20
Immunosuppressive
agents
Cyclosporine, tacrolimus RFB may allow concomitant use
of cyclosporine and a rifamycin;
monitoring of cyclosporine and
tacrolimus serum concentrations may
assist with dosing.
Corticosteroids Monitor clinically; may require 2- to
3-fold increase in corticosteroid dose.
Anticonvulsants Phenytoin, lamotrigine TDM recommended; may require
anticonvulsant dose increase.
Cardiovascular
agents
Verapamil, nifedipine,
diltiazem (a similar
interaction is also
predicted for felodipine
and nisoldipine)
Clinical monitoring recommended;
may require change to an alternate
cardiovascular agent.
Propranolol, metoprolol Clinical monitoring recommended;
may require dose increase or change to
an alternate cardiovascular drug.
Enalapril, losartan Monitor clinically; may require a
dose increase or use of an alternate
cardiovascular drug.
Digoxin (among patients
with renal insufficiency),
digitoxin
TDM recommended; may require
digoxin or digitoxin dose increase.
Quinidine TDM recommended; may require
quinidine dose increase.
Mexiletine, tocainide,
propafenone
Clinical monitoring recommended;
may require change to an alternate
cardiovascular drug.
eophylline eophylline TDM recommended; may require
theophylline dose increase.
Sulfonylurea
hypoglycemics
Tolbutamide,
chlorpropamide,
glyburide, glimepiride,
repaglinide
Monitor blood glucose; may require
dose increase or change to an alternate
hypoglycemic drug.
Hypolipidemics Simvastatin, fluvastatin Monitor hypolipidemic effect;
may require use of an alternate
antihyperlipidemic drug.
Table 8. Clinically Significant Drug–Drug Interactions
Involving the Rifamycins
a
(cont'd)
Treatment
