Ritonavir, both at boosted doses and higher doses, decreases
bupropion levels, and reduced
efficacy might be expected. This is the opposite effect to that which was originally predicted.
The extent of reduction in
bupropion levels seen suggests that the dose of
bupropion might need to be doubled. It would seem prudent to start
bupropion at the recommended starting dose and titrate to effect. Nevertheless, because of the original
in vitro data, the UK manufacturers of
bupropion currently caution that the recommended doses should not be exceeded.