Wellbutrin® Dosage Guide: Ranges, Side Effects, and Safety

How Wellbutrin® Works

Wellbutrin® is the brand name for bupropion, an antidepressant classified as a norepinephrine-dopamine reuptake inhibitor (NDRI). 

Unlike SSRIs, which target serotonin, Wellbutrin® works by increasing the activity of norepinephrine and dopamine in the brain—two neurotransmitters closely linked to mood, motivation, and focus. 

In fact, this medication is FDA-approved to treat major depressive disorder (MDD) and seasonal affective disorder (SAD). Under a separate brand name, Zyban®, it’s also approved as a smoking cessation aid. 

However, some providers prescribe it off-label for conditions such as ADHD and antidepressant-related sexual dysfunction. But one thing that sets Wellbutrin® apart from many other antidepressants is its side effect profile. According to research, it’s generally associated with a lower risk of sexual dysfunction and weight gain compared to many SSRIs.

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Wellbutrin® Dosage Range by Condition

Wellbutrin® comes in three formulations, and the one you’re prescribed directly affects how often you take it and what dosage range applies:

• Immediate-release (IR): Taken 2 to 3 times per day.
• Sustained-release (SR): Taken twice daily, about 8 hours apart.
• Extended-release (XL): Taken once daily in the morning.

As noted above, bupropion is FDA-approved to treat major depressive disorder (MDD) and seasonal affective disorder (SAD), and under the brand name Zyban®, it is also approved as a smoking cessation aid. So, what dosage range is typical for these conditions or circumstances?

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Depression (SR and XL)

For Wellbutrin® SR, the typical starting dose is 150 mg once daily in the morning. After about three days, your provider may increase this to 150 mg twice daily. If your symptoms haven’t improved after several weeks, the dose can go up to a maximum of 400 mg per day (200 mg twice daily). 

For Wellbutrin® XL, the starting dose is also 150 mg once daily. After four days, your provider may increase it to 300 mg once daily, which is the most commonly prescribed dose. If there’s no improvement after several weeks at 300 mg, the maximum dose is 450 mg once daily.

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Seasonal Affective Disorder (SAD)

Only Wellbutrin® XL is FDA-approved for SAD. The starting dose is 150 mg once daily, and after seven days, it may be increased to 300 mg once daily. 

Treatment usually begins in the fall before symptoms start and continues through the winter. Your provider will then most likely taper the dose in early spring to avoid abruptly stopping the medication.

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Smoking Cessation (Zyban®)

For smoking cessation, the SR formulation is used under the brand name Zyban®. It starts at 150 mg once daily for three days, then increases to 150 mg twice daily. Treatment typically lasts seven to 12 weeks, and you’ll usually set a quit date during the second week.

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How is Wellbutrin® Dosage Adjusted?

Wellbutrin® is titrated gradually, meaning the dose is increased in various steps over days or weeks. This approach helps your body adjust and reduces the chance of side effects. 

For the SR form, doses should be spaced at least eight hours apart. For IR, the gap should be at least four to six hours, with the last dose taken in the mid-afternoon to avoid sleep disruption. 

If you miss a dose, take it as soon as you remember. But don’t double up. For XL, if you miss a dose entirely, just skip it and take the next one at your usual time. For IR and SR, follow your prescriber’s instructions for missed doses to reduce your seizure risk.

Never adjust your Wellbutrin® dosage on your own. Increasing the dose without medical guidance raises your risk of side effects, including seizures.

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Wellbutrin® Side Effects

Most side effects are mild and tend to improve as your body adjusts to the medication. The most frequently reported side effects include:

• Dry mouth
• Insomnia or trouble sleeping
• Nausea
• Headache
• Constipation
• Dizziness
• Excessive sweating
• Tremor or shakiness
• Agitation or restlessness 

These are often more noticeable in the first week or two of treatment or after a dose increase.

While uncommon, some side effects require immediate medical attention. Contact your provider or seek emergency care if you experience:

• Seizures 
• Severe mood changes (including worsening depression or suicidal thoughts)
• Hallucinations, paranoia, or confusion
• Rapid or irregular heartbeat
• Signs of an allergic reaction (such as a rash, swelling, or difficulty breathing) 

On top of the above, Wellbutrin® carries an FDA black box warning about the potential for increased suicidal thoughts and behaviors in children, adolescents, and young adults. This doesn’t mean the medication causes these feelings in everyone, but it does mean close monitoring is important, especially early on.

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Other Important Safety Considerations

This medication is not recommended for people with a seizure disorder, a current or past diagnosis of anorexia or bulimia, or anyone going through alcohol or benzodiazepine withdrawal. These conditions can lower the seizure threshold and significantly increase the risk. 

It’s further not recommended to take Wellbutrin® if you’ve used a monoamine oxidase inhibitor (MAOI) within the past 14 days. This combination can cause dangerously high blood pressure. 

Zyban® contains the same active ingredient as Wellbutrin®, so you should also never take both at the same time.

Lastly, if you have any liver or kidney impairment, your provider may reduce your dose or prescribe it less frequently.

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Final Thoughts

Finding the right Wellbutrin® dosage is a gradual process, ultimately determined by your prescribing provider. It often depends on various factors such as your condition, medical history, and your response to the medication before making adjustments. 

The most important thing you can do is follow your prescribed dosage, be patient, and communicate openly with your provider about how you’re feeling along the way.