Welcome to Just Answer. I'm going to look up this dose for this guy here and get back to you. He again is eating and drinking well right now? No weakness, vomiting or collapse?
Ok. Always curious as to what the reasoning is. The minimum toxic dose (to see signs) for Bupropion is 10 mg / kg, and he would be at 9.6 mg / kg. This amount may cause sedation and lethargy. Larger overdoses may cause salivation, agitation, ataxia, tremors, and seizures.
Treatment of a toxicity is supportive and symptomatic. If he's just tired and quiet, I'd let him rest. At 6 hours, were past a point of inducing vomiting or giving charcoal. If the more serious signs develop, then he should be seen.