Wellbutrin dosage, forms, and strengths

Wellbutrin is a brand-name prescription drug approved to treat adults with major depressive disorder (MDD). Wellbutrin XL (extended-release) is used for MDD and can also be used to prevent depressive episodes in people with seasonal affective disorder (SAD). Wellbutrin and its generic, bupropion hydrochloride, are also prescribed off-label for smoking cessation and to treat attention-deficit hyperactivity disorder (ADHD) in adults and children, antidepressant-induced sexual dysfunction, depressive episodes in adults with bipolar disorder, and obesity. Wellbutrin works differently than other antidepressants. Most antidepressants increase serotonin, a chemical neurotransmitter that passes signals between nerves in the brain. Wellbutrin works by increasing the levels of other neurotransmitters in the brain, namely norepinephrine and dopamine, allowing patients to better regulate their mood. 

Wellbutrin is available as a sustained-release (Wellbutrin SR) or extended-release (Wellbutrin XL) tablet. Generic bupropion is available in both formulations as well as an immediate-release formulation. Bupropion might also be sold under other brand names including Forfivo XL, Aplenzin (bupropion hydrobromide), and Zyban, which is indicated for smoking cessation. Zyban has recently been discontinued in the brand-name form, but is still available as generic. Wellbutrin SR is generally taken by mouth twice a day, while the extended-release (XL) format is usually taken once per day in the morning.

RELATED: What is Wellbutrin? | Get Wellbutrin discounts 

Wellbutrin SR forms and strengths

Wellbutrin SR is available as a tablet in three strengths. Wellbutrin XL comes in two dose strengths.

• Sustained-release tablets (SR): 100 milligrams (mg), 150 mg, 200 mg

• Extended-release tablets (XL): 150 mg, 300 mg

Wellbutrin SR and XL dosage for adults

Wellbutrin is FDA-approved to treat adults with major depressive disorder (MDD), seasonal affective disorder (SAD) (only Wellbutrin XL, not SR), and Wellbutrin SR is sometimes prescribed off-label for patients who are trying to quit smoking.

*off-label use

Wellbutrin dosage for major depressive disorder (MDD)

Wellbutrin is an antidepressant most commonly prescribed to treat major depressive disorder, a mental health condition that is diagnosed when symptoms of depression such as sadness, loss of enjoyment, suicidal thoughts, and other symptoms last for two weeks or longer. Wellbutrin raises the levels of two substances, norepinephrine and dopamine, that pass nerve signals in the brain. By rebalancing these neurotransmitters, the drug helps people better regulate their moods.

• Standard adult dosage for major depressive disorder: 150 mg Wellbutrin SR taken twice per day (300 mg daily); or 150 or 300 mg Wellbutrin XL taken once per day

• Maximum adult dosage for major depressive disorder: 200 mg Wellbutrin SR taken twice per day (400 mg daily) or 450 mg Wellbutrin XL taken once per day

Wellbutrin dosage for seasonal affective disorder (SAD)

Seasonal affective disorder (SAD) is a type of depression that recurs at certain times of the year, usually late fall or winter. It is no longer considered a separate mental health disorder but is now diagnosed as a major depressive disorder with a seasonal pattern. Wellbutrin XL (not Wellbutrin SR) is specifically indicated for this condition.

• Standard adult dosage for major depressive disorder with seasonal pattern: 150 or 300 mg Wellbutrin XL taken once per day

• Maximum adult dosage for major depressive disorder with seasonal pattern: 300 mg Wellbutrin XL taken once per day

Wellbutrin dosage for smoking cessation

The active ingredient in Wellbutrin, bupropion, is FDA approved to help people quit smoking. About one in five people taking bupropion for smoking cessation successfully break their smoking habit. Bupropion’s mechanism is not completely understood for smoking cessation. It is thought to weaken cravings by increasing dopamine in the brain, just as nicotine does. In addition, bupropion weakens the effects of nicotine, making smoking less pleasurable. 

Smoking cessation treatment typically lasts seven to 12 weeks. The patient begins taking bupropion one or two weeks before a target quit date.

• Standard adult dosage for smoking cessation: 150 mg Wellbutrin SR taken twice per day (300 mg daily) 

• Maximum adult dosage for smoking cessation: 300 mg per day

Wellbutrin dosage for children

The U.S. Food and Drug Administration (FDA) has not approved Wellbutrin or bupropion for use in children or adolescents. However, healthcare providers may prescribe Wellbutrin off-label to treat major depressive disorder in children 11 years and older or attention-deficit hyperactivity disorder in children 12 years and older. Adolescents 14 and older (and weighing more than 89 lbs) may be prescribed Wellbutrin off-label to help them quit smoking.

Wellbutrin dosage restrictions

Before taking Wellbutrin, talk to your doctor about your symptoms, medical conditions, and medical history. Also, tell your doctor about all of the medications you take, including prescription and over-the-counter drugs as well as vitamins or supplements. 

Wellbutrin may cause problems in people with pre-existing medical or physical conditions. Contraindications are conditions that make taking Wellbutrin too hazardous to take. Any history of allergic reactions to bupropion is a contraindication. Also, because of the increased risk of seizures, Wellbutrin is never given to people with a seizure disorder, a prior diagnosis of an eating disorder such as anorexia or bulimia, or anyone undergoing abrupt withdrawal from alcohol, barbiturates, benzodiazepines, or anticonvulsants. 

Wellbutrin should not be given within 14 days of drugs in the category known as monoamine oxidase inhibitors (MAOIs). Wellbutrin has other drug interactions as well. Your healthcare provider will review your medication list for potential drug interactions. 

Bupropion is broken down by the liver and then mostly excreted in the urine. Lower doses may be required for people with kidney problems (renal impairment) or liver problems (hepatic impairment).

• Renally impaired patients—Possible dose or dosing frequency decrease

• Hepatically impaired patients

  • Mild hepatic impairment: Possible dose or dosing frequency decrease

  • Moderate to severe hepatic impairment: Maximum dose of 100 mg per day or 150 mg every 48 hours

Wellbutrin dosage for pets

Neither Wellbutrin nor bupropion are used in animals or pets. Please do not give pets human medicines such as Wellbutrin. If an animal is exhibiting behavior or mood problems, a veterinarian can prescribe medications appropriate for the animal.

How to take Wellbutrin

Depending on the formulation and dosage prescribed, Wellbutrin is taken by mouth once or twice a day with or without food.

• Take this medicine as directed.

• Read all medication guides and instructions that come with this medicine. 

• Swallow the tablet whole. Do not crush, break, cut, or chew it. If you do, the medicine will be released into the body more quickly, raising the risk of adverse effects.

• Take Wellbutrin SR doses at least eight hours apart.

• Take Wellbutrin XL in the morning. Doses should be spaced at least 24 hours apart.

• It may take several weeks before this medicine begins to show significant results. Give the medicine time to work. 

• Store the medicine in a closed container at room temperature (68° to 77°F) protected from heat, light, and moisture. Keep out of the reach of children and pets.

Wellbutrin dosage FAQs

Wellbutrin SR vs. Wellbutrin XL: What’s the difference in doses? 

Wellbutrin is available in two formulations: Wellbutrin SR (sustained-release) and Wellbutrin XL (extended-release). In addition, generic bupropion is available in an immediate-release formulation (bupropion IR), sustained-release formulation (bupropion SR), and extended-release formulation (bupropion XL). 

After a gradual dose increase, immediate-release bupropion is generally taken in three daily doses spaced six hours apart. Wellbutrin SR is usually taken in two daily doses spaced at least eight hours apart, and Wellbutrin XL is taken in the morning as a single dose. All formulations of Wellbutrin are increased gradually to lower the risk of seizure.

How long does it take Wellbutrin to work?

It may take several weeks for Wellbutrin to have a significant effect on depression, but many people will experience some improvement in symptoms in the second week of treatment.

How long does Wellbutrin stay in your system?

With a half-life of 14 hours for a single dose and an average of 21 hours when taken continuously day after day, bupropion can take at least three to four days to be cleared from the body. However, the body metabolizes bupropion into three substances that work just like bupropion. These metabolized versions of bupropion are about 20% to 50% as powerful as Wellbutrin and account for much of the therapeutic effects of Wellbutrin. These substances have half-lives of 20 to 37 hours. When Wellbutrin is taken continuously, the concentration of those substances in the blood soars to 1.5 to 7 times the concentration of bupropion in the blood. The effects of Wellbutrin, then, can last for several days after the last dose is taken.

What happens if I miss a dose of Wellbutrin?

A missed dose should be skipped. This applies to both formulations of Wellbutrin. If a dose is missed, wait until the next scheduled dose and take a regular dose at that time. Taking a missed dose will raise the risk of side effects such as seizures.

How long can you take Wellbutrin?

Antidepressant therapy typically takes four to six weeks to begin to relieve the symptoms of depression. However, to prevent a recurrence, antidepressants need to be taken daily for six to nine months. In many cases, patients may require a year or many years to a lifetime of continuous treatment. If Wellbutrin is prescribed for smoking cessation, treatment generally lasts seven to 12 weeks.

How do I stop taking Wellbutrin?

Don’t stop taking Wellbutrin until talking to a medical or mental health professional. Sudden discontinuation of Wellbutrin can provoke withdrawal symptoms. Your healthcare professional will advise you on a tapering schedule.

There are, however, many good reasons why people stop taking Wellbutrin, including allergic reactions or drug interactions. Some people may not be able to bear common side effects of Wellbutrin such as headache, constipation, or dry mouth. Other people may experience more serious side effects that demand the medicine be stopped immediately such as seizures, angle-closure glaucoma, dangerously high blood pressure (hypertension), irregular heartbeat, mania, or psychosis. Some young adults may experience a worsening of depression and suicidality, so they may be taken off Wellbutrin.

For smoking cessation, the only available alternative drug to bupropion besides nicotine is Chantix (varenicline). Chantix works by blocking nicotine’s effects in the brain, making smoking less pleasurable.

What is the maximum dosage for Wellbutrin?

The maximum daily dose of Wellbutrin SR should not exceed 400 mg for depression, or 300 mg for smoking cessation. The maximum daily dose of Wellbutrin XL is 450 mg per day for depression or 300 mg per day for depression with seasonal patterns.

Is it safe to take Wellbutrin during pregnancy?

Bupropion has not been shown to cause birth defects or miscarriages, however, there is inconclusive data about heart problems to the unborn baby. Therefore, pregnant women should get medical advice before taking Wellbutrin. If you already take Wellbutrin and find out that you are pregnant, contact your healthcare provider for medical advice.

Healthcare providers will be cautious about prescribing Wellbutrin to women who are breastfeeding. Bupropion and its active metabolites are present in human milk, so there’s a risk that a nursing infant may experience seizures. Women who are nursing should consult with a healthcare professional about taking Wellbutrin.

Can Wellbutrin increase the risk for suicidal thoughts and behavior?

Wellbutrin has a black box warning, which is the most serious warning required by the FDA. All antidepressants, including Wellbutrin, can increase the risk of suicidal thoughts and behavior. This is more common in children, adolescents, and young adults. However, patients of any age taking an antidepressant should be closely monitored for worsening of depression, mood changes, and suicidal thoughts and behaviors. Families and caregivers should monitor the patients and communicate any changes with the healthcare professional or seek emergency medical help if needed. 

Related resources:

• 15 years of clinical experience with bupropion HCl: From bupropion to bupropion SR to bupropion XL, Primary Care Companion to The Journal of Clinical Psychiatry

• Bupropion, StatPearls

• Bupropion compound summary, U.S. National Library of Medicine

• Bupropion prescribing information, U.S. National Library of Medicine

• Major depressive disorder with seasonal pattern, National Alliance on Mental Illness

• Steps following attainment of remission: Discontinuation of antidepressant therapy, Primary Care Companion to The Journal of Clinical Psychiatry

• The use of bupropion SR in cigarette smoking cessation, International Journal of Chronic Obstructive Pulmonary Disease

• Wellbutrin SR, Epocrates

• Wellbutrin SR prescribing information, U.S. National Library of Medicine

• Wellbutrin XL prescribing information, U.S. National Library of Medicine