Fluvoxamine-WGR

What it is

Fluvoxamine-WGR is a selective serotonin reuptake inhibitor (SSRI) antidepressant agent that is chemically unrelated to tricyclic antidepressants and other serotonin reuptake inhibitors as it is a monocyclic compound. Fluvoxamine-WGR tablets contain 50 mg or 100 mg of fluvoxamine maleate. The mechanism of action is believed to be related to its ability to selectively inhibit presynaptic reuptake of serotonin, thus increasing serotonin concentrations within the synaptic cleft, with minimal interference with noradrenergic and dopaminergic processes.

Approved indications

— Treatment of major depression in adults. — Treatment of obsessive compulsive disorder (OCD) in children aged 8 years and older, adolescents, and adults.

Dosing overview

When stopping treatment, the dose should be gradually reduced over at least one or two weeks to reduce the risk of withdrawal reactions.

Key safety warnings

A major depressive episode may be the initial presentation of bipolar disorder. Treating such an episode with an antidepressant alone may increase the likelihood of a mixed or manic episode in patients at risk for bipolar disorder. Prior to initiating treatment, patients should be adequately screened with a detailed psychiatric history including family history of suicide, bipolar disorder, and depression. The risk of suicide attempt is inherent in depression. Patients may experience worsening depressive symptoms and emergence of suicidal ideation and behaviours whether or not taking antidepressants. Patients should be closely monitored for clinical worsening and suicidality, especially at the beginning of treatment or at times of dose changes. Pooled analyses of 24 short-term placebo-controlled trials in 4400 children and adolescents revealed a greater risk of adverse events representing suicidal behaviour or thinking during the first few months of treatment in those receiving antidepressants, with an average risk of 4% compared to 2% for placebo. Fluvoxamine has been associated with development of akathisia, most likely occurring within the first few weeks of treatment. Although fluvoxamine has no pro-convulsive properties in animal studies, caution is recommended in patients with a history of convulsive disorders. Fluvoxamine should be avoided in patients with unstable epilepsy, and treatment should be discontinued if seizures occur or seizure frequency increases. Serious skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, have been reported with fluvoxamine, with patients at highest risk early in the course of therapy. If skin reactions occur, fluvoxamine should be discontinued immediately. Serotonin syndrome or neuroleptic malignant syndrome-like events may occur with SSRIs, particularly in combination with monoamine oxidase inhibitors or other serotonergic agents. Symptoms include rapid onset of neuromuscular excitation, altered mental status, and autonomic dysfunction. Treatment should be discontinued if such events occur.

Contraindications

Fluvoxamine is contraindicated in combination with tizanidine. Fluvoxamine should not be used with monoamine oxidase inhibitors (MAOIs), reversible MAOI (moclobemide), or linezolid within 14 days of discontinuing treatment with a MAOI. At least one week should be allowed after stopping fluvoxamine before starting a MAOI. Fluvoxamine tablets should not be used with pimozide, ramelteon, or cisapride. Fluvoxamine tablets are contraindicated in patients with hypersensitivity to any component of the product. Fluvoxamine should not be used by nursing mothers, as it has been shown to increase postnatal mortality in rats at doses greater than 1 mg/kg/day and is excreted in human milk.

Regulatory history

Fluvoxamine-WGR was first registered on the Australian Register of Therapeutic Goods on 14 January 2009, with both the 50 mg and 100 mg tablet formulations registered under licence category RE.