The use of bupropion (BUP) involves a higher seizure risk than the use of other antidepressants, limiting its dose and widespread use. The two reported cases document anticonvulsant-BUP drug interactions through plasma levels. Carbamazepine appeared to decrease the plasma BUP to nondetectable levels, while hydroxybupropion was found at very high levels. Data presented suggest that BUP may increase sodium valproate levels. Conclusions from these case reports are tentative, pending further study. Monitering of BUP and its metabolites may ultimately prove useful in guiding clinicians dosing decisions, especially when mood stabilizers are combined with other psychotropic drugs in refractory bipolar patients.