Adderall is now sold in either an immediate-release tablet or an extended-release capsule, marketed as Adderall XR (for "eXtended Release"). Doses for both immediate-release and extended-release form come in 5, 10, 15, 20, 25, and 30 mg increments. Adderall XR is also available in a 40 mg dosage.
Adderall XR utilizes the [[Microtrol]]® delivery system to achieve the extended-release mechanism. This delivery system incorporates two beads: the first type of bead dissolves immediately and the second type releases four hours later. Maximum plasma concentration is achieved in seven hours, compared to regular Adderall IR (immediate-release) which reaches maximum plasma concentration within three hours. As a result of its high bioavailability, Adderall XR's effectiveness is not altered by food absorption in the GI tract. However, tmax (mean plasma concentration) is prolonged by 2.5 hours (using a standard high-fat meal as the control). Acidic beverages should not be taken with Adderall XR as they alter the pH balance of the stomach.{{fact}}
