These abbreviations all refer to modified-release medications designed to release the drug slowly into your body rather than all at once. SR (Sustained Release) releases the medicine gradually over several hours to maintain steady blood levels. ER and XR (Extended Release) mean the same thing; they release the drug even slower than SR, often allowing you to take it just once a day. The main goal for all three is to reduce how often you take your pills and minimize side effects. Crucially, never crush, chew, or split these tablets, as doing so can release the entire dose at once, which can be dangerous.