Selection of oral controlled-release drugs: a critical decision for the physician.

Controlled-oral release dosage formulations of medications have become relatively prevalent in medicine today because of their ability to reduce noncompliance and, perhaps, to increase efficacy. However, there are many patient- and drug-related factors that may present special problems in product selection. For example, interchange of controlled-release brands that may have different absorption characteristics can result in therapeutic failure and/or toxicity. Especially in light of recent events associated with Food and Drug Administration product reviews, this paper outlines concepts that will assist physicians in making informed decisions regarding generic substitution of oral controlled-release products.