How do I convert a patient from propranolol (Immediate Release) IR to propranolol (Extended Release) ER?

Converting Propranolol IR to Propranolol ER

When switching from propranolol immediate-release (IR) to extended-release (ER/LA), use the same total daily dose but administer once daily instead of twice daily. 1, 2

Direct Conversion Strategy

The conversion is straightforward: propranolol ER is dosed at the same total daily milligram amount as propranolol IR, but given once daily rather than divided. 1

• If a patient takes propranolol IR 80 mg twice daily (160 mg total daily), convert to propranolol LA 160 mg once daily 1
• If a patient takes propranolol IR 40 mg twice daily (80 mg total daily), convert to propranolol LA 80 mg once daily 1

Critical Caveat: Retitration May Be Required

Propranolol ER should not be considered a simple mg-for-mg substitute despite using the same total daily dose. 2

• The extended-release formulation produces lower peak blood levels than IR formulation 2
• The kinetics differ substantially between formulations, with propranolol ER achieving peak levels at approximately 6 hours versus much earlier with IR 2
• Retitration upward may be necessary to maintain effectiveness, especially at the end of the 24-hour dosing interval 2

Monitoring After Conversion

Assess therapeutic effectiveness within days to weeks after switching, as the time needed for full response is variable. 2

• For hypertension: full response may range from a few days to several weeks 2
• Monitor blood pressure and heart rate at follow-up visits to ensure adequate 24-hour control 1
• If effectiveness wanes toward the end of the dosing interval, increase the dose rather than splitting to twice-daily administration 2

Dosing Range Reference

The usual dose ranges for propranolol in hypertension are 80-160 mg daily for both IR (divided twice daily) and LA (once daily), with some patients requiring up to 640 mg daily. 1, 2

Common Pitfall to Avoid

Do not abruptly discontinue propranolol during the conversion process. 1 Switch directly from the last IR dose to the first ER dose without a gap in therapy to avoid rebound hypertension or worsening angina.