No clinically important interaction occurs between most
triptans and propranolol, but the
plasma levels of rizatriptan are almost doubled by propranolol.
If propranolol is also given the manufacturers recommend a dosage reduction to 5 mg of rizatriptan, with a maximum of two or three doses in 24 hours. In the UK it is additionally recommended that dosing should be separated by 2-hours, but the basis for this is unclear, as studies have found that this does not modify the interaction.