The manufacturer of
co-artemether notes that
in vitro data indicate that lumefantrine significantly inhibits CYP2D6. As a consequence, they contraindicate the use of
co-artemether in patients taking any drug that is metabolised by CYP2D6, and specifically name
flecainide.
These contraindications seem unnecessarily restrictive, especially as
flecainide is not contraindicated with other established inhibitors of CYP2D6. Until more is known, it would be prudent to closely monitor the effects of any CYP2D6 substrate in patients for whom
co-artemether is considered the antimalarial drug of choice.