The absorption rate of zaleplon is rapid and the onset of therapeutic effects is typically breached within 5–15 minutes following ingestion. Zaleplon should be understood as an ultrashort-acting sedative-hypnotic drug for the treatment of insomnia. Zaleplon increases EEG power density in the δ-frequency band and a decrease in the energy of the θ-frequency band

Pharmacokinetics
Zaleplon is primarily metabolised by aldehyde oxidase, and its half-life can be affected by substances which inhibit or induce aldehyde oxidase. Taken orally, zaleplon reaches full concentration in about one hour. It is extensively metabolised into 5-oxozaleplon and 5-oxodesethylzaleplon (the latter via desethylzaleplon), with less than 1% of it excreted intact in urine. Chemistry
Pure zaleplon in its solid state is a white to off-white powder with very low solubility in water, as well as low solubility in ethanol and propylene glycol. It has a constant octanol-water partition coefficient of log P = 1.23 in the pH range between 1 and 7. It is classified as a pyrazolopyrimidine. Synthesis
The synthesis starts with the condensation of 3-acetylacetanilide (1) with N,N-dimethylformamide dimethyl acetal (DMFDMA) to give the eneamide (2). The anilide nitrogen is then alkylated by means of sodium hydride and ethyl iodide to give 3. The first step in the condensation with 3-amino-4-cyanopyrazole can be visualized as involving an addition-elimination reaction sequence on the eneamide function to give a transient intermediate such as 5. Cyclization then leads to formation of the fused pyrimidine ring to afford zaleplon (6).
It is taken alone, or in combination with complementary agents such as phenytoin, in commercial animal euthanasia injectable solutions. In the Netherlands, it is part of the standard protocol for physician-assisted suicide for self-administration by the patient.It is taken by mouth for physician-assisted death in the United States states of Oregon, Washington, Vermont, and California (as of January, 2016).The oral dosage of pentobarbital indicated for physician-assisted suicide in Oregon is typically 10 g of liquid.In Switzerland, sodium pentobarbital is administered to the patient intravenously. Once administered, sleep is induced within 30 seconds, and the heart stops beating within 3 minutes. Execution
Pentobarbital has been used or considered as a substitute for other drugs previously used for capital punishment in the United States when those drugs are unavailable. Such use however is illegal under Danish law, and when this was discovered, after public outcry in Danish media, Lundbeck, the owner of the drug, stopped selling it to US states that impose the death penalty. US distributors of the drug are forbidden by the owner to sell it to any customers, such as state authorities, that practice or participate in executions of humans.Texas began using pentobarbital for executing death-row inmates by lethal injection on July 18, 2012.