin uptake. When combined, the risk of serotonin syndrome, a potentially life-threatening condition, increases, as both medications can influence serotonin levels in the brain.”
  Serotonin might be the body’s “feel good” chemical, but serotonin syndrome may cause nausea, vomiting, diarrhea, and tremors when it’s mild or high blood pressure, racing heart rate, seizures, and fainting when it’s more severe.

This is why it’s absolutely crucial to only take phentermine and Wellbutrin together if a healthcare provider has prescribed it and they’re monitoring your condition. Always consult with a healthcare provider about any medications or supplements you’re currently taking before beginning treatment, and always follow their instructions exactly.

What about dosages?

Most of the time, patients will not take these medications together. In those cases, the typical phentermine dosage is 15–37.5 mg per day. The standard dosage for Wellbutrin SR is 150 mg twice daily or 150–300 mg once daily (in the morning) for the extended-release Wellbutrin XL. The exact dosage a healthcare provider prescribes will depend on the patient’s specific condition, concurrent medications, medical history, and more.

Side effects of phentermine and Wellbutrin

Keep in mind that the risk of certain side effects of phentermine and Wellbutrin may be amplified if you take them together. It’s good to evaluate each drug’s adverse effects too, since some of them might be deal-breakers. For example, dry mouth, insomnia, headaches, and constipation are common side effects of both Wellbutrin and phentermine.

Phentermine and Wellbutrin contraindications

There are certain people who—because of an existing condition, other medications, allergies, or life circumstances—shouldn’t take a medication. For example, Wellbutrin is contraindicated for anyone who is:

• Diagnosed with a seizure disorder
• Taking other drugs that contain bupropion
• Diagnosed with bulimia or anorexia nervosa
• Undergoing an abrupt discontinuation of alcohol or sedatives
• Taking a monoamine oxidase inhibitor (MAOI) or has taken one within 14 days
• Allergic to bupropion

Phentermine is contraindicated for anyone who has or is:

• A history of heart disease or heart failure
• Taken a monoamine oxidase inhibitor (MAOI) in the past 14 days
• Hyperthyroidism
• Glaucoma
• Agitation
• A history of drug abuse
• A hypersensitivity to the sympathomimetic amines
• Pregnant or breastfeeding

Other warnings

Wellbutrin has a boxed warning, also called a black box warning, because of its potential for suicidal thoughts and behavior—especially in children, teenagers, and young adults. Wellbutrin’s label also warns of high blood pressure and seizures and recommends prescribing with caution for anyone who has renal or hepatic impairment. Alcohol may also interact with Wellbutrin, and the effects it can have on pregnancy are unclear.

But phentermine has its own set of warnings. It’s “a sympathomimetic agent chemically related to amphetamines, a drug known for its high abuse potential. Consequently, prolonged use of phentermine may increase the risk of developing drug dependency,” Drs. Roman and Morkos say. That’s why the Drug Enforcement Administration has classified it as a Schedule IV controlled substance. Plus, it may also cause primary pulmonary hypertension or valvular heart disease, which is why people with existing or previous cardiovascular conditions should avoid it. The drug label also advises against drinking alcohol while taking phentermine and says it may impair the ability to drive or operate machinery.

Average cost

If your healthcare provider gives you a choice between these prescription drugs—and the side effects, contraindications, and warnings aren’t an issue—then it might come down to price. Fortunately, neither drug is particularly pricey, and there are some steep discounts available.

The average out-of-pocket cost of phentermine is $51 for 30, 37.5mg tablets, while the average cost of Wellbutrin SR is $558 for 60, 150 mg tablets. But with SingleCare coupons, you can get a 30-day supply of phentermine for as low as $8, or a 30-day supply of generic bupropion SR for as low as $4.

Phentermine vs. Wellbutrin: Comparison
	Phentermine	Wellbutrin (bupropion)
Drug class	Anorectic	Antidepressant
Standard dosage and forms	15–37.5 mg once per day	Wellbutrin SR: 150 mg twice daily Wellbutrin XL: 150–300 mg once daily (in the morning)
Side effects	Dry mouth Insomnia Headaches Dizziness Constipation	Agitation Dry mouth  Insomnia Headache Nausea/vomiting
Risks/restrictions to consider	May lead to abuse or dependence Increased risk of hypoglycemia Increased risk of cardiovascular issues	Increased risk of suicidal thoughts/behaviors Increased risk of seizures Increased risk of high blood pressure
Average cost without insurance*	$51 for 30, 37.5mg tablets	$558 for 60, 150 mg tablets of brand-name Wellbutrin SR; $103 for generic bupropion HCL ER (SR)
SingleCare cost*	Get coupon	Get coupon
Learn more	More phentermine details	More Wellbutrin details

*Cost at the time of publication. Drug prices fluctuate and vary by location.

Bottom line

Taking phentermine with Wellbutrin is rarely a safe option since it can increase the risk of seizures and serotonin syndrome. But for certain people who have both major depressive disorder and obesity, this combination might be viable. Just be sure to consult your healthcare provider about your options, and always follow their directions exactly when taking either or both of these drugs for obesity management.