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USAGE OF RAMELTEON ROZEREM
Ramelteon Rozerem is an MT1/MT2 receptor agonist being
studied for the treatment of sleeplessness and circadian
rhythm sleep disorders. Ramelteon Rozerem shows full agonist
activity in vitro in cells expressing human MT1 or MT2
receptors, and high selectivity for human MT1 and MT2
receptors compared to the MT3 receptor. The activity of
Ramelteon Rozerem at the MT1 and MT2 receptors is believed
to contribute to its sleep-promoting properties, as these
receptors, acted upon by endogenous melatonin, are thought
to be involved in the maintenance of the circadian rhythm
underlying the normal sleep-wake cycle.
The major metabolite of Ramelteon Rozerem, M-II, is active
and has approximately 1/10 and 1/5 binding affinity of the
parent molecule for the human MT1 and MT2 receptors,
respectively, and is 17 – 25-fold less potent than ramelteon
in vitro functional assays. Although the potency of M-II at
MT1 and MT2 receptors is lower than the parent drug, M-II
circulates at higher concentrations than the parent
producing 20 – 100-fold better mean systemic exposure when
compared to Ramelteon Rozerem.
EFFECTS OF RAMELTEON ROZEREM
Ramelteon Rozerem is absorbed quickly, with median peak
concentrations occurring at approximately 0.75 hour (range,
0.5 to 1.5 hours) after fasted oral administration. Although
the total absorption of Ramelteon Rozerem is at least 84%,
the absolute oral bioavailability is only 1.8% due to
extensive first-pass metabolism.
DOSAGE OF RAMELTEON ROZEREM
Ramelteon Rozerem is being marketed by Takeda
Pharmaceuticals America, Incorporation. Daily one 8 mg dose
of Ramelteon Rozerem should be taken before half an hour of
going to bed.
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