This disclosure relates to administration of a combination of: 1) about 100-110 mg, about 104-106 mg, or about 105 mg of
bupropion hydrochloride, or a
molar equivalent amount of a
free base form or another salt form of
bupropion; and 2) about 40-50 mg, about 44-46 mg, or about 45 mg of
dextromethorphan hydrobromide, or a
molar equivalent amount of a
free base form or another salt form of
dextromethorphan in certain patient populations, such as patients having moderate renal impairment, patients having mild or moderate hepatic impairment, patients receiving a concomitant strong CYP2D6 inhibitor, patients who are known CYP2D6 poor metabolizers, those in need of an NMDA
antagonist that does not cause dissociation, and those at risk of QT
prolongation.