Overview

Duloxetine is a selective serotonin and norepinephrine reuptake inhibitor antidepressant (SSNRI). Duloxetine affects chemicals in the brain that may become unbalanced and cause depression. Duloxetine is used to treat major depressive disorder and general anxiety disorder. Duloxetine is also used to treat fibromyalgia (a chronic pain disorder), or chronic muscle or joint pain (such as low back pain and osteoarthritis pain). Duloxetine is also used to treat pain caused by nerve damage in people with diabetes (diabetic neuropathy).

Warnings

Do NOT use Duloxetine HCL if:

you are allergic to any ingredient in duloxetine delayed-release Tablet

you have severe kidney problems, chronic liver disease, or cirrhosis

you are taking or have taken linezolid or a monoamine oxidase inhibitor (MAOI) (eg, phenelzine) within the last 14 days.

you are taking thioridazine

Contraindications

The use of MAOIs intended to treat psychiatric disorders with Duloxetine or within 5 days of stopping treatment with Duloxetine is contraindicated because of an increased risk of serotonin syndrome. The use of Duloxetine within 14 days of stopping an MAOI intended to treat psychiatric disorders is also contraindicated.

Starting Duloxetine 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.

Side Effects

drowsiness, dizziness, problems with thinking or memory, tired feeling, muscle weakness, loss of balance or coordination, slurred speech, drooling or dry mouth, sore gums, runny or stuffy nose, loss of appetite, nausea, diarrhea, constipation, blurred vision, headache.

Dosage

Oral:
Disclaimer:To be taken only after consulting with the doctor.

Storage

Tablets should be kept at room temperature, between 15 C and 30 C (59 F and 86 F).

Pharmacology

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.

Pharmacokinetics

Duloxetine has an elimination half-life of about 12 hours (range 8 to 17 hours) and its pharmacokinetics are dose proportional over the therapeutic range. Steady-state plasma concentrations are typically achieved after 3 days of dosing. Elimination of duloxetine is mainly through hepatic metabolism involving two P450 isozymes, CYP1A2 and CYP2D6.

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

Interactions

Increased risk of serotonin syndrome w/ TCA, SSRI, SNRI, lithium. May increase bleeding risk w/ aspirin, NSAIDs, warfarin and other anticoagulants.
Potentially Fatal: Increased risk of serotonin syndrome w/ MAOIs, linezolid and methylene blue. Increased serum levels and risk of toxicity w/ potent CYP1A2 inhibitors (e.g. ciprofloxacin, enoxacin).