Nitroglycerin: Immediate-release DynaCirc® (isradipine) has been safely coadministered with nitroglycerin.
Hydrochlorothiazide: A study in normal healthy volunteers has shown that concomitant administration of immediate-release DynaCirc® (isradipine) and hydrochlorothiazide does not result in altered pharmacokinetics of either drug. In a study in hypertensive patients, addition of isradipine to existing hydrochlorothiazide therapy did not result in any unexpected adverse effects, and isradipine had an additional antihypertensive effect.
Propranolol: In a single dose study in normal volunteers using immediate-release DynaCirc® (isradipine), co-administration of propranolol had a small effect on the rate but no effect on the extent of isradipine bioavailability. Significant increases in AUC (27%) and Cmax (58%) and decreases in tmax (23%) of propranolol were noted in this study.
Digoxin: The concomitant administration of immediate-release DynaCirc® (isradipine) and digoxin in a single-dose pharmacokinetic study did not affect renal, non-renal and total body clearance of digoxin.
Fentanyl Anesthesia: Severe hypotension has been reported during fentanyl anesthesia with concomitant use of a beta blocker and a calcium channel blocker. An increased volume of circulating fluids might be required if such an interaction were to occur.