74 Section 2/ Drugs Acting on CNSIt is indicated in typical and atypical
absence seizure, infantile spasms, myoclonic
epilepsy, atonic seizures, minor motor sei-
zures of childhood, refractory grandmal
epilepsy or temporal lobe epilepsy and sei-
zures not controlled by conventional
antiepileptics.
NEWER COMPOUNDSZOPICLONE
It is a novel hypnotic belonging to
cyclopyrrolone derivative. It is useful in short
term management of insomnia and has low
abuse potential.
Zopiclone exhibits anticonvulsant,
muscle relaxant and hypnosedative proper-
ties similar to benzodiazepines.
Zopiclone is rapidly absorbed after oral
dosing. Its elimination half-life period is 3.5-
6 hours. It is mainly excreted in urine.
Adverse effects include metallic or bit-
ter after-taste, nausea, vomiting, allergic skin
reaction, irritability, hallucinations, depres-
sion, amnesia and confusion.
It is indicated in treatment of transient,
situational and chronic insomnia, insomnia
secondary to psychiatric disorders.
ZOLPIDEM
Zolpidem is a non-benzodiazepine hyp-
notic of the imidazopyridine class. It is a
GABAA receptor agonist selective for
omega-1 receptor subunit.
Zolpidem is rapidly absorbed and has a
quick onset of hypnotic action. Bio-
availability is 70 percent following oral
administration and the drug demonstrates
linear kinetics in the therapeutic dose range.
Peak plasma concentration is reached at 0.5
and 3 hours. The elimination half-life is
short. It is 92% plasma protein bound and is
metabolised in liver to inactive metabolites.
It is eliminated in the urine and in the faeces.
Adverse effects include diarrhoea, nau-
sea, vomiting, vertigo, dizziness, headache,
drowsiness, nightmares, asthenia, memory
disturbances, depression, confusion, diplo-
pia, tremor and ataxia.
It is indicated in short term management
of insomnia.ZALEPLON
It is a nonbenzodiazepine hypnotic.
Zaleplon interacts and binds selectively to the
brain omega-1 receptor situated on the alpha
subunit of the GABAA receptor complex.
It is rapidly and almost completely
absorbed following oral administration. It
undergoes significant presystemic metabo-
lism, all the metabolites are pharmacologi-
cally inactive.
Adverse effects include dizziness, am-
nesia, headache, tremor, nausea, abdominal
pain, dyspepsia, anorexia, eye pain, asthe-
nia, malaise and myalgia.
It is indicated in short term management
of insomnia.