Pemoline (4-keto-aminorex, 'Cylert') is an interesting one. It is a fabulous looking molecule--a derivative of the much ballyhooed stimulant hit of 1986, 4-methylaminorex (4-MAX)--and is the most researched phenyloxazolidine. This compound was introduced as a treatment for ADHD in children that lasted 12-14 hours (much longer than methylphenidate), but is no longer widely used due to fear of liver toxicity, a risk with all of the phenyloxazolidine compounds that appears to be most severe with pemoline. The risk is still relatively low, but has given pemoline a bad reputation. Virtually no doctors will prescribe this compound, as it has a black box (fatal warning) in the PDR and requires a patient consent form to prescribe. If you get a script, be sure to request a dosage level that will actually do something for an adult. The average child dose was 37.5 mg qD, but a study of Royal AF pilots in the UK revealed 112.5-150 mg of pemoline magnesium to be the optimum dose for cognitive enhancement in the wake of severe fatigue.
As for mechanism of action, some researchers think that the phenyloxazolidines act mainly as reuptake inhibitors at the DAT and substrates at the SERT--they inhibit the reuptake of dopamine, but cause the release of serotonin. One prominent study, however, demonstrated that aminorex and related compounds act as substrates for both the DAT and SERT proteins, rendering them similar to d-methamphetamine in terms of neurotoxicity and cardiac side effects (Zheng et al, 1997, J. Pharm. Pharmacol. 49: 89-96). Another study revealed long-term decreases in tryptophan hydroxylase levels after administration of 4-methylaminorex (a possible sign of serotonergic neruotoxicity, but kind of weak, argument wise), but no signs of dopaminergic toxicity were seen (Hanson et al, 1992, Eur. J. Pharmacol. 218:287-293).