However, this age cohort doesn't apply to all drugs for all indications. For example, valproic acid and divalproex sodium have been studied for a number of indications, including partial seizures, bipolar disorder and migraine prophylaxis. The indication determines the age group studied. FDA has studied down to age 3 for partial seizures, down to age 10 for bipolar disorder and down to age 12 for migraine prophylaxis.
Although much of pediatric drug use still comes from off-label prescribing, recent legislation provides for the safe and effective development of drugs in pediatric populations. In 1994, the Pediatric Labeling Rule was issued. This rule permitted extrapolation of efficacy from well-controlled studies in adults to the pediatric population as long as the course of the disease and effects of the drug are expected to be the same.