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What does XR or ER mean after a drug name?

Medically reviewed by Last updated on April 11, 2023.

Official answer


XR or ER is short for extended-release which means the pill is formulated so that the drug is released slowly over time.

This has the advantage of taking pills less often and there may be fewer side-effects as the levels of the drug in the body are more consistent in extended-release formulations.

Examples of extended-release drugs include:

Related: Medical Abbreviations on Pharmacy Prescriptions

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