Information for Patients
Physicians are advised to discuss the following issues with
patients for whom they prescribe citalopram.
Patients should be cautioned about the risk of serotonin syndrome with the
concomitant use of citalopram and triptans, tramadol or other serotonergic
agents.
Although in controlled studies citalopram has not been shown to impair
psychomotor performance, any psychoactive drug may impair judgment, thinking, or
motor skills, so patients should be cautioned about operating hazardous
machinery, including automobiles, until they are reasonably certain that
citalopram therapy does not affect their ability to engage in such
activities.
Patients should be told that, although citalopram has not been shown in
experiments with normal subjects to increase the mental and motor skill
impairments caused by alcohol, the concomitant use of citalopram and alcohol in
depressed patients is not advised.
Patients should be advised to inform their physician if they are taking, or
plan to take, any prescription or over-the-counter drugs, as there is a
potential for interactions.
Patients should be cautioned about the concomitant use of citalopram and
NSAIDs, aspirin, warfarin, or other drugs that affect coagulation since the
combined use of psychotropic drugs that interfere with serotonin reuptake and
these agents has been associated with an increased risk of bleeding.
Patients should be advised to notify their physician if they become pregnant
or intend to become pregnant during therapy.
Patients should be advised to notify their physician if they are
breastfeeding an infant.
While patients may notice improvement with citalopram therapy in 1 to 4
weeks, they should be advised to continue therapy as directed.
Prescribers or other health professionals should inform patients, their
families, and their caregivers about the benefits and risks associated with
treatment with citalopram and should counsel them in its appropriate use. A
patient Medication Guide about "Antidepressant Medicines, Depression and other
Serious Mental Illness, and Suicidal Thoughts or Actions" is available for
citalopram. The prescriber or health professional should instruct patients,
their families, and their caregivers to read the Medication Guide and should
assist them in understanding its contents. Patients should be given the
opportunity to discuss the contents of the Medication Guide and to obtain
answers to any questions they may have. The complete text of the Medication
Guide is reprinted at the end of this document.
Patients should be advised of the following issues and asked to alert their
prescriber if these occur while taking citalopram.
Clinical Worsening and Suicide Risk: Patients, their
families, and their caregivers should be encouraged to be alert to the emergence
of anxiety, agitation, panic attacks, insomnia, irritability, hostility,
aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania,
mania, other unusual changes in behavior, worsening of depression, and suicidal
ideation, especially early during antidepressant treatment and when the dose is
adjusted up or down. Families and caregivers of patients should be advised to
look for the emergence of such symptoms on a day-to-day basis, since changes may
be abrupt. Such symptoms should be reported to the patient’s prescriber or
health professional, especially if they are severe, abrupt in onset, or were not
part of the patient’s presenting symptoms. Symptoms such as these may be
associated with an increased risk for suicidal thinking and behavior and
indicate a need for very close monitoring and possibly changes in the
medication.
Laboratory Tests
There are no specific laboratory tests recommended.
Drug Interactions
Serotonergic Drugs: Based on the
mechanism of action of SNRIs and SSRIs including citalopram, and the potential
for serotonin syndrome, caution is advised when citalopram is coadministered
with other drugs that may affect the serotonergic neurotransmitter systems, such
as triptans, linezolid (an antibiotic which is a reversible non-selective MAOI),
lithium, tramadol, or St. John’s Wort (see WARNINGS-Serotonin Syndrome). The concomitant use of
citalopram with other SSRIs, SNRIs or tryptophan is not
recommended (see PRECAUTIONS - Drug
Interactions).
Triptans: There have been rare postmarketing reports
of serotonin syndrome with use of an SSRI and a triptan. If concomitant
treatment of citalopram with a triptan is clinically warranted, careful
observation of the patient is advised, particularly during treatment initiation
and dose increases (see WARNINGS - Serotonin
Syndrome).
CNS Drugs - Given the primary CNS effects of citalopram, caution should be
used when it is taken in combination with other centrally acting drugs.
Alcohol - Although citalopram did not potentiate the cognitive and motor
effects of alcohol in a clinical trial, as with other psychotropic medications,
the use of alcohol by depressed patients taking citalopram is not
recommended.
Monoamine Oxidase Inhibitors (MAOIs) - See CONTRAINDICATIONS and WARNINGS.
Drugs That Interfere With Hemostasis (NSAIDs, Aspirin, Warfarin, etc.)-
Serotonin release by platelets plays an important role in hemostasis.
Epidemiological studies of the case-control and cohort design that have
demonstrated an association between use of psychotropic drugs that interfere
with serotonin reuptake and the occurrence of upper gastrointestinal bleeding
have also shown that concurrent use of an NSAID or aspirin may potentiate the
risk of bleeding. Altered anticoagulant effects, including increased bleeding,
have been reported when SSRIs and SNRIs are coadministered with warfarin.
Patients receiving warfarin therapy should be carefully monitored when
citalopram is initiated or discontinued.
Cimetidine - In subjects who had received 21 days of 40 mg/day citalopram,
combined administration of 400 mg/day cimetidine for 8 days resulted in an
increase in citalopram AUC and Cmax of 43% and 39%,
respectively. The clinical significance of these findings is unknown.
Digoxin - In subjects who had received 21 days of 40 mg/day citalopram,
combined administration of citalopram and digoxin (single dose of 1 mg) did not
significantly affect the pharmacokinetics of either citalopram or digoxin.
Lithium - Coadministration of citalopram (40 mg/day for 10 days) and lithium
(30 mmol/day for 5 days) had no significant effect on the pharmacokinetics of
citalopram or lithium. Nevertheless, plasma lithium levels should be monitored
with appropriate adjustment to the lithium dose in accordance with standard
clinical practice. Because lithium may enhance the serotonergic effects of
citalopram, caution should be exercised when citalopram and lithium are
coadministered.
Pimozide - In a controlled study, a single dose of pimozide 2 mg
co-administered with citalopram 40 mg given once daily for 11 days was
associated with a mean increase in QTc values of approximately 10 msec compared
to pimozide given alone. Citalopram did not alter the mean AUC or Cmax of pimozide. The mechanism of this pharmacodynamic
interaction is not known.
Theophylline - Combined administration of citalopram (40 mg/day for 21 days)
and the CYP1A2 substrate theophylline (single dose of 300 mg) did not affect the
pharmacokinetics of theophylline. The effect of theophylline on the
pharmacokinetics of citalopram was not evaluated.
Sumatriptan - There have been rare postmarketing reports describing patients
with weakness, hyperreflexia, and incoordination following the use of a SSRI and
sumatriptan. If concomitant treatment with sumatriptan and an SSRI (e.g.,
fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram) is clinically
warranted, appropriate observation of the patient is advised.
Warfarin - Administration of 40 mg/day citalopram for 21 days did not affect
the pharmacokinetics of warfarin, a CYP3A4 substrate. Prothrombin time was
increased by 5%, the clinical significance of which is unknown.
Carbamazepine - Combined administration of citalopram (40 mg/day for 14 days)
and carbamazepine (titrated to 400 mg/day for 35 days) did not significantly
affect the pharmacokinetics of carbamazepine, a CYP3A4 substrate. Although
trough citalopram plasma levels were unaffected, given the enzyme-inducing
properties of carbamazepine, the possibility that carbamazepine might increase
the clearance of citalopram should be considered if the two drugs are
coadministered.
Triazolam - Combined administration of citalopram (titrated to 40 mg/day for
28 days) and the CYP3A4 substrate triazolam (single dose of 0.25 mg) did not
significantly affect the pharmacokinetics of either citalopram or triazolam.
Ketoconazole - Combined administration of citalopram (40 mg) and ketoconazole
(200 mg) decreased the Cmax and AUC of ketoconazole by
21% and 10%, respectively, and did not significantly affect the pharmacokinetics
of citalopram.
CYP3A4 and 2C19 Inhibitors - In vitro studies
indicated that CYP3A4 and 2C19 are the primary enzymes involved in the
metabolism of citalopram. However, coadministration of citalopram (40 mg) and
ketoconazole (200 mg), a potent inhibitor of CYP3A4, did not significantly
affect the pharmacokinetics of citalopram. Because citalopram is metabolized by
multiple enzyme systems, inhibition of a single enzyme may not appreciably
decrease citalopram clearance.
Metoprolol - Administration of 40 mg/day citalopram for 22 days resulted in a
two-fold increase in the plasma levels of the betaadrenergic blocker metoprolol.
Increased metoprolol plasma levels have been associated with decreased
cardioselectivity. Coadministration of citalopram and metoprolol had no
clinically significant effects on blood pressure or heart rate.
Imipramine and Other Tricyclic Antidepressants (TCAs) - In vitro studies suggest that citalopram is a relatively
weak inhibitor of CYP2D6. Coadministration of citalopram (40 mg/day for 10 days)
with the TCA imipramine (single dose of 100 mg), a substrate for CYP2D6, did not
significantly affect the plasma concentrations of imipramine or citalopram.
However, the concentration of the imipramine metabolite desipramine was
increased by approximately 50%. The clinical significance of the desipramine
change is unknown. Nevertheless, caution is indicated in the coadministration of
TCAs with citalopram.
Electroconvulsive Therapy (ECT) - There are no clinical studies of the
combined use of electroconvulsive therapy (ECT) and citalopram.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenesis
Citalopram was administered in the diet to NMRI/BOM strain mice and COBS WI
strain rats for 18 and 24 months, respectively. There was no evidence for
carcinogenicity of citalopram in mice receiving up to 240 mg/kg/day, which is
equivalent to 20 times the maximum recommended human daily dose (MRHD) of 60 mg
on a surface area (mg/m2) basis. There was an increased
incidence of small intestine carcinoma in rats receiving 8 or 24 mg/kg/day,
doses which are approximately 1.3 and 4 times the MRHD, respectively, on a
mg/m2 basis. A no-effect dose for this finding was not
established. The relevance of these findings to humans is unknown.
Mutagenesis
Citalopram was mutagenic in the in vitro bacterial
reverse mutation assay (Ames test) in 2 of 5 bacterial strains (Salmonella TA98
and TA1537) in the absence of metabolic activation. It was clastogenic in the
in vitro Chinese hamster lung cell assay for
chromosomal aberrations in the presence and absence of metabolic activation.
Citalopram was not mutagenic in the in vitro
mammalian forward gene mutation assay (HPRT) in mouse lymphoma cells or
in a coupled in vitro/in vivo unscheduled DNA
synthesis (UDS) assay in rat liver. It was not clastogenic in the in vitro chromosomal aberration assay in human lymphocytes
or in two in vivo mouse micronucleus assays.
Impairment of Fertility
When citalopram was administered orally to 16 male and 24 female rats prior
to and throughout mating and gestation at doses of 32, 48, and 72 mg/kg/day,
mating was decreased at all doses, and fertility was decreased at doses ≥ 32
mg/kg/day, approximately 5 times the MRHD of 60 mg/day on a body surface area
(mg/m2) basis. Gestation duration was increased at 48
mg/kg/day, approximately 8 times the MRHD.
Pregnancy
Pregnancy Category C
In animal reproduction studies, citalopram has been shown to have adverse
effects on embryo/fetal and postnatal development, including teratogenic
effects, when administered at doses greater than human therapeutic doses.
In two rat embryo/fetal development studies, oral administration of
citalopram (32, 56, or 112 mg/kg/day) to pregnant animals during the period of
organogenesis resulted in decreased embryo/fetal growth and survival and an
increased incidence of fetal abnormalities (including cardiovascular and
skeletal defects) at the high dose, which is approximately 18 times the MRHD of
60 mg/day on a body surface area (mg/m2) basis. This dose
was also associated with maternal toxicity (clinical signs, decreased body
weight gain). The developmental, no-effect dose of 56 mg/kg/day is approximately
9 times the MRHD on a mg/m2 basis. In a rabbit study, no
adverse effects on embryo/fetal development were observed at doses of up to 16
mg/kg/day, or approximately 5 times the MRHD on a mg/m2
basis. Thus, teratogenic effects were observed at a maternally toxic dose in the
rat and were not observed in the rabbit.
When female rats were treated with citalopram (4.8, 12.8, or 32 mg/kg/day)
from late gestation through weaning, increased offspring mortality during the
first 4 days after birth and persistent offspring growth retardation were
observed at the highest dose, which is approximately 5 times the MRHD on a
mg/m2 basis. The no-effect dose of 12.8 mg/kg/day is
approximately 2 times the MRHD on a mg/m2 basis. Similar
effects on offspring mortality and growth were seen when dams were treated
throughout gestation and early lactation at doses ≥ 24 mg/kg/day, approximately
4 times the MRHD on a mg/m2 basis. A no-effect dose was
not determined in that study.
There are no adequate and well-controlled studies in pregnant women;
therefore, citalopram should be used during pregnancy only if the potential
benefit justifies the potential risk to the fetus.
Pregnancy-Nonteratogenic Effects
Neonates exposed to citalopram and other SSRIs or SNRIs,
late in the third trimester, have developed complications requiring prolonged
hospitalization, respiratory support, and tube feeding. Such complications can
arise immediately upon delivery. Reported clinical findings have included
respiratory distress, cyanosis, apnea, seizures, temperature instability,
feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia,
hyperreflexia, tremor, jitteriness, irritability, and constant crying. These
features are consistent with either a direct toxic effect of SSRIs and SNRIs or,
possibly, a drug discontinuation syndrome. It should be noted that, in some
cases, the clinical picture is consistent with serotonin syndrome (see WARNINGS).
Infants exposed to SSRIs in late pregnancy may have an increased risk for
persistent pulmonary hypertension of the newborn (PPHN). PPHN occurs in 1-2 per
1000 live births in the general population and is associated with substantial
neonatal morbidity and mortality. In a retrospective, case-control study of 377
women whose infants were born with PPHN and 836 women whose infants were born
healthy, the risk for developing PPHN was approximately six-fold higher for
infants exposed to SSRIs after the 20th week of gestation compared to infants
who had not been exposed to antidepressants during pregnancy. There is currently
no corroborative evidence regarding the risk for PPHN following exposure to
SSRIs in pregnancy; this is the first study that has investigated the potential
risk. The study did not include enough cases with exposure to individual SSRIs
to determine if all SSRIs posed similar levels of PPHN risk.
When treating a pregnant woman with citalopram during the third trimester,
the physician should carefully consider both the potential risks and benefits of
treatment (see DOSAGE AND ADMINISTRATION).
Physicians should note that in a prospective longitudinal study of 201
women with a history of major depression who were euthymic at the beginning of
pregnancy, women who discontinued antidepressant medication during pregnancy
were more likely to experience a relapse of major depression than women who
continued antidepressant medication.
Labor and Delivery
The effect of citalopram on labor and delivery in humans is
unknown.
Nursing Mothers
As has been found to occur with many other drugs,
citalopram is excreted in human breast milk. There have been two reports of
infants experiencing excessive somnolence, decreased feeding, and weight loss in
association with breastfeeding from a citalopram-treated mother; in one case,
the infant was reported to recover completely upon discontinuation of citalopram
by its mother and in the second case, no follow-up information was available.
The decision whether to continue or discontinue either nursing or citalopram
therapy should take into account the risks of citalopram exposure for the infant
and the benefits of citalopram treatment for the mother.
Pediatric Use
Safety and effectiveness in the pediatric population have
not been established (see BOX WARNING and
WARNINGS—Clinical Worsening and Suicide Risk). Two
placebo-controlled trials in 407 pediatric patients with MDD have been conducted
with citalopram, and the data were not sufficient to support a claim for use in
pediatric patients. Anyone considering the use of citalopram in a child or
adolescent must balance the potential risks with the clinical need.
Geriatric Use
Of 4422 patients in clinical studies of citalopram, 1357
were 60 and over, 1034 were 65 and over, and 457 were 75 and over. No overall
differences in safety or effectiveness were observed between these subjects and
younger subjects, and other reported clinical experience has not identified
differences in responses between the elderly and younger patients, but greater
sensitivity of some older individuals cannot be ruled out. Most elderly patients
treated with citalopram in clinical trials received daily doses between 20 and
40 mg (see DOSAGE AND
ADMINISTRATION).
SSRIs and SNRIs, including citalopram, have been associated with cases of
clinically significant hyponatremia in elderly patients, who may be at greater
risk for this adverse event (see PRECAUTIONS,
Hyponatremia).
In two pharmacokinetic studies, citalopram AUC was increased by 23% and 30%,
respectively, in elderly subjects as compared to younger subjects, and its
half-life was increased by 30% and 50%, respectively (see CLINICAL PHARMACOLOGY).
20 mg/day is the recommended dose for most elderly patients (see DOSAGE AND ADMINISTRATION).