The risk of seizure with Wellbutrin is 100%, but that is totally a dose-dependent effect. Literally, anybody will seize with bupropion, if they take too much. The issue is dose. It's always about dose.

I'm not trying to scare you. The subject has been fully explored, and the dose recommendations for depression and smoking cessation are derived with the seizure risk prominently considered. Here are the exact details.

If you were to create a graph showing the incidence of seizure against dose of Wellbutrin, you'd see a virtually flat line at barely above zero percent, below 300 mg/day. Between 300 mg and 450, the line starts to rise, but it's still only at 0.4% of all users by the time dose reaches that level. Between 450 and 600 mg, the line starts to rise more sharply, reaching around 4%. Above that, the risk of seizure exceeds the benefit of treatment. If you actually had data to complete the graph, you'd see that up above 5000 mg/day or so, the line reaches 100%. In other words, if you give every person a large enough dose of wellbutrin, they'll have a seizure. But, if you stay down at the lowest doses, the risk is really quite small. At 300 mg/day, the risk is about the same as from taking any other antidepressant drug.

From the drug monograph: "At doses of up to 300 mg/day, the incidence of seizures is approximately 0.1% (1/1000) but increases to approximately 0.4% (4/1000) at the recommended dose (for treatment of depression) of 400 mg/day of the sustained-release formulation or 450 mg/day of the immediate-release formulation. The risk of seizure also appears to be strongly associated with the presence of predisposing factors."

Note the issue of predisposing factors. There are certain health or physical factors that a doctor may decide make it more likely that an individual may seize. For those people, it's best to avoid potential triggers of seizure activity. That said, the risk from normal therapeutic doses of wellbutrin is really quite small.

Lar