Article: Zaleplon

Zaleplon
Systematic (IUPAC) name
N-[3-(7-cyano-1,5,9-triazabicyclo[4.3.0]nona- 2,4,6,8-tetraen-2-yl)phenyl]-N-ethyl-acetamide
Identifiers
CAS number	151319-34-5
ATC code	N05CF03
PubChem	5719
DrugBank	APRD00411
Chemical data
Formula	C17H15N5O
Mol. weight	305.34
Pharmacokinetic data
Bioavailability	30% (oral)
Metabolism	Hepatic
Half life	1 hour
Excretion	Renal
Therapeutic considerations
Pregnancy cat.	C (USA)
Legal status	Schedule IV (US)
Routes	Oral

Zaleplon (marketed under the brand names Sonata® and Starnoc®) is a sedative/hypnotic, mainly used for insomnia. It is a nonbenzodiazepine hypnotic from the pyrazolopyrimidine class.

Chemistry

Zaleplon is a white to off-white powder that has very low solubility in water as well as low solubility in alcohol and propylene glycol. It has a partition coefficient in octanol/water is constant (log PC = 1.23) when the pH range is between 1 and 7.

Mode of action

Taken orally, Zaleplon reaches full concentration in approximately one hour. It is extensively metabolised, into 5-oxo-zaleplon and 5-oxo-desethylzaleplon (the latter via desethylzaleplon), with less than 1% of it excreted intact in urine.

Zaleplon interacts with the GABA receptor complex and shares some of the pharmacological properties of the benzodiazepines. Although not a benzodiazepine, Zaleplon can cause similar effects: anterograde amnesia (forgetting the period during the effects) as the most common.

Zaleplon is primarily metabolised by aldehyde oxidase, and its half-life can be affected by substances which inhibit or induce aldehyde oxidase.

Side-effects

Zaleplon may cause hallucinations, abnormal behavior, severe confusion, day-time drowsiness, dizziness or lightheadedness, unsteadiness and/or falls, double vision or other vision problems, agitation, headache, nausea, vomiting, diarrhea or abdominal pain, depression, muscle weakness, tremor, vivid or abnormal dreams and memory difficulties or amnesia.

Zaleplon is habit-forming, meaning addiction may occur. Stopping this medication suddenly after prolonged or frequent use may cause withdrawal effects such as mood changes, anxiety, and restlessness.