Table 1.

Pharmacokinetic parameters for eszopiclone in healthy adults and populations at risk

Non-elderly subjects(1)

rapidly absorbed (data not available for eszopiclone; racemic zopiclone: 95% of absorption with a bioavailability of 80%).

Cmax(2): 87.3 ng/mL

Tmax(3): 1.0–1.6 hours

AUC(4): 691.3 mg/mL

weakly bound to plasma protein (52%–59%)

t½(5): 6.0 hours

Vd(6): 98.6 L

effect of high-fat meal: reduces Cmax by 21%, and delays Tmax by approximately 1 hour; t½ remains unchanged.

metabolized by oxidation and demethylation to (S)-zopiclone-N-oxide and (S)-N- desmethyl zopiclone. CYP3A4 and CYP2E1 enzymes are involved in the metabolism of eszopiclone.

excreted in the urine primarily as metabolites; less than 10% of the orally administered eszopiclone is excreted as parent drug.

Elderly subjects

the metabolism is reduced resulting in increased AUC (41%) and prolonged t½ to approximately 9 hours.

Hepatic impairment

the AUC was increased 2-fold in patients with severe impairment (alcoholic cirrhosis); Cmax and Tmax remained unchanged.

Renal impairment

reductions in clearance in patients with mild, moderate, or severe renal impairment were not significant.

Women who are breast-feeding

eszopiclone is secreted into breast milk.

Distribution to salivary glands

the data on eszopiclone distribution to salivary glands are not complete. Following racemic zopiclone administration bitter taste occurs when saliva concentrations exceed 50 μg/L.

From Fernández et al (1993, ¹⁹⁹⁵⁾; Noble et al (1998); Lunesta [Prescribing information] 2005.

⁽¹⁾Single doses of up to 7.5 mg and once-daily administration of 1.0, 3.0, and 6.0 mg for 7 days.

⁽²⁾C_max: maximum plasma concentration.

⁽³⁾T_max: time to peak concentration.

⁽⁴⁾AUC: area under the concentration curve.

⁽⁵⁾t_½: mean elimination half-life.

⁽⁶⁾V_d: volume of distribution.