CYMBALTA (Duloxetine Delayed-Release Capsules)

CYMBALTA (Duloxetine Delayed-Release Capsules)

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CYMBALTA (Duloxetine Delayed-Release Capsules)

CYMBALTA® (duloxetine delayed-release capsules) is a selective serotonin and norepinephrine reuptake inhibitor (SSNRI) for oral administration. Its chemical designation is (+)-(S)-N-methyl-γ-(1-naphthyloxy)-2-thiophenepropylamine hydrochloride. The empirical formula is C18H19NOS•HCl, which corresponds to a molecular weight of 333.88.

Indications and usage

CYMBALTA® is a serotonin and norepinephrine reuptake inhibitor (SNRI) indicated for:

  • Major Depressive Disorder (MDD)
  • Generalized Anxiety Disorder (GAD)
  • Diabetic Peripheral Neuropathic Pain (DPNP)
  • Fibromyalgia (FM)
  • Chronic Musculoskeletal Pain

Mechanism of Action

Although the exact mechanisms of the antidepressant, central pain inhibitory and anxiolytic actions of duloxetine in humans are unknown, these actions are believed to be related to its potentiation of serotonergic and noradrenergic activity in the CNS.

Pharmacodynamics

Preclinical studies have shown that duloxetine is a potent inhibitor of neuronal serotonin and norepinephrine reuptake and a less potent inhibitor of dopamine reuptake. Duloxetine has no significant affinity for dopaminergic, adrenergic, cholinergic, histaminergic, opioid, glutamate, and GABA receptors in vitro. Duloxetine does not inhibit monoamine oxidase (MAO).

CYMBALTA is in a class of drugs known to affect urethral resistance. If symptoms of urinary hesitation develop during treatment with CYMBALTA, consideration should be given to the possibility that they might be drug-related.

Dosage and administration

Swallow CYMBALTA whole. Do not chew or crush. Do not open the capsule and sprinkle its contents on food or mix with liquids. All of these might affect the enteric coating. CYMBALTA can be given without regard to meals. If a dose of CYMBALTA is missed, take the missed dose as soon as it is remembered. If it is almost time for the next dose, skip the missed dose and take the next dose at the regular time. Do not take two doses of CYMBALTA at the same time.

Dosage for Treatment of Major Depressive Disorder: Administer CYMBALTA at a total dose of 40 mg/day (given as 20 mg twice daily) to 60 mg/day (given either once daily or as 30 mg twice daily). For some patients, it may be desirable to start at 30 mg once daily for 1 week, to allow patients to adjust to the medication before increasing to 60 mg once daily. While a 120 mg/day dose was shown to be effective, there is no evidence that doses greater than 60 mg/day confer any additional benefits.

Dosage for Treatment of Generalized Anxiety Disorder

Adults — For most patients, initiate CYMBALTA 60 mg once daily. For some patients, it may be desirable to start at 30 mg once daily for 1 week, to allow patients to adjust to the medication before increasing to 60 mg once daily. While a 120 mg once daily dose was shown to be effective, there is no evidence that doses greater than 60 mg/day confer additional benefit.

Elderly — Initiate CYMBALTA at a dose of 30 mg once daily for 2 weeks before considering an increase to the target dose of 60 mg. Thereafter, patients may benefit from doses above 60 mg once daily. If a decision is made to increase the dose beyond 60 mg once daily, increase dose in increments of 30 mg once daily. The maximum dose studied was 120 mg per day.

Children and Adolescents (7 to 17 years of age) — Initiate CYMBALTA at a dose of 30 mg once daily for 2 weeks before considering an increase to 60 mg. The recommended dose range is 30 to 60 mg once daily. Some patients may benefit from doses above 60 mg once daily. If a decision is made to increase the dose beyond 60 mg once daily, increase dose in increments of 30 mg once daily. The maximum dose studied was 120 mg per day

Dosage for Treatment of Diabetic Peripheral Neuropathic Pain: Administer CYMBALTA 60 mg once daily. There is no evidence that doses higher than 60 mg confer additional significant benefit and the higher dose is clearly less well tolerated. For patients for whom tolerability is a concern, a lower starting dose may be considered.

Dosage for Treatment of Fibromyalgia: Administer CYMBALTA 60 mg once daily. Begin treatment at 30 mg once daily for 1 week, to allow patients to adjust to the medication before increasing to 60 mg once daily. Some patients may respond to the starting dose.

Dosage for Treatment of Chronic Musculoskeletal Pain: Administer CYMBALTA 60 mg once daily. Begin treatment at 30 mg for one week, to allow patients to adjust to the medication before increasing to 60 mg once daily.

Discontinuing CYMBALTA

Adverse reactions after discontinuation of CYMBALTA, after abrupt or tapered discontinuation, include: dizziness, headache, nausea, diarrhea, paresthesia, irritability, vomiting, insomnia, anxiety, hyperhidrosis, and fatigue. A gradual reduction in dosage rather than abrupt cessation is recommended whenever possible

Contraindications

Monoamine Oxidase Inhibitors (MAOIs) — The use of MAOIs intended to treat psychiatric disorders with CYMBALTA or within 5 days of stopping treatment with CYMBALTA is contraindicated because of an increased risk of serotonin syndrome. The use of CYMBALTA within 14 days of stopping an MAOI intended to treat psychiatric disorders is also contraindicated.

Starting CYMBALTA in a patient who is being treated with MAOIs such as linezolid or intravenous methylene blue is also contraindicated because of an increased risk of serotonin syndrome

Warnings and precautions

  • Hepatotoxicity: Hepatic failure, sometimes fatal, has been reported in patients treated with CYMBALTA. CYMBALTA should be discontinued in patients who develop jaundice or other evidence of clinically significant liver dysfunction and should not be resumed unless another cause can be established. CYMBALTA should not be prescribed to patients with substantial alcohol use or evidence of chronic liver disease
  • Orthostatic Hypotension, Falls and Syncope: Cases have been reported with CYMBALTA therapy
  • Serotonin Syndrome: Serotonin syndrome has been reported with SSRIs and SNRIs, including with CYMBALTA, both when taken alone, but especially when co-administered with other serotonergic agents (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, amphetamines, and St. John’s Wort). If such symptoms occur, discontinue CYMBALTA and initiate supportive treatment. If concomitant use of CYMBALTA with other serotonergic drugs is clinically warranted, patients should be made aware of a potential increased risk for serotonin syndrome, particularly during treatment initiation and dose increases
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  • Abnormal Bleeding: CYMBALTA may increase the risk of bleeding events. Patients should be cautioned about the risk of bleeding associated with the concomitant use of CYMBALTA and NSAIDs, aspirin, or other drugs that affect coagulation
  • Severe Skin Reactions: Severe skin reactions, including erythema multiforme and Stevens-Johnson Syndrome (SJS), can occur with CYMBALTA. CYMBALTA should be discontinued at the first appearance of blisters, peeling rash, mucosal erosions, or any other sign of hypersensitivity if no other etiology can be identified.
  • Discontinuation: May result in symptoms, including dizziness, headache, nausea, diarrhea, paresthesia, irritability, vomiting, insomnia, anxiety, hyperhidrosis, and fatigue
  • Activation of mania or hypomania has occurred
  • Angle-Closure Glaucoma: Angle-closure glaucoma has occurred in patients with untreated anatomically narrow angles treated with antidepressants.
  • Seizures: Prescribe with care in patients with a history of seizure disorder
  • Blood Pressure: Monitor blood pressure prior to initiating treatment and periodically throughout treatment
  • Inhibitors of CYP1A2 or Thioridazine: Should not administer with CYMBALTA
  • Hyponatremia: Cases of hyponatremia have been reported
  • Glucose Control in Diabetes: In diabetic peripheral neuropathic pain patients, small increases in fasting blood glucose, and HbA1c have been observed
  • Conditions that Slow Gastric Emptying: Use cautiously in these patients
  • Urinary Hesitation and Retention

Drug interactions

Inhibitors of CYP1A2: When duloxetine 60 mg was co-administered with fluvoxamine 100 mg, a potent CYP1A2 inhibitor, to male subjects (n=14) duloxetine AUC was increased approximately 6-fold, the Cmax was increased about 2.5-fold, and duloxetine t ½  was increased approximately 3-fold. Other drugs that inhibit CYP1A2 metabolism include cimetidine and quinolone antimicrobials such as ciprofloxacin and enoxacin.

Inhibitors of CYP2D6: Concomitant use of duloxetine (40 mg once daily) with paroxetine (20 mg once daily) increased the concentration of duloxetine AUC by about 60%, and greater degrees of inhibition are expected with higher doses of paroxetine. Similar effects would be expected with other potent CYP2D6 inhibitors (e.g., fluoxetine, quinidine)

Drugs that Interfere with Hemostasis (e.g., NSAIDs, Aspirin, and Warfarin)

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 this risk of bleeding.

Altered anticoagulant effects, including increased bleeding, have been reported when SSRIs or SNRIs are co-administered with warfarin.

Drugs Metabolized by CYP2D6: Duloxetine is a moderate inhibitor of CYP2D6. When duloxetine was administered (at a dose of 60 mg twice daily) in conjunction with a single 50 mg dose of desipramine, a CYP2D6 substrate, the AUC of desipramine increased 3-fold

Use in specific populations

Pregnancy: There are no adequate and well-controlled studies of CYMBALTA administration in pregnant women.

Fetal/Neonatal Adverse Reaction: Neonates exposed during pregnancy to serotonin – norepinephrine reuptake inhibitors (SNRIs) or selective serotonin reuptake inhibitors (SSRIs) have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding which 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 the SNRIs or SSRIs, or possibly, a drug discontinuation syndrome. It should be noted that, in some cases, the clinical picture is consistent with serotonin syndrome.

Nursing Mothers: CYMBALTA is present in human milk. In a published study, lactating women who were weaning their infants were given CYMBALTA. At steady state, the concentration of CYMBALTA in breast milk was approximately 25% that of maternal plasma. The estimated daily infant dose was approximately 0.14% of the maternal dose. The developmental and health benefits of human milk feeding should be considered along with the mother’s clinical need for CYMBALTA and any potential adverse effects on the milk-fed child from the drug or from the underlying maternal condition. Exercise caution when CYMBALTA is administered to a nursing woman.

Hepatic Impairment: Patients with clinically evident hepatic impairment have decreased duloxetine metabolism and elimination. After a single 20 mg dose of CYMBALTA, 6 cirrhotic patients with moderate liver impairment (Child-Pugh Class B) had a mean plasma duloxetine clearance about 15% that of age- and gender-matched healthy subjects, with a 5-fold increase in mean exposure (AUC). Although Cmax was similar to normals in the cirrhotic patients, the half-life was about 3 times longer

Overdosage

In postmarketing experience, fatal outcomes have been reported for acute overdoses, primarily with mixed overdoses, but also with duloxetine only, at doses as low as 1000 mg. Signs and symptoms of overdose (duloxetine alone or with mixed drugs) included somnolence, coma, serotonin syndrome, seizures, syncope, tachycardia, hypotension, hypertension, and vomiting.

Management of Overdose

There is no specific antidote to CYMBALTA, but if serotonin syndrome ensues, specific treatment (such as with cyproheptadine and/or temperature control) may be considered. In case of acute overdose, treatment should consist of those general measures employed in the management of overdose with any drug.

An adequate airway, oxygenation, and ventilation should be assured, and cardiac rhythm and vital signs should be monitored. Induction of emesis is not recommended. Gastric lavage with a large-bore orogastric tube with appropriate airway protection, if needed, may be indicated if performed soon after ingestion or in symptomatic patients

Activated charcoal may be useful in limiting absorption of duloxetine from the gastrointestinal tract. Administration of activated charcoal has been shown to decrease AUC and Cmax by an average of one-third, although some subjects had a limited effect of activated charcoal. Due to the large volume of distribution of this drug, forced diuresis, dialysis, hemoperfusion, and exchange transfusion are unlikely to be beneficial.

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