PA – prolonged action
RA – repeat action
SA – slow acting
SR – slow release, spaced release or sustained release
TR – timed release
XL – extended release
XR – extended release
Which acronym is used is a decision left up the the drug manufacturers. There are no rules specifying the use of any specific acronym. In fact, some extended-release medications don't use any acronym. For example, OxyContin is extended-release but has no acronym following it. So don't take for granted that your medication is not extended-release just because you don't see an acronym in the name. Be sure to read the information sheet your pharmacist gives you or ask your pharmacist if you have any doubts.
Q: How much total medication is actually in an extended-release tablet?
A: Whatever dosage is prescribed is the total amount contained in each tablet. A portion of that dosage will be released every few hours – exactly how much and how often will depend on the specific medication. As an example, a 20 mg extended-release tablet may contain two 10 mg doses that are released approximately six hours appart.
When filling out forms that ask what medications you are taking, list the dosage exactly as shown on your prescription bottle. Your doctor will know whether or not it is extended-release and what that means.
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Sources:
Schoenwald, R.D. (2000). Pharmacokinetic principles of dosing adjustments: understanding the basics. CRC Press.
River Pharmacy
https://www.riverpharmacy.com/frequentlyAskedQuestions.php?id=89
© Karen Lee Richards
Updated 3/24/09
