Almotriptan (LAS 31416) is a new, oral, specific 5-hydroxytryptamine(1B/1D) receptor agonist for the treatment of migraine. The pharmacokinetics and safety of a range of oral doses were assessed in 23 healthy male volunteers. Peak plasma concentrations were reached between 1.5 and 4 h after dosing. The maximum plasma concentration and area under the curve showed dose proportionality over the dose range 5-200 mg. The elimination half-life was constant at approximately 3 h across all dose levels. A substantial proportion of the initial dose was excreted in urine (27%-39%) during 12 h post-dose and the main excretory product was unchanged drug. Three major urinary metabolites were detected, all of which were pharmacologically inactive. The most common events following almotriptan administration were headache, tiredness and mild nausea. Nine events (18%) were classed as probably related to almotriptan and these were all at the highest dose level of 200 mg. The maximum tolerated dose of almotriptan was, therefore, determined as 150 mg. In conclusion, almotriptan is well tolerated following single, oral doses up to 150 mg and has predictable pharmacokinetics.