CYP2D6 substrates Bupropion

Bupropion is metabolized primarily by CYP2B6, and its metabolism may be altered by drugs such as cyclophosphamide, which is a substrate of 2B6. The major metabolite of bupropion, hydroxybupropion, is a moderate inhibitor of CYP2D6 and so can raise desipramine levels. Bupropion should be avoided in patients taking MAOIs. 

AMPHETAMINES BUPROPION 1. t plasma concentrations of these substrates, with risk of toxic effects 2. t risk of seizures. This risk is marked in elderly people, patients with a history of seizures, those with an addiction to opiates/ cocaine/stimulants, and those with diabetes treated with oral hypoglycaemics or insulin 1. Bupropion and its metabolite hydroxybupropion inhibit CYP2D6 2. Bupropion is associated with a dose-related risk of seizures. These drugs that lower seizure threshold are individually epileptogenic. They have additive effects when combined 1. Initiate therapy with these drugs, particularly those with a narrow therapeutic index, at the lowest effective dose. Interaction is likely to be important with substrates for which CYP2D6 is considered the only metabolic pathway (e.g. amphetamines) 2. Extreme caution. The dose of bupropion should not exceed 450 mg/day (or 150 mg/day in those with severe hepatic cirrhosis)... 

ESCITALOPRAM, FLUOXETINE, FLUVOXAMINE, PAROXETINE, SERTRALINE BUPROPION T plasma concentrations of these SSRIs, with risk of toxic effects Bupropion and its metabolite hydroxybupropion inhibit CYP2D6 Initiate therapy of these drugs at the lowest effective dose. Interaction is likely to be important with substrates for which CYP2D6 is considered the only metabolic pathway (e.g. paroxetine)... 

Drug-drug interactions The inhibitory effect of bupropion on CYP2D6 metabolism has been previously demonstrated in vivo, for example by inhibition of dextromethorphan metabolism (SEDA-30, 20). An in vitro study using desipramine as substrate has suggested that this effect is due to the metabolites erythrohydrobupropion and threohydrobupropion, which were much more potent inhibitors of CYP2D6 than hydroxybupropion or bupropion itself [71 ]. 

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