Bupropion (Wellbutrin): dosage, uses, side effects

Wellbutrin, generic bupropion, has been used to treat depression since the 1980s. In many ways, it’s unlike many of the other antidepressants available—it’s considered an “atypical antidepressant.” One of its differences is that bupropion can also help you quit smoking under the brand name Zyban. Keep reading to learn about bupropion’s uses, side effects, and more.

Bupropion is a prescription medication that has been used in the treatment of major depressive disorder since the 1980s. It is available as a generic drug but has also been sold under several brand names, including Wellbutrin SR, Wellbutrin XL, Zyban, Budeprion, Aplenzin, Forfivo XL, and Buproban.

Bupropion is considered an “atypical antidepressant” because it works differently than the typical antidepressant medications. Typical antidepressants include (Hirsch, 2020):

• Selective serotonin reuptake inhibitors or SSRIs:

  • fluoxetine

  • citalopram

  • escitalopram

• Serotonin-norepinephrine reuptake inhibitors or SNRIs

  • duloxetine

  • venlafaxine

• Tricyclic antidepressants

  • amitriptyline)

• Monoamine oxidase inhibitors (MAOIs)

Scientists do not know precisely how bupropion works, but it seems to affect the brain chemicals (neurotransmitters) norepinephrine and dopamine, rather than serotonin (Hirsch, 2020).

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Bupropion is approved by the U.S. Food and Drug Administration (FDA) to treat (FDA, 2017):

• Major depressive disorder (MDD): Also called unipolar depression, MDD is a mental health condition where people have symptoms of persistently sad moods, a lack of desire to do anything, a sense of hopelessness or guilt, low energy, poor appetite, and trouble concentrating. These feelings are more than just “feeling sad” and can disrupt a person’s ability to function (Bains, 2021).

• Seasonal affective disorder (SAD): People with SAD feel down, gloomy, or lethargic during the darker days of winter. These depressed feelings are worse than the “winter blues” and affect a person’s ability to do everyday activities (Munir, 2021).  

• Smoking cessation: Bupropion is effective at helping people quit smoking, especially when combined with other smoking cessation methods. It is not associated with weight gain, a common problem in smoking cessation, making it an appealing adjunct to your smoking cessation plan (Sealock, 2021). 

Sometimes healthcare providers use medications "off-label"—this means that the FDA hasn't approved the drug for that specific purpose. Examples of "off-label" uses of bupropion include (UptoDate, n.d.):

• Bipolar disorder

• Attention deficit hyperactivity disorder (ADHD)

• Sexual dysfunction that results from using other antidepressant medications, like SSRIs

The FDA has issued a boxed warning regarding bupropion: People taking bupropion have an increased risk of worsening depression as well as suicidal thoughts and behaviors, especially children, teenagers, or young adults. Families and caregivers should be aware of this risk and seek medical advice if they notice these changes. 

Common side effects of bupropion include (UptoDate, n.d.):

• Excessive sweating

• Weight loss

• Fast heart rate (tachycardia)

• Constipation

• Mental changes, like agitation and hostility

• Dizziness

• Trouble sleeping (insomnia)

• Headaches or migraines

• Dry mouth

• Nausea/vomiting

• Tremors

• Blurred vision

Serious side effects of bupropion may occur, including suicidal thinking and behavior, confusion, hallucinations (seeing or hearing things that are not real), irrational fears (paranoia), high blood pressure (hypertension), and seizures (UptoDate, n.d.). 

People with undiagnosed bipolar disorder may experience manic episodes as a possible side effect of taking bupropion (UptoDate, n.d.). 

Another possible adverse effect of bupropion is acute angle-closure glaucoma (a sudden spike in eye pressure) in people with narrow angles in their eyes (some people are born with this eye structure). This condition causes severe eye pain and may lead to permanent vision loss if not treated immediately (UptoDate, n.d.). 

Wellbutrin overdose may lead to seizures, high blood pressure, fast or irregular heartbeats, and death (Hirsch, 2020). 

As with most medications, you should not stop bupropion abruptly or without consulting your healthcare provider. Fortunately, unlike many other antidepressants, Wellbutrin withdrawal does not typically cause significant symptoms (UptoDate, n.d.)

There are several formulations of bupropion available:

• Bupropion hydrochloride oral tablet (immediate-release): 75 mg, 100 mg

• Bupropion hydrochloride extended-release 12-hour (sustained-release) tablet (Wellbutrin SR or Zyban): 100 mg, 150 mg, 200 mg

• Bupropion hydrochloride 24-hour extended-release tablets (Wellbutrin XL): 150 mg, 300 mg, 450 mg

• Bupropion hydrobromide 24-hour extended-release tablets: 174 mg, 348 mg, 522 mg

Your healthcare provider will adjust your dose of bupropion depending on your medical history, the condition being treated, and how you tolerate any side effects.

Only the extended-release 12-hour sustained-release tablets (brand name Zyban) are approved to aid with smoking cessation. You should start taking it one week before your target quit date and may need anywhere from 7–12 weeks to quit smoking successfully. 

Be sure to tell your healthcare provider about any other drugs you may be taking before starting bupropion.  

Bupropion is broken down by the liver, specifically by the CYP2B6 system. Medicines that affect this system can also change the activity of bupropion by changing its levels in the body or its overall effectiveness. Examples of medicines that may affect bupropion levels are ritonavir, lopinavir, carbamazepine, phenobarbital, and phenytoin. 

Bupropion can also change the effectiveness of other drugs (like venlafaxine, sertraline, fluoxetine, haloperidol, thioridazine, and metoprolol), and you may need a medication dose adjustment (FDA, 2017). 

Other drugs that can change the levels of bupropion in your body include HIV antiviral drugs (like ritonavir, lopinavir, and efavirenz) and anti-seizure drugs (like carbamazepine, phenobarbital, and phenytoin) (FDA, 2017). 

Serious potential drug interactions may occur if you take bupropion with monoamine oxidase inhibitors (MAOIs). You should not use bupropion within two weeks of taking MAOIs like phenelzine, tranylcypromine, isocarboxazid, and selegiline. Both bupropion and MAOIs increase norepinephrine and dopamine activity—using both drugs together can lead to severely high blood pressure or hypertensive crisis (Sabri, 2020).

Using bupropion with dopaminergic medications (drugs that increase dopamine levels in your system) significantly raises your dopamine levels and can lead to CNS (central nervous system) toxicity. Symptoms of CNS toxicity include restlessness, agitation, tremor, difficulty walking, and dizziness. Levodopa and amantadine are examples of dopaminergic medicines and are often used to treat Parkinson's disease. 

Certain medications raise the risk of seizures, especially if you combine them with bupropion. Examples include antidepressant medications, antipsychotics, theophylline, or systemic corticosteroids. Similarly, you should avoid drinking alcohol while taking bupropion as it can increase your risk of seizures (UpToDate, n.d.)

This list does not include all possible drug interactions with bupropion, and others may exist. Check with your pharmacist or healthcare provider for more information.

According to the FDA, bupropion is Pregnancy Category C; this means there is not enough data to say whether or not bupropion is safe during pregnancy. It does cross the placenta and enters the breast milk. Therefore, it’s important to talk to your healthcare provider and consider both the potential benefits to the mother as well as the risks to the fetus if you are pregnant or breastfeeding (UpToDate, n.d.).

If you have a seizure disorder, you should not take bupropion because it can increase your risk of seizures. Likewise, you should not take this drug if you have a medical condition that increases your risk of seizures. These include eating disorders like anorexia or bulimia, severe head injury, or withdrawal from benzodiazepine or alcohol intoxication. 

Some people taking Wellbutrin have reported testing positive for amphetamines on urine drug tests because bupropion is chemically related to amphetamines.

Lastly, people with severe allergic reactions to bupropion (e.g., rash, itching, hives, chest pain, trouble breathing, etc.) should not take bupropion.