| Indication |
For the treatment of short-term treatment of insomnia in adults. |
| Pharmacodynamics |
Zaleplon is a nonbenzodiazepine hypnotic from the
pyrazolopyrimidine class and is indicated for the short-term treatment
of insomnia. While Zaleplon is a hypnotic agent with a chemical
structure unrelated to benzodiazepines, barbiturates, or other drugs
with known hypnotic properties, it interacts with the gamma-aminobutyric
acid-benzodiazepine (GABABZ) receptor complex. Subunit modulation of the GABABZ
receptor chloride channel macromolecular complex is hypothesized to be
responsible for some of the pharmacological properties of
benzodiazepines, which include sedative, anxiolytic, muscle relaxant,
and anticonvulsive effects in animal models. Zaleplon also binds
selectively to the CNS GABAA-receptor chloride ionophore complex at benzodiazepine(BZ) omega-1 (BZ1, ο1) receptors. |
| Mechanism of action |
Zaleplon exerts its action through subunit modulation of the GABABZ
receptor chloride channel macromolecular complex. Zaleplon also binds
selectively to the brain omega-1 receptor located on the alpha subunit
of the GABA-A/chloride ion channel receptor complex and potentiates
t-butyl-bicyclophosphorothionate (TBPS) binding. |
| Absorption |
Absorption Zaleplon is rapidly and almost completely absorbed following oral administration. |
| Volume of distribution |
|
| Protein binding |
Approximately 60% (in vitro plasma protein binding). |
| Metabolism |
Zaleplon is primarily metabolized by aldehyde oxidase. |
| Route of elimination |
Zaleplon is metabolized primarily by the liver and undergoes
significant presystemic metabolism. After oral administration, zaleplon
is extensively metabolized, with less than 1% of the dose excreted
unchanged in urine. Renal excretion of unchanged zaleplon accounts for
less than 1% of the administered dose. |
| Half life |
Approximately 1 hour |
| Clearance |
|
| Toxicity |
Side effects include abdominal pain, amnesia, dizziness,
drowsiness, eye pain, headache, memory loss, menstrual pain, nausea,
sleepiness, tingling, weakness |
