Escitalopram Oxalate

1 INDICATIONS AND USAGE Escitalopram oxalate is a selective serotonin reuptake inhibitor (SSRI) indicated for: Acute and Maintenance Treatment of Major Depressive Disorder (MDD) in adults and adolescents aged 12 to 17 years (1.1) Acute Treatment of Generalized Anxiety Disorder (GAD) in adults (1.2) 1.1 Major Depressive Disorder Escitalopram tablets are indicated for the acute and maintenance treatment of major depressive disorder in adults and in adolescents 12 to 17 years of age [see Clinical Studies (14.1) ] . A major depressive episode (DSM-IV) implies a prominent and relatively persistent (nearly every day for at least 2 weeks) depressed or dysphoric mood that usually interferes with daily functioning, and includes at least five of the following nine symptoms: depressed mood, loss of interest in usual activities, significant change in weight and/or appetite, insomnia or hypersomnia, psychomotor agitation or retardation, increased fatigue, feelings of guilt or worthlessness, slowed thinking or impaired concentration, a suicide attempt or suicidal ideation. 1.2 Generalized Anxiety Disorder Escitalopram tablets are indicated for the acute treatment of Generalized Anxiety Disorder (GAD) in adults [see Clinical Studies (14.2) ] . Generalized Anxiety Disorder (DSM-IV) is characterized by excessive anxiety and worry (apprehensive expectation) that is persistent for at least 6 months and which the person finds difficult to control. It must be associated with at least 3 of the following symptoms: restlessness or feeling keyed up or on edge, being easily fatigued, difficulty concentrating or mind going blank, irritability, muscle tension, and sleep disturbance.

2 DOSAGE AND ADMINISTRATION Escitalopram tablets should be administered once daily, in the morning or evening, with or without food. Escitalopram tablets should generally be administered once daily, morning or evening with or without food ( 2.1 , 2.2 ). Indication Recommended Dose MDD in Adolescents (2.1) Initial: 10 mg once daily Recommended: 10 mg once daily Maximum: 20 mg once daily MDD in Adults (2.1) Initial: 10 mg once daily Recommended: 10 mg once daily Maximum: 20 mg once daily GAD in Adults (2.2) Initial: 10 mg once daily Recommended: 10 mg once daily No additional benefits seen at 20 mg/day dose (2.1) . 10 mg/day is the recommended dose for most elderly patients and patients with hepatic impairment ( 2.3 ). No dosage adjustment for patients with mild or moderate renal impairment. Use caution in patients with severe renal impairment ( 2.3 ). Discontinuing Escitalopram Tablets: A gradual dose reduction is recommended ( 2.4 ). 2.1 Major Depressive Disorder Initial Treatment Adolescents The recommended dose of escitalopram tablets is 10 mg once daily. A flexible-dose trial of escitalopram tablets (10 to 20 mg/day) demonstrated the effectiveness of escitalopram tablets [see Clinical Studies (14.1) ] . If the dose is increased to 20 mg, this should occur after a minimum of three weeks. Adults The recommended dose of escitalopram tablets is 10 mg once daily. A fixed-dose trial of escitalopram tablets demonstrated the effectiveness of both 10 mg and 20 mg of escitalopram tablets, but failed to demonstrate a greater benefit of 20 mg over 10 mg [see Clinical Studies (14.1) ] . If the dose is increased to 20 mg, this should occur after a minimum of one week. Maintenance Treatment It is generally agreed that acute episodes of major depressive disorder require several months or longer of sustained pharmacological therapy beyond response to the acute episode. Systematic evaluation of continuing escitalopram tablets 10 or 20 mg/day in adults patients with major depressive disorder who responded while taking escitalopram tablets during an 8-week, acute-treatment phase demonstrated a benefit of such maintenance treatment [see Clinical Studies (14.1) ] . Nevertheless, the physician who elects to use escitalopram tablets for extended periods should periodically re-evaluate the long-term usefulness of the drug for the individual patient. Patients should be periodically reassessed to determine the need for maintenance treatment. 2.2 Generalized Anxiety Disorder Initial Treatment Adults The recommended starting dose of escitalopram tablets is 10 mg once daily. If the dose is increased to 20 mg, this should occur after a minimum of one week. Maintenance Treatment Generalized anxiety disorder is recognized as a chronic condition. The efficacy of escitalopram tablets in the treatment of GAD beyond 8 weeks has not been systematically studied. The physician who elects to use escitalopram tablets for extended periods should periodically re-evaluate the long-term usefulness of the drug for the individual patient. 2.3 Screen for Bipolar Disorder Prior to Starting Escitalopram Tablets Prior to initiating treatment with escitalopram tablets or another antidepressant, screen patients for a personal family history of bipolar disorder, mania, or hypomania [see Warnings and Precautions (5.5) ]. 2.4 Special Populations 10 mg/day is the recommended dose for most elderly patients and patients with hepatic impairment. No dosage adjustment is necessary for patients with mild or moderate renal impairment. Escitalopram tablets should be used with caution in patients with severe renal impairment. 2.5 Discontinuation of Treatment with Escitalopram Tablets Symptoms associated with discontinuation of escitalopram tablets and other SSRIs and SNRIs have been reported [see Warnings and Precautions (5.3) ] . Patients should be monitored for these symptoms when discontinuing treatment. A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the physician may continue decreasing the dose but at a more gradual rate. 2.6 Switching a Patient to or from a Monoamine Oxidase Inhibitor (MAOI) Intended to Treat Psychiatric Disorders At least 14 days should elapse between discontinuation of an MAOI intended to treat psychiatric disorders and initiation of therapy with escitalopram tablets. Conversely, at least 14 days should be allowed after stopping escitalopram tablets before starting an MAOI intended to treat psychiatric disorders [see Contraindications (4.1) ]. 2.7 Use of Escitalopram Tablets with Other MAOIs such as Linezolid or Methylene Blue Do not start escitalopram tablets in a patient who is being treated with linezolid or intravenous methylene blue because there is an increased risk of serotonin syndrome. In a patient who requires more urgent treatment of a psychiatric condition, other interventions, including hospitalization, should be considered [see Contraindications (4.1) ]. In some cases, a patient already receiving escitalopram tablets therapy may require urgent treatment with linezolid or intravenous methylene blue. If acceptable alternatives to linezolid or intravenous methylene blue treatment are not available and the potential benefits of linezolid or intravenous methylene blue treatment are judged to outweigh the risks of serotonin syndrome in a particular patient, escitalopram tablets should be stopped promptly, and linezolid or intravenous methylene blue can be administered. The patient should be monitored for symptoms of serotonin syndrome for 2 weeks or until 24 hours after the last dose of linezolid or intravenous methylene blue, whichever comes first. Therapy with escitalopram tablets may be resumed 24 hours after the last dose of linezolid or intravenous methylene blue [see Warnings and Precautions (5.2) ] . The risk of administering methylene blue by non-intravenous routes (such as oral tablets or by local injection) or in intravenous doses much lower than 1 mg/kg with escitalopram tablets is unclear. The clinician should, nevertheless, be aware of the possibility of emergent symptoms of serotonin syndrome with such use [see Warnings and Precautions (5.2) ] .

6 ADVERSE REACTIONS Most commonly observed adverse reactions (incidence ≥ 5% and at least twice the incidence of placebo patients) are: insomnia, ejaculation disorder (primarily ejaculatory delay), nausea, sweating increased, fatigue and somnolence, decreased libido, and anorgasmia (6.1) . To report SUSPECTED ADVERSE REACTIONS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. Clinical Trial Data Sources Pediatrics (6 to 17 years) Adverse events were collected in 576 pediatric patients (286 escitalopram oxalate, 290 placebo) with major depressive disorder in double-blind placebo-controlled studies. Safety and effectiveness of escitalopram oxalate in pediatric patients less than 12 years of age has not been established. Adults Adverse events information for escitalopram oxalate was collected from 715 patients with major depressive disorder who were exposed to escitalopram and from 592 patients who were exposed to placebo in double-blind, placebo-controlled trials. An additional 284 patients with major depressive disorder were newly exposed to escitalopram in open-label trials. The adverse event information for escitalopram oxalate in patients with GAD was collected from 429 patients exposed to escitalopram and from 427 patients exposed to placebo in double-blind, placebo-controlled trials. Adverse events during exposure were obtained primarily by general inquiry and recorded by clinical investigators using terminology of their own choosing. Consequently, it is not possible to provide a meaningful estimate of the proportion of individuals experiencing adverse events without first grouping similar types of events into a smaller number of standardized event categories. In the tables and tabulations that follow, standard World Health Organization (WHO) terminology has been used to classify reported adverse events. The stated frequencies of adverse reactions represent the proportion of individuals who experienced, at least once, a treatment emergent adverse event of the type listed. An event was considered treatment-emergent if it occurred for the first time or worsened while receiving therapy following baseline evaluation. Adverse Events Associated with Discontinuation of Treatment Major Depressive Disorder Pediatrics (6 to 17 years) Adverse events were associated with discontinuation of 3.5% of 286 patients receiving escitalopram oxalate and 1% of 290 patients receiving placebo. The most common adverse event (incidence at least 1% for escitalopram oxalate and greater than placebo) associated with discontinuation was insomnia (1% escitalopram oxalate, 0% placebo). Adults Among the 715 depressed patients who received escitalopram oxalate in placebo-controlled trials, 6% discontinued treatment due to an adverse event, as compared to 2% of 592 patients receiving placebo. In two fixed-dose studies, the rate of discontinuation for adverse events in patients receiving 10 mg/day escitalopram oxalate was not significantly different from the rate of discontinuation for adverse events in patients receiving placebo. The rate of discontinuation for adverse events in patients assigned to a fixed dose of 20 mg/day escitalopram oxalate was 10%, which was significantly different from the rate of discontinuation for adverse events in patients receiving 10 mg/day escitalopram oxalate (4%) and placebo (3%). Adverse events that were associated with the discontinuation of at least 1% of patients treated with escitalopram oxalate, and for which the rate was at least twice that of placebo, were nausea (2%) and ejaculation disorder (2% of male patients). Generalized Anxiety Disorder Adults Among the 429 GAD patients who received escitalopram oxalate 10 to 20 mg/day in placebo-controlled trials, 8% discontinued treatment due to an adverse event, as compared to 4% of 427 patients receiving placebo. Adverse events that were associated with the discontinuation of at least 1% of patients treated with escitalopram oxalate, and for which the rate was at least twice the placebo rate, were nausea (2%), insomnia (1%), and fatigue (1%). Incidence of Adverse Reactions in Placebo-Controlled Clinical Trials Major Depressive Disorder Pediatrics (6 to 17 years) The overall profile of adverse reactions in pediatric patients was generally similar to that seen in adult studies, as shown in Table 2. However, the following adverse reactions (excluding those which appear in Table 2 and those for which the coded terms were uninformative or misleading) were reported at an incidence of at least 2% for escitalopram oxalate and greater than placebo: back pain, urinary tract infection, vomiting, and nasal congestion. Adults The most commonly observed adverse reactions in escitalopram oxalate patients (incidence of approximately 5% or greater and approximately twice the incidence in placebo patients) were insomnia, ejaculation disorder (primarily ejaculatory delay), nausea, sweating increased, fatigue, and somnolence. Table 2 enumerates the incidence, rounded to the nearest percent, of treatment-emergent adverse events that occurred among 715 depressed patients who received escitalopram oxalate at doses ranging from 10 to 20 mg/day in placebo-controlled trials. Events included are those occurring in 2% or more of patients treated with escitalopram oxalate and for which the incidence in patients treated with escitalopram oxalate was greater than the incidence in placebo-treated patients. TABLE 2 Treatment-Emergent Adverse Reactions observed with a frequency of ≥ 2% and greater than placebo for Major Depressive Disorder Adverse Reaction Escitalopram oxalate Placebo (N=715) % (N=592) % 1 Primarily ejaculatory delay. 2 Denominator used was for males only (N=225 escitalopram oxalate; N=188 placebo). 3 Denominator used was for females only (N=490 escitalopram oxalate; N=404 placebo). Autonomic Nervous System Disorders Dry Mouth 6% 5% Sweating Increased 5% 2% Central & Peripheral Nervous System Disorders Dizziness 5% 3% Gastrointestinal Disorders Nausea 15% 7% Diarrhea 8% 5% Constipation 3% 1% Indigestion 3% 1% Abdominal Pain 2% 1% General Influenza-like Symptoms 5% 4% Fatigue 5% 2% Psychiatric Disorders Insomnia 9% 4% Somnolence 6% 2% Appetite Decreased 3% 1% Libido Decreased 3% 1% Respiratory System Disorders Rhinitis 5% 4% Sinusitis 3% 2% Urogenital Ejaculation Disorder 1,2 9% <1% Impotence 2 3% <1% Anorgasmia 3 2% <1% Generalized Anxiety Disorder Adults The most commonly observed adverse reactions in escitalopram oxalate patients (incidence of approximately 5% or greater and approximately twice the incidence in placebo patients) were nausea, ejaculation disorder (primarily ejaculatory delay), insomnia, fatigue, decreased libido, and anorgasmia. Table 3 enumerates the incidence, rounded to the nearest percent of treatment-emergent adverse events that occurred among 429 GAD patients who received escitalopram oxalate 10 to 20 mg/day in placebo-controlled trials. Events included are those occurring in 2% or more of patients treated with escitalopram oxalate and for which the incidence in patients treated with escitalopram oxalate was greater than the incidence in placebo-treated patients. TABLE 3 Treatment-Emergent Adverse Reactions observed with a frequency of ≥ 2% and greater than placebo for Generalized Anxiety Disorder Adverse Reactions Escitalopram oxalate Placebo (N=429) % (N=427) % 1 Primarily ejaculatory delay. 2 Denominator used was for males only (N=182 escitalopram oxalate; N=195 placebo). 3 Denominator used was for females only (N=247 escitalopram oxalate; N=232 placebo). Autonomic Nervous System Disorders Dry Mouth 9% 5% Sweating Increased 4% 1% Central & Peripheral Nervous System Disorders Headache 24% 17% Paresthesia 2% 1% Gastrointestinal Disorders Nausea 18% 8% Diarrhea 8% 6% Constipation 5% 4% Indigestion 3% 2% Vomiting 3% 1% Abdominal Pain 2% 1% Flatulence 2% 1% Toothache 2% 0% General Fatigue 8% 2% Influenza-like Symptoms 5% 4% Musculoskeletal System Disorder Neck/Shoulder Pain 3% 1% Psychiatric Disorders Somnolence 13% 7% Insomnia 12% 6% Libido Decreased 7% 2% Dreaming Abnormal 3% 2% Appetite Decreased 3% 1% Lethargy 3% 1% Respiratory System Disorders Yawning 2% 1% Urogenital Ejaculation Disorder 1,2 14% 2% Anorgasmia 3 6% <1% Menstrual Disorder 2% 1% Dose Dependency of Adverse Reactions The potential dose dependency of common adverse reactions (defined as an incidence rate of ≥5% in either the 10 mg or 20 mg escitalopram oxalate groups) was examined on the basis of the combined incidence of adverse reactions in two fixed-dose trials. The overall incidence rates of adverse events in 10 mg escitalopram oxalate-treated patients (66%) was similar to that of the placebo-treated patients (61%), while the incidence rate in 20 mg/day escitalopram oxalate-treated patients was greater (86%). Table 4 shows common adverse reactions that occurred in the 20 mg/day escitalopram oxalate group with an incidence that was approximately twice that of the 10 mg/day escitalopram oxalate group and approximately twice that of the placebo group. TABLE 4 Incidence of Common Adverse Reactions in Patients with Major Depressive Disorder Adverse Reaction Placebo 10 mg/day 20 mg/day Escitalopram oxalate Escitalopram oxalate (N=311) (N=310) (N=125) Insomnia 4% 7% 14% Diarrhea 5% 6% 14% Dry Mouth 3% 4% 9% Somnolence 1% 4% 9% Dizziness 2% 4% 7% Sweating Increased <1% 3% 8% Constipation 1% 3% 6% Fatigue 2% 2% 6% Indigestion 1% 2% 6% Male and Female Sexual Dysfunction with SSRIs Although changes in sexual desire, sexual performance, and sexual satisfaction often occur as manifestations of a psychiatric disorder, they may also be a consequence of pharmacologic treatment. In particular, some evidence suggests that SSRIs can cause such untoward sexual experiences. Reliable estimates of the incidence and severity of untoward experiences involving sexual desire, performance, and satisfaction are difficult to obtain, however, in part because patients and physicians may be reluctant to discuss them. Accordingly, estimates of the incidence of untoward sexual experience and performance cited in product labeling are likely to underestimate their actual incidence. TABLE 5 Incidence of Sexual Side Effects in Placebo-Controlled Clinical Trials Adverse Event Escitalopram oxalate Placebo In Males Only (N=407) (N=383) Ejaculation Disorder (primarily ejaculatory delay) 12% 1% Libido Decreased 6% 2% Impotence 2% <1% In Females Only (N=737) (N=636) Libido Decreased 3% 1% Anorgasmia 3% <1% There are no adequately designed studies examining sexual dysfunction with escitalopram treatment. Priapism has been reported with all SSRIs. While it is difficult to know the precise risk of sexual dysfunction associated with the use of SSRIs, physicians should routinely inquire about such possible side effects. Vital Sign Changes Escitalopram oxalate and placebo groups were compared with respect to (1) mean change from baseline in vital signs (pulse, systolic blood pressure, and diastolic blood pressure) and (2) the incidence of patients meeting criteria for potentially clinically significant changes from baseline in these variables. These analyses did not reveal any clinically important changes in vital signs associated with escitalopram oxalate treatment. In addition, a comparison of supine and standing vital sign measures in subjects receiving escitalopram oxalate indicated that escitalopram oxalate treatment is not associated with orthostatic changes. Weight Changes Patients treated with escitalopram oxalate in controlled trials did not differ from placebo-treated patients with regard to clinically important change in body weight. Laboratory Changes Escitalopram oxalate and placebo groups were compared with respect to (1) mean change from baseline in various serum chemistry, hematology, and urinalysis variables, and (2) the incidence of patients meeting criteria for potentially clinically significant changes from baseline in these variables. These analyses revealed no clinically important changes in laboratory test parameters associated with escitalopram oxalate treatment. ECG Changes Electrocardiograms from escitalopram oxalate (N=625) and placebo (N=527) groups were compared with respect to outliers defined as subjects with QTc changes over 60 msec from baseline or absolute values over 500 msec post-dose, and subjects with heart rate increases to over 100 bpm or decreases to less than 50 bpm with a 25% change from baseline (tachycardic or bradycardic outliers, respectively). None of the patients in the escitalopram oxalate group had a QTcF interval >500 msec or a prolongation >60 msec compared to 0.2% of patients in the placebo group. The incidence of tachycardic outliers was 0.2% in the escitalopram oxalate and the placebo group. The incidence of bradycardic outliers was 0.5% in the escitalopram oxalate group and 0.2% in the placebo group. QTcF interval was evaluated in a randomized, placebo and active (moxifloxacin 400 mg) controlled cross-over, escalating multiple dose study in 113 healthy subjects. The maximum mean (95% upper confidence bound) difference from placebo arm were 4.5 (6.4) and 10.7 (12.7) msec for 10 mg and supratherapeutic 30 mg escitalopram given once daily, respectively. Based on the established exposure-response relationship, the predicted QTcF change from placebo arm (95% confidence interval) under the C max for the dose of 20 mg is 6.6 (7.9) msec. Escitalopram 30 mg given once daily resulted in mean C max of 1.7-fold higher than the mean C max for the maximum recommended therapeutic dose at steady state (20 mg). The exposure under supratherapeutic 30 mg dose is similar to the steady state concentrations expected in CYP2C19 poor metabolizers following a therapeutic dose of 20 mg. Other Reactions Observed During the Premarketing Evaluation of Escitalopram Oxalate Following is a list of treatment-emergent adverse events, as defined in the introduction to the ADVERSE REACTIONS section, reported by the 1428 patients treated with escitalopram oxalate for periods of up to one year in double-blind or open-label clinical trials during its premarketing evaluation. The listing does not include those events already listed in Tables 2 & 3 , those events for which a drug cause was remote and at a rate less than 1% or lower than placebo, those events which were so general as to be uninformative, and those events reported only once which did not have a substantial probability of being acutely life threatening. Events are categorized by body system. Events of major clinical importance are described in the Warnings and Precautions section (5) . Cardiovascular - hypertension, palpitation. Central and Peripheral Nervous System Disorders - light-headed feeling, migraine. Gastrointestinal Disorders - abdominal cramp, heartburn, gastroenteritis. General - allergy, chest pain, fever, hot flushes, pain in limb. Metabolic and Nutritional Disorders - increased weight. Musculoskeletal System Disorders - arthralgia, myalgia, jaw stiffness. Psychiatric Disorders - appetite increased, concentration impaired, irritability. Reproductive Disorders/Female - menstrual cramps, menstrual disorder. Respiratory System Disorders - bronchitis, coughing, nasal congestion, sinus congestion, sinus headache. Skin and Appendages Disorders - rash. Special Senses - vision blurred, tinnitus. Urinary System Disorders - urinary frequency, urinary tract infection. 6.2 Post-Marketing Experience Adverse Reactions Reported Subsequent to the Marketing of Escitalopram The following adverse reactions have been identified during post-approval use of escitalopram oxalate. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Blood and Lymphatic System Disorders: anemia, agranulocytis, aplastic anemia, hemolytic anemia, idiopathic thrombocytopenia purpura, leukopenia, thrombocytopenia. Cardiac Disorders: atrial fibrillation, bradycardia, cardiac failure, myocardial infarction, tachycardia, torsade de pointes, ventricular arrhythmia, ventricular tachycardia. Ear and Labyrinth Disorders: vertigo. Endocrine Disorders: diabetes mellitus, hyperprolactinemia, SIADH. Eye Disorders: angle closure glaucoma, diplopia, mydriasis, visual disturbance. Gastrointestinal Disorder: dysphagia, gastrointestinal hemorrhage, gastroesophageal reflux, pancreatitis, rectal hemorrhage. General Disorders and Administration Site Conditions: abnormal gait, asthenia, edema, fall, feeling abnormal, malaise. Hepatobiliary Disorders: fulminant hepatitis, hepatic failure, hepatic necrosis, hepatitis. Immune System Disorders: allergic reaction, anaphylaxis. Investigations: bilirubin increased, decreased weight, electrocardiogram QT prolongation, hepatic enzymes increased, hypercholesterolemia, INR increased, prothrombin decreased. Metabolism and Nutrition Disorders: hyperglycemia, hypoglycemia, hypokalemia, hyponatremia. Musculoskeletal and Connective Tissue Disorders: muscle cramp, muscle stiffness, muscle weakness, rhabdomyolysis. Nervous System Disorders: akathisia, amnesia, ataxia, choreoathetosis, cerebrovascular accident, dysarthria, dyskinesia, dystonia, extrapyramidal disorders, grand mal seizures (or convulsions), hypoaesthesia, myoclonus, nystagmus, Parkinsonism, restless legs, seizures, syncope, tardive dyskinesia, tremor. Pregnancy, Puerperium and Perinatal Conditions: spontaneous abortion. Psychiatric Disorders: acute psychosis, aggression, agitation, anger, anxiety, apathy, completed suicide, confusion, depersonalization, depression aggravated, delirium, delusion, disorientation, feeling unreal, hallucinations (visual and auditory), mood swings, nervousness, nightmare, panic reaction, paranoia, restlessness, self-harm or thoughts of self-harm, suicide attempt, suicidal ideation, suicidal tendency. Renal and Urinary Disorders: acute renal failure, dysuria, urinary retention. Reproductive System and Breast Disorders: menorrhagia, priapism. Respiratory, Thoracic and Mediastinal Disorders: dyspnea, epistaxis, pulmonary embolism, pulmonary hypertension of the newborn. Skin and Subcutaneous Tissue Disorders: alopecia, angioedema, dermatitis, ecchymosis, erythema multiforme, photosensitivity reaction, Stevens Johnson Syndrome, toxic epidermal necrolysis, urticaria. Vascular Disorders: deep vein thrombosis, flushing, hypertensive crisis, hypotension, orthostatic hypotension, phlebitis, thrombosis.

12.3 Pharmacokinetics The single- and multiple-dose pharmacokinetics of escitalopram are linear and dose-proportional in a dose range of 10 to 30 mg/day. Biotransformation of escitalopram is mainly hepatic, with a mean terminal half-life of about 27 to 32 hours. With once-daily dosing, steady state plasma concentrations are achieved within approximately one week. At steady state, the extent of accumulation of escitalopram in plasma in young healthy subjects was 2.2 to 2.5 times the plasma concentrations observed after a single dose. The tablet and the oral solution dosage forms of escitalopram oxalate are bioequivalent. Absorption and Distribution Following a single oral dose (20 mg tablet or solution) of escitalopram, peak blood levels occur at about 5 hours. Absorption of escitalopram is not affected by food. The absolute bioavailability of citalopram is about 80% relative to an intravenous dose, and the volume of distribution of citalopram is about 12 L/kg. Data specific on escitalopram are unavailable. The binding of escitalopram to human plasma proteins is approximately 56%. Metabolism and Elimination Following oral administrations of escitalopram, the fraction of drug recovered in the urine as escitalopram and S-demethylcitalopram (S-DCT) is about 8% and 10%, respectively. The oral clearance of escitalopram is 600 mL/min, with approximately 7% of that due to renal clearance. Escitalopram is metabolized to S-DCT and S-didemethylcitalopram (S-DDCT). In humans, unchanged escitalopram is the predominant compound in plasma. At steady state, the concentration of the escitalopram metabolite S-DCT in plasma is approximately one-third that of escitalopram. The level of S-DDCT was not detectable in most subjects. In vitro studies show that escitalopram is at least 7 and 27 times more potent than S-DCT and S-DDCT, respectively, in the inhibition of serotonin reuptake, suggesting that the metabolites of escitalopram do not contribute significantly to the antidepressant actions of escitalopram. S-DCT and S-DDCT also have no or very low affinity for serotonergic (5-HT 1-7 ) or other receptors including alpha- and beta-adrenergic, dopamine (D 1-5 ), histamine (H 1-3 ), muscarinic (M 1-5 ), and benzodiazepine receptors. S-DCT and S-DDCT also do not bind to various ion channels including Na + , K + , Cl - , and Ca ++ channels. In vitro studies using human liver microsomes indicated that CYP3A4 and CYP2C19 are the primary isozymes involved in the N-demethylation of escitalopram. Population Subgroups Age Adolescents - In a single dose study of 10 mg escitalopram, AUC of escitalopram decreased by 19%, and C max increased by 26% in healthy adolescent subjects (12 to 17 years of age) compared to adults. Following multiple dosing of 40 mg/day citalopram, escitalopram elimination half-life, steady-state C max and AUC were similar in patients with MDD (12 to 17 years of age) compared to adult patients. No adjustment of dosage is needed in adolescent patients. Elderly - Escitalopram pharmacokinetics in subjects ≥ 65 years of age were compared to younger subjects in a single-dose and a multiple-dose study. Escitalopram AUC and half-life were increased by approximately 50% in elderly subjects, and C max was unchanged. 10 mg is the recommended dose for elderly patients [see Dosage and Administration (2.3) ] . Gender - Based on data from single- and multiple-dose studies measuring escitalopram in elderly, young adults, and adolescents, no dosage adjustment on the basis of gender is needed. Reduced hepatic function - Citalopram oral clearance was reduced by 37% and half-life was doubled in patients with reduced hepatic function compared to normal subjects. 10 mg is the recommended dose of escitalopram for most hepatically impaired patients [see Dosage and Administration (2.3) ] . Reduced renal function - In patients with mild to moderate renal function impairment, oral clearance of citalopram was reduced by 17% compared to normal subjects. No adjustment of dosage for such patients is recommended. No information is available about the pharmacokinetics of escitalopram in patients with severely reduced renal function (creatinine clearance < 20 mL/min). Drug-Drug Interactions In vitro enzyme inhibition data did not reveal an inhibitory effect of escitalopram on CYP3A4, -1A2, -2C9, -2C19, and -2E1. Based on in vitro data, escitalopram would be expected to have little inhibitory effect on in vivo metabolism mediated by these cytochromes. While in vivo data to address this question are limited, results from drug interaction studies suggest that escitalopram, at a dose of 20 mg, has no 3A4 inhibitory effect and a modest 2D6 inhibitory effect. See Drug Interactions (7.18) for more detailed information on available drug interaction data.