Wellbutrin SR vs. XL: 4 Differences to Consider
Key takeaways:
Wellbutrin SR and Wellbutrin XL contain the same active ingredient, bupropion. They both treat depression. And Wellbutrin XL is approved to prevent seasonal affective disorder.
A generic form of bupropion SR (formerly known as Zyban) is also approved to help people quit smoking.
Wellbutrin SR is released slightly faster in the body, but Wellbutrin XL lasts longer. That’s why Wellbutrin SR is usually taken twice a day. Wellbutrin XL is typically taken once every morning.
Wellbutrin SR and XL have similar side effects and drug interactions. But Wellbutrin XL may be less likely to cause insomnia.
Table of contents
Wellbutrin (bupropion) is a common medication prescribed to treat depression. In this article, we’ll focus on two long-acting versions: Wellbutrin sustained-release (SR) and Wellbutrin extended-release (XL). Keep in mind that these medications are not interchangeable.
When comparing Wellbutrin SR versus XL, there are a few differences to consider. You’ll want to know how quickly they work, how long they last, and how often to take them. Here, we cover four differences between these two medications, as well as their similarities.
1. You’ll absorb Wellbutrin SR quicker, but Wellbutrin XL lasts longer
Both Wellbutrin SR and Wellbutrin XL contain the same active ingredient: bupropion. They’re both considered extended-release medications. That means they both last longer than the immediate-release (IR) form of bupropion. But Wellbutrin SR is a sustained-release product, whereas Wellbutrin XL is a traditional extended-release product.
Wellbutrin SR is absorbed a little faster than Wellbutrin XL. It takes Wellbutrin SR about 3 hours to reach steady levels in your bloodstream, while Wellbutrin XL can take about 5 hours. Both medications are released more slowly into the body than bupropion IR. This may lead to fewer side effects.
Although it’s absorbed more slowly, Wellbutrin XL releases medication in the body for up to 24 hours. Wellbutrin SR only releases medication for up to 12 hours.
2. They have different FDA-approved uses
Both Wellbutrin XL and Wellbutrin SR treat depression. Wellbutrin XL is also FDA approved for seasonal affective disorder (SAD). This is a type of depression that people mainly experience in the fall and winter. A generic form of bupropion SR (formerly known as Zyban) is approved to help people quit smoking alongside treating depression.
We’ll focus on Wellbutrin products only in this article. But there’s another form of bupropion that’s similar to Wellbutrin XL, called Forfivo XL. It’s FDA approved for depression only.
Aplenzin is another bupropion medication. But instead of containing bupropion hydrochloride like Wellbutrin products and Forfivo XL, it contains bupropion hydrobromide. Aplenzin is approved to treat depression and prevent SAD.
3. You may need to take Wellbutrin SR more often than Wellbutrin XL
Since Wellbutrin XL can last up to 24 hours in the body, it's typically taken once a day only. Wellbutrin SR is generally taken twice a day. Wellbutrin SR doses should be taken at least 8 hours apart.
With both medications, you’ll typically start at a lower dose and your prescriber may increase it over a few days. You’ll typically take your Wellbutrin XL dose, and the first dose of Wellbutrin SR, in the morning.
Wellbutrin XL and Wellbutrin SR both come as tablets, but they come in different dosages. Wellbutrin SR is available as 100 mg, 150 mg, and 200 mg tablets. Wellbutrin XL is available in 150 mg and 300 mg tablets.
4. They may have different side effects
Wellbutrin XL and Wellbutrin SR have similar side effects, such as:
Tremors
Mood changes, including agitation and anxiety
Trouble sleeping (insomnia)
Dry mouth
Headache
Constipation
Dizziness
Increased sweating
Loss of appetite and weight loss
Nausea
Faster heartbeat
What does taking Wellbutrin feel like? Read first-hand accounts of what it feels like to take Wellbutrin for depression.
How does Wellbutrin work? Wellbutrin’s mechanism of action is different from that of other antidepressants. Here’s how it works in your body.
What are Wellbutrin’s side effects? Learn what side effects are possible when taking bupropion and when to seek medical care.
There is limited research to show whether these side effects are more likely with Wellbutrin SR or Wellbutrin XL. In general, the risks are similar. However, one study found that insomnia is less likely with Wellbutrin XL. So when comparing Wellbutrin XL versus Wellbutrin SR for their effects on sleep, it’s possible that Wellbutrin XL is a better choice.
Additionally, compared to antidepressants like selective serotonin reuptake inhibitors (SSRIs), Wellbutrin SR and Wellbutrin XL have a much lower risk of sexual side effects. Paroxetine (Paxil) is an example of an SSRI that can cause erectile dysfunction.
Serious risks
Wellbutrin SR and XL are generally well-tolerated. But in rare cases, serious risks can occur. Both medications can cause high blood pressure, worsen symptoms of mania in people with bipolar disorder, and trigger glaucoma in some people. They also both have a boxed warning (the strongest FDA warning) for suicidal thoughts and behaviors. This risk is higher for young adults under the age of 25. If you experience any sudden or extreme mood changes, or thoughts of harming yourself, seek immediate medical help.
Both medications can also raise the risk of seizures in some people. This is especially true if you take high doses or if you take other medications that raise your seizure risk. If you have a history of seizures, or you’ve had an eating disorder like anorexia or bulimia, your risk may also be higher. So let your prescriber know your full health history before starting any bupropion products.
Can you take Wellbutrin SR and Wellbutrin XL together?
No, these two forms of Wellbutrin aren’t typically taken together. The combination can increase your risk of side effects.
If you’re taking Wellbutrin XL or Wellbutrin SR and it doesn’t seem to be working, let your prescriber know. They may recommend increasing your dose, or switching you to another medication altogether. But keep in mind that antidepressants can take a couple months to start working when treating depression. Although you may see an improvement in some symptoms more quickly, full effects can take this long.
Do Wellbutrin SR and Wellbutrin XL have any similarities?
As we’ve discussed, Wellbutrin SR and Wellbutrin XL have a number of differences. But they’re more alike than they are different. Below, we’ll cover what these medications have in common:
They contain the same active ingredient. Both medications contain bupropion. They’re part of the same medication class called atypical antidepressants.
They work the same way. Wellbutrin products work by increasing the levels of certain neurotransmitters (chemical messengers) called norepinephrine and dopamine. This is thought to help treat symptoms of depression and reduce symptoms of nicotine withdrawal. Wellbutrin also blocks nicotine receptors (binding sites), making nicotine less pleasurable.
Both are available in generic form. Both Wellbutrin SR and XL come in more affordable generic versions. But it’s important to know that your prescription label could read “bupropion extended-release” for either of these. But it should also say “12 hour” or “24 hour” to let you know which version you have. Ask your pharmacist if you’re unsure which Wellbutrin generic is in your bottle.
They’re taken in a similar way. Wellbutrin SR and Wellbutrin XL can be taken with or without food. With both products, you should swallow the tablets whole. Don’t crush, split, or chew them. You’ll usually take Wellbutrin XL, or your first dose of Wellbutrin SR, in the morning. If you’re taking another dose of Wellbutrin SR later in the day, it should be at least 8 hours from your morning dose.
They have similar drug interactions. Since both medications contain bupropion as the active ingredient, they have the same drug interactions.
How to save on Wellbutrin SR and Wellbutrin XL
There are ways to save on Wellbutrin SR and Wellbutrin XL. GoodRx can help you navigate your options, which may include GoodRx discounts and copay savings cards.
Wellbutrin SR: You can pay as little as $9.30 for a 1-month supply of generic Wellbutrin SR with a free GoodRx coupon.
Wellbutrin XL: A 1-month supply of generic Wellbutrin XL costs as low as $9.60 with a GoodRx coupon. If you have commercial insurance, you can get brand-name Wellbutrin XL for as little as $5 per month with a manufacturer copay card.
Frequently asked questions
Yes, Wellbutrin SR and Wellbutrin XL can cause weight loss in some people. This is because boosting dopamine and norepinephrine levels may decrease your appetite.
Wellbutrin itself isn’t FDA approved for weight loss. But the main ingredient in Wellbutrin products — bupropion — is combined with naltrexone in a medication called Contrave. That medication is FDA approved for weight loss.
Wellbutrin may be used off-label for ADHD. It may be helpful for some people, but it’s not a first-choice (or even second-choice) medication for most people. But your prescriber may recommend it if you’ve tried other ADHD medications and they haven’t worked. They may also suggest trying it if you can’t take other ADHD medications due to your health history.
The bottom line
Wellbutrin SR and Wellbutrin XL contain the same active ingredient: bupropion. They’re both used to treat depression. A generic form of bupropion SR (previously known as Zyban) is approved to help people quit smoking. And Wellbutrin XL is FDA approved for seasonal affective disorder.
Wellbutrin XL is designed to slowly release medication over a 24-hour period, meaning you typically only need to take it once a day. Wellbutrin SR releases medication over a 12-hour period, so it’s recommended to take it twice a day in most cases (at least 8 hours apart).
When comparing Wellbutrin SR versus XL, side effects and interactions are similar. Talk to your prescriber about which option may be best for you.
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References
Bancos, I. (2022). Adrenal hormones. Endocrine Society.
Epic Pharma. (2024). Bupropion hydrochloride SR- bupropion hydrochloride tablet, extended release [package insert].
Gandotra, K., et al. (2021). Development of insomnia associated with different formulations of bupropion. The Primary Care Companion for CNS Disorders.
Major Pharmaceuticals. (2021). Bupropion hydrochloride XL- bupropion hydrochloride tablet, extended release [package insert].
PubChem. (n.d.). Bupropion. National Library of Medicine.
Robinson, J. D., et al. (2022). Bupropion XL and SR have similar effectiveness and adverse event profiles when used to treat smoking among patients at a comprehensive cancer center. The American Journal on Addictions.
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