In some patients Pemoline is suspected of causing hepatotoxicity, so regular liver tests are performed on those treated with it. Since receiving FDA approval in 1975, it has been linked with 21 cases of liver failure, of which 13 resulted in liver replacement or death. In 2005, the Food and Drug Administration (FDA) withdrew approval for pemoline due to pressure from certain public advocacy groups, including Public Citizen. The medication was used by an estimated 10,000 Americans afflicted with narcolepsy. A more potent analogue of pemoline, 4-methylaminorex has appeared as a black market drug with abuse potential similar to methamphetamine.
In March 2005, Abbott Laboratories (Cylert marketer) had discontinued the production of Cylert arguing economic reasons.
