Pemoline

Pemoline is an oxazoline-ring CNScentral nervous system; the brain and spinal cord stimulant, structurally its own thing (related to compounds like thozalinone and fenozolone) and quite different from the amphetamines or methylphenidate. Its stimulant action is thought to run mainly through dopaminethe brain's 'reward / worth-chasing' chemical; drives motivation and focus: it modestly increases dopaminergic transmission, and unlike amphetamine it does this weakly and with minimal effect on peripheral sympathetic tone, which is why it was marketed as having relatively little cardiovascular or blood-pressure activity ^[5][6]. Early claims that it worked without touching dopaminethe brain's 'reward / worth-chasing' chemical; drives motivation and focus, or through some unique mechanism, did not really hold up; the practical picture is a weak dopaminergic stimulant ^[5].

What set pemoline apart clinically was its slow, gentle onset. Where methylphenidate and amphetamine act within an hour, pemoline builds up over days to weeks, giving a smoother, longer-acting effect from a single morning dose ^[5]. That was attractive for once-daily school dosing, but it also made it feel less reliable, and it consistently came out as a 'second-line' stimulant behind methylphenidate and amphetamine in comparative work ^[5]. In narcolepsy the same profile showed up: pemoline was somewhat less effective than methylphenidate at keeping people awake, though it could improve certain performance measures ^[11][12][13].

It does work for ADHD, and efficacy was never really the problem. Controlled crossover trials found it clearly better than placebo in children ^[3], adolescents ^[2], and adults ^[1], with responder rates in the rough range of 50 to 60 percent, and a randomized trial even showed benefit in substance-abusing adolescents with ADHD ^[4]. In narcolepsy the objective sleep-lab data were more lukewarm, improving performance more than raw wakefulness ^[11].

The problem was the liver, and it is the defining fact about this drug. Pemoline can cause hepatotoxicity ranging from harmless enzyme bumps to fulminant, fatal liver failure, and the injury is idiosyncratic: it can appear late in treatment and keep progressing even after the drug is stopped ^[8]. One analysis estimated that a child on pemoline had roughly a 45-fold increased risk of acute liver failure versus the background rate ^[7]; several cases went to liver transplant and some were fatal ^[8][9]. A later surveillance review noted the safety signal was statistically detectable as early as 1978, yet the drug stayed on the US market until it was finally withdrawn about 30 years after launch, in the mid-2000s, and was pulled in Canada and much of Europe as well ^[10]. Because of this, guidelines had already demoted it to a last-line agent requiring frequent liver-enzyme monitoring long before it was withdrawn ^[14][15].