2 DOSAGE AND ADMINISTRATION
2.1 Heart Failure Post-Myocardial Infarction
Initiate treatment at 25 mg once daily and titrate to the recommended dose of 50 mg once daily, preferably within 4 weeks as tolerated by the patient.
Once treatment with INSPRA has begun, adjust the dose based on the serum potassium level as shown in Table 1.
|Serum Potassium (mEq/L)||Dose Adjustment|
|<5.0||25 mg every other day to 25 mg once daily|
25 mg once daily to 50 mg once daily
|5.5–5.9||50 mg once daily to 25 mg once daily|
25 mg once daily to 25 mg every other day
25 mg every other day to withhold
|≥6.0||Withhold and restart at 25 mg every other day when potassium levels fall to <5.5 mEq/L|
The recommended starting dose of INSPRA is 50 mg administered once daily. The full therapeutic effect of INSPRA is apparent within 4 weeks. For patients with an inadequate blood pressure response to 50 mg once daily increase the dosage of INSPRA to 50 mg twice daily. Higher dosages of INSPRA are not recommended because they have no greater effect on blood pressure than 100 mg and are associated with an increased risk of hyperkalemia [see Clinical Studies (14.2)].
2.3 Recommended Monitoring
Measure serum potassium before initiating INSPRA therapy, within the first week, and at one month after the start of treatment or dose adjustment. Assess serum potassium periodically thereafter.
Check serum potassium and serum creatinine within 3–7 days of a patient initating a moderate CYP3A inhibitor ACE inhibitors, angiotensin-II blockers or non-steroidal-anti-inflammatories.
2.4 Dose Modification for Use with Moderate CYP3A Inhibitors
In post-MI HFrEF patients receiving a moderate CYP3A inhibitor (e.g., erythromycin, saquinavir, verapamil, and fluconazole), do not exceed 25 mg once daily. In patients with hypertension receiving a moderate CYP3A inhibitor, initiate at 25 mg once daily. For inadequate blood pressure response, dosing may be increased to a maximum of 25 mg twice daily [see Drug Interactions (7.1)].