Marked rises in statin
plasma levels have been seen when
lovastatin was given with
diltiazem, and when
simvastatin was given with
diltiazem or
verapamil. Isolated cases of rhabdomyolysis have been seen when atorvastatin or
simvastatin were given with
diltiazem or
verapamil. However, it seems that problems with combinations of
statins and
calcium-channel blockers are rare.
It has been suggested that treatment with a statin in those taking
diltiazem (and probably verapamil) should be started with the lowest possible dose and titrated upwards, or considerably reduced if either of these
calcium-channel blockers is started. The manufacturers recommend a maximum
simvastatin dose of 20 mg in patients taking
verapamil and 40 mg in patients taking
diltiazem. Patients should be told to be alert for any signs of possible rhabdomyolysis (i.e. otherwise unexplained muscle tenderness, pain or weakness or dark coloured urine).