Table 15.2 (continued)
Antidepressant
Clinical study
Clinical observations
Escitalopram
Rao (2007)
Adolescents, elderly individuals, and patients with
hepatic impairment do not have clinically relevant
differences in PK compared with healthy young adults,
implying that adjustment of escitalopram dosage is not
necessary in these patient groups. Escitalopram is
metabolized by CYP isoenzymes like CYP2C19,
CYP2D6, and CYP3A4. However, ritonavir, a potent
inhibitor of CYP3A4, does not affect the PK values of
escitalopram
Chung et al. (2017)
The (S)-enantiomer of citalopram has a potential QT
prolonging effect. In a clinical study, 12 healthy elderly
individuals received a single oral dose of escitalopram
(20 mg), and their pharmacokinetics and QT effect data
were compared with data from 33 younger adults
obtained in a previous study. Serial blood samples for
PK analysis were collected and ECG was performed up
to 48 h post-dose. The elderly and younger adults
showed similar PK profiles. The mean baseline-
adjusted QT (dQT) time profiles were similar and the
mean values of maximum dQT were not significantly
different between the elderly and the younger adults
Venlafaxine
Hansen et al.
(2017)
The median dose-corrected serum level for venlafaxine
was 1.49 nmol/L/mg, while the dose-corrected serum
level of men and women were 1.21 nmol/L/mg and
1.60 nmol/L/mg, respectively, after a median daily dose
of 225 mg. The dose-corrected sum of venlafaxine and
o-desmethyl-venlafaxine (ODV) was 8.91 nmol/L/mg
versus 5.52 nmol/L/mg for patients above 64 years and
below the age of 65 years, respectively. Dose-corrected
plasma concentrations of venlafaxine and ODV are
increased to a clinically significant degree in patients
above the age of 64, and initiation of venlafaxine
therapy in the elderly should be made cautiously and
supported by drug measurements
Allard et al. (2004)
Benefits of venlafaxine treatment in elderly patients
with major depression were similar to those observed in
younger adults as were reported adverse events or side
effects
Hefner et al. (2019)
In elderly inpatients aged 65 years, amitriptyline and
venlafaxine induce significant QT prolongation
depending on drug concentrations in blood
Duloxetine
Knadler et al.
(2011)
Duloxetine achieves a maximum plasma concentration
(Cmax) of approx. 47 ng/mL (40 mg twice-daily dosing)
to 110 ng/mL (80 mg twice-daily dosing) around 6 h
after dosing. The elimination half-life of duloxetine is
approximately 10–12 h and the volume of distribution
is about 1640 ng/L. Patient demographic characteristics
found to influence the PK of duloxetine include gender,
smoking status, age, ethnicity, CYP450 2D6 genotype,
hepatic function, and renal function. Of these, only
(continued)
15
The Importance of Drug Dose Adjustment in Elderly Patients with Special. . .
255