INSPRA Safety Information
Important Safety Information
INSPRA is indicated to improve survival of stable patients with left ventricular
systolic dysfunction (ejection fraction ≤40%) and clinical evidence of congestive
heart failure after an acute myocardial infarction.
INSPRA is contraindicated in all patients with the following: serum potassium >5.5
mEq/L at initiation; creatinine clearance ≤30 mL/min; concomitant use with the following
potent CYP3A4 inhibitors: ketoconazole, itraconazole, nefazodone, troleandomycin,
clarithromycin, ritonavir, nelfinavir, or other drugs described in their labeling
as strong inhibitors of CYP3A4.
The principal risk of INSPRA is hyperkalemia. Hyperkalemia can cause serious, sometimes
fatal, arrhythmias. Hyperkalemia can be minimized by patient selection, avoidance
of certain concomitant treatments, and periodic monitoring until the effect of INSPRA
has been established. Patients who develop hyperkalemia (>5.5 mEq/L) may still
benefit from INSPRA with proper dose adjustment.
Patients with congestive heart failure post-acute MI receiving INSPRA who have renal
insufficiency (serum creatinine levels >2 mg/dL [males] or >1.8 mg/dL [females];
creatinine clearance ≤50 mL/min) or patients with diabetes, including those with
proteinuria, should be treated with caution, due to the increased risk of hyperkalemia.
Adverse events reported more frequently in patients treated with INSPRA than placebo
were hyperkalemia (3.4% vs 2.0%) and increased creatinine (2.4% vs 1.5%). Laboratory
measurements of serum potassium >5.5 mEq/L occurred in 15.6% of patients receiving
INSPRA vs 11.2% of patients receiving placebo. Laboratory measurements of serum
potassium ≥ 6.0 mEq/L occurred in 5.5% of patients receiving INSPRA vs 3.9% of patients
receiving placebo. Discontinuations due to hyperkalemia or abnormal renal function
were less than 1.0% in both groups. Hypokalemia occurred less frequently in patients
treated with INSPRA (0.6% vs 1.6%).