In most cases, you should not cut, split or crush extended release medication. Doing so may cause the entire dose of the medication to be released at once, potentially increasing the risk of adverse events. However, Toprol XL (metoprolol succinate) is one of the few exceptions to the rule. Toprol XL may be safety cut in half due to the unique extended release mechanism the drug utilizes. The tablets come from the manufacturer "scored" down the middle to aide in spitting.
Cutting Toprol XL (Metoprolol Succinate) In Half
As stated, Toprol XL is one of the few extended release medications that is safe to cut in half. This is due to the extended release mechanism of the tablets. The actual active ingredient in Toprol XL tablets are encapsulated in "micropellets" that are evenly distributed throughout the tablet, as shown in the below image:
Source: Toprol XL Information
After taking a tablet by mouth, it rapidly dissolves, releasing hundreds of micropellets (<0.5 mm in diameter each) that are filled with medication (i.e. metoprolol succinate). Once these pellets reach the digestive tract, they slowly disintegrate and deliver the medication at a controlled rate for a 24 hour effect.
As the micropellets are evenly distributed in Toprol XL tablets and aren't disrupted when a tablet is cut, Toprol XL is safe to split. In fact, the tablets come scored from the manufacturer to ease splitting.