by Nicole Evans M.D.

Created on: March 25, 2010   Last Updated: March 28, 2010

Wellbutrin SR and Wellbutrin XL are prescription medications used in the treatment of major depressive disorder as well as several other psychological conditions.  The generic name for Wellbutrin is Amfebutamone, also called Bupropion.  This means that both Wellbutrin SR and Wellbutrin XL contain the same basic drug.  However there are important differences between these two formulations of Wellbutrin.

Wellbutrin SR is a form of Bupropion that is specifically known as a sustained release hydrochloride salt.  Wellbutrin SR is packaged in an extended release, film-coated tablet.

Wellbutrin SR is initially started in a patient by taking a tablet by mouth once daily in the morning.  The dose is then increased to twice daily after the fourth day, one tablet in the morning and one tablet in the evening. 

The target dose for Wellbutrin SR is 300mg per day with a maximum dose of 400mg per day.  Any dosages greater than 150 mg are always administered as divided doses twice daily.  Preferably 8 or more hours should separate the twice daily doses of Wellbutrin SR.

Wellbutrin XL is different than Wellbutrin SR.  Wellbutrin XL is an extended release hydrochloride salt.  Unlike Wellbutrin SR, Wellbutrin XL comes in an extended release tablet that does not dissolve.  This means that the shell of the extended release tablet (Wellbutrin XL) may be passed in the stool.

Wellbutrin XL is also dosed differently than Wellbutrin SR.  The XL preparation of Wellbutrin is taken by mouth once daily in the morning, with an interval of 24 hours separating the doses. The dose may be increased as early as day 4 after the initial dose, up to an ideal dose of 300 mg once a day.  The maximum dose of Wellbutrin XL is 450 mg a day.

Both Wellbutrin XL and Wellbutrin SR may be useful (alone or in combination with other antidepressants) in patients with depression that has not responded to other therapies. 

Wellbutrin, whether the XL or SR formula, is not recommended by for bulimia nervosa eating disordered patients.  This medication is contraindicated in bulimia nervosa because it is associated with seizures in purging bulimic patients.

Wellbutrin may, however, be useful as a therapeutic agent in individuals who are trying to quit smoking.  Any formulation of Wellbutrin may be used and these can be used alone or in combination with nicotine replacement therapy.

In addition, either the XL or SR forms of Wellbutrin may be used in people with bipolar disorder.  However, Wellbutrin is used only as a second-line agent when first-line agents for bipolar depression are ineffective or not tolerated.

Wellbutrin XL and Wellbutrin SR are different preparations of the same prescription antidepressant medication.  Work with your physician to determine which formulation is right for you.

Source:

Lexi-Comp Online. Accessed Mar 25 2010.

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