Fevarin: Uses, Dosage & Side Effects

What Is Fevarin and What Is It Used For?

Fevarin belongs to the class of medications known as selective serotonin reuptake inhibitors (SSRIs), which are among the most widely prescribed antidepressants worldwide. The active substance, fluvoxamine maleate, works by selectively blocking the reuptake of the neurotransmitter serotonin (5-hydroxytryptamine, or 5-HT) in the brain. By preventing serotonin from being reabsorbed back into nerve cells, fluvoxamine increases the amount of serotonin available in the synaptic cleft — the space between nerve cells where chemical signalling occurs. This enhanced serotonergic activity is believed to underlie the drug's antidepressant and anti-obsessional effects.

In addition to its action on the serotonin transporter, fluvoxamine is a potent agonist of the sigma-1 receptor, a unique intracellular receptor involved in neuronal signalling, neuroprotection, and modulation of other neurotransmitter systems. This sigma-1 receptor activity distinguishes fluvoxamine from other SSRIs and may contribute to its particular efficacy in treating OCD and anxiety-related conditions. Research published in the Journal of Clinical Psychiatry has suggested that sigma-1 receptor agonism may enhance neuroplasticity and have additional anti-inflammatory properties.

Fluvoxamine has minimal affinity for alpha-adrenergic, beta-adrenergic, muscarinic cholinergic, dopaminergic, histaminergic, serotonergic (5-HT1 or 5-HT2), or benzodiazepine receptors. This relatively selective pharmacological profile accounts for its generally favourable side effect profile compared to older antidepressant classes such as tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs).

Approved Indications

Major Depressive Disorder (MDD): Fevarin is approved for the treatment of episodes of major depression in adults. Depression is characterised by persistent low mood, loss of interest in activities, changes in appetite and sleep patterns, fatigue, feelings of worthlessness or guilt, difficulty concentrating, and in severe cases, thoughts of self-harm or suicide. Fluvoxamine helps alleviate these symptoms by restoring the balance of serotonin in the brain. Clinical trials have demonstrated that fluvoxamine is as effective as other SSRIs and tricyclic antidepressants in treating moderate-to-severe depression, with the added advantage of fewer anticholinergic and cardiovascular side effects.

Obsessive-Compulsive Disorder (OCD): Fevarin is approved for the treatment of OCD in both adults and children aged 8 years and older. OCD is a chronic condition characterised by recurrent, intrusive thoughts (obsessions) and repetitive behaviours or mental acts (compulsions) performed to reduce anxiety. Fluvoxamine was one of the first SSRIs to receive regulatory approval for OCD treatment and remains a first-line pharmacological option recommended by the American Psychiatric Association (APA), the National Institute for Health and Care Excellence (NICE), and the World Health Organization (WHO). Meta-analyses published in the Lancet Psychiatry have confirmed SSRIs, including fluvoxamine, as the most effective pharmacological treatment for OCD.

It is important to note that in children and adolescents under 18 years of age, Fevarin should only be used for OCD — not for depression. The evidence for antidepressant efficacy in this age group is limited, and there is an increased risk of suicidal thoughts and behaviours in young people treated with antidepressants.

What Should You Know Before Taking Fevarin?

Contraindications

There are several situations in which Fevarin must not be used. Understanding these contraindications is essential for safe treatment. Do not take Fevarin if any of the following apply:

• Hypersensitivity: You are allergic to fluvoxamine maleate or any of the other ingredients in the tablets (including mannitol, maize starch, pregelatinised starch, sodium stearyl fumarate, colloidal anhydrous silica, hypromellose, macrogol 6000, talc, and titanium dioxide).
• MAO inhibitor therapy: You are currently taking or have recently taken a monoamine oxidase inhibitor (MAOI), including irreversible MAOIs (such as phenelzine, tranylcypromine) or reversible MAOIs (such as moclobemide), or the antibiotic linezolid, which also acts as a MAOI. Combining fluvoxamine with MAOIs can cause serotonin syndrome, a potentially fatal condition. Treatment with fluvoxamine should not be started until at least 2 weeks after stopping an irreversible MAOI. Treatment may be started the day after stopping a reversible MAOI such as moclobemide.
• Tizanidine: You are taking tizanidine, a muscle relaxant. Fluvoxamine strongly inhibits the CYP1A2 enzyme responsible for metabolising tizanidine, which can cause a dangerous increase in tizanidine blood levels, leading to severe hypotension and excessive sedation.
• Pimozide: You are taking pimozide, an antipsychotic medication. The combination carries a risk of serious cardiac arrhythmias due to elevated pimozide levels.
• Breastfeeding: Fluvoxamine passes into breast milk and may affect the nursing infant. Women who are breastfeeding should not take Fevarin.

Warnings and Precautions

Before starting Fevarin, inform your doctor if any of the following conditions apply to you, as special precautions may be necessary:

• Recent heart attack: Fluvoxamine should be used with caution in patients who have recently suffered a myocardial infarction.
• Epilepsy or seizure history: SSRIs can lower the seizure threshold. If you experience a seizure while taking Fevarin, treatment should be discontinued.
• Bleeding disorders: Fluvoxamine may impair platelet aggregation, increasing the risk of bleeding. This risk is heightened in patients taking anticoagulants, NSAIDs, or aspirin, and in those with a history of bleeding disorders.
• Diabetes: Fluvoxamine may affect blood glucose control. Diabetic patients may need dose adjustments of their antidiabetic medication.
• Electroconvulsive therapy (ECT): There is limited clinical experience with concurrent use of fluvoxamine and ECT. Caution is advised.
• History of mania: Fluvoxamine should be used with caution in patients with a history of mania or hypomania, as SSRIs may trigger manic episodes.
• Liver or kidney impairment: Patients with hepatic or renal insufficiency should start with a lower dose and be monitored carefully. Fluvoxamine is extensively metabolised by the liver, and impaired hepatic function can significantly increase drug exposure.
• Glaucoma: SSRIs may cause pupil dilation (mydriasis), which can increase intraocular pressure in patients with narrow-angle glaucoma.

Use in Children and Adolescents

Children and adolescents under 18 years of age should not take Fevarin for the treatment of depression. When used for OCD in this age group, there is an increased risk of suicidal behaviour, self-harm, hostility, aggression, and oppositional behaviour compared to adults. Despite this, a doctor may prescribe Fevarin for OCD in children aged 8 and older if it is considered the best treatment option. The long-term effects on growth, maturation, and cognitive and behavioural development have not been fully established in this age group.

Pregnancy and Breastfeeding

Experience with fluvoxamine use during pregnancy is limited. If you are pregnant, planning to become pregnant, or suspect you may be pregnant, do not take Fevarin unless your doctor has determined it is absolutely necessary after weighing the potential benefits against the risks.

Use of SSRIs during the last trimester of pregnancy may increase the risk of persistent pulmonary hypertension of the newborn (PPHN), a serious condition in which the baby has difficulty breathing and develops a bluish skin colour, typically within 24 hours of birth. Additionally, babies exposed to SSRIs late in pregnancy may experience neonatal withdrawal symptoms, including feeding difficulties, breathing problems, temperature instability, tremor, irritability, excessive crying, muscle stiffness or floppiness, lethargy, and seizures.

There may also be an increased risk of heavy vaginal bleeding shortly after delivery (postpartum haemorrhage), particularly in women with a history of bleeding disorders. Inform your midwife or doctor that you are taking fluvoxamine so they can provide appropriate monitoring.

Fluvoxamine passes into breast milk, and there is a risk of effects on the nursing infant. Breastfeeding is therefore not recommended during Fevarin treatment. Discuss alternative options with your healthcare provider.

Animal studies have shown that fluvoxamine may reduce sperm quality. While this effect has not been confirmed in humans, men planning to father children should discuss this potential risk with their physician.

Driving and Operating Machinery

Fevarin may cause drowsiness in some patients. You should not drive or operate heavy machinery until you know how the medication affects you. If you experience drowsiness, avoid activities that require full alertness.

How Does Fevarin Interact with Other Drugs?

Fluvoxamine has a particularly important drug interaction profile due to its potent inhibition of cytochrome P450 enzymes, especially CYP1A2 and CYP2C19, and to a lesser extent CYP2C9 and CYP3A4. This enzyme inhibition means that many commonly used medications are metabolised more slowly when taken with fluvoxamine, potentially leading to dangerously elevated blood levels and increased toxicity. Understanding these interactions is crucial for safe prescribing.

Major Interactions (Contraindicated)

Significant Interactions (Use with Caution)

Caffeine Interaction

An important and often overlooked interaction is with caffeine. Fluvoxamine is a potent inhibitor of CYP1A2, which is the primary enzyme responsible for caffeine metabolism. Patients who consume significant amounts of tea, coffee, or caffeinated soft drinks may experience substantially elevated caffeine levels, leading to tremor, nausea, palpitations, restlessness, and insomnia. Reducing caffeine intake while taking fluvoxamine is strongly advised. Research published in Clinical Pharmacology and Therapeutics has shown that fluvoxamine can increase the half-life of caffeine from approximately 5 hours to more than 30 hours.

Alcohol

Alcohol should be avoided during Fevarin treatment. The combination can cause increased drowsiness and impaired coordination, and alcohol may counteract the therapeutic benefits of the antidepressant.

What Is the Correct Dosage of Fevarin?

Fevarin dosage is individualised based on the condition being treated, patient age, response to treatment, and tolerability. Always follow your doctor's instructions and the directions on your prescription label. The tablets should be swallowed whole with water and may be taken with or without food. Do not chew the tablets. The tablets have a score line and can be split if your doctor instructs you to do so.

Adults (Over 18 Years)

Children and Adolescents (8 Years and Older)

Elderly Patients

Elderly patients should start at the lowest recommended dose and have their dose increased more slowly under careful medical supervision. The elderly may be more susceptible to side effects, particularly hyponatraemia (low blood sodium) and falls.

Patients with Liver or Kidney Impairment

Patients with reduced liver or kidney function should start with the lowest possible dose and be monitored carefully. Dose adjustments may be necessary, as impaired hepatic function can significantly slow the metabolism of fluvoxamine.

Duration of Treatment

Continue taking Fevarin for as long as your doctor recommends, even if you feel better. Your doctor will typically recommend continuing treatment for at least 6 months after symptoms have improved to ensure sustained remission. For OCD, long-term maintenance therapy is often necessary, as the condition tends to recur after medication discontinuation. Studies published in the British Journal of Psychiatry have shown that continued SSRI treatment significantly reduces the risk of relapse in both depression and OCD.

Missed Dose

If you forget to take a dose, wait until your next scheduled dose. Do not take a double dose to make up for a missed one. If you have any concerns, consult your doctor or pharmacist.

Overdose

What Are the Side Effects of Fevarin?

As with all medications, Fevarin can cause side effects, although not everyone experiences them. Many side effects are dose-related and tend to be most prominent during the first 1–2 weeks of treatment, often improving as the body adjusts to the medication. Nausea is particularly common at the start of treatment but usually resolves if you continue taking the tablets as prescribed.

Serious Side Effects Requiring Immediate Medical Attention

Sexual Dysfunction

SSRIs including fluvoxamine can cause sexual dysfunction, including decreased libido, erectile dysfunction, delayed ejaculation, and anorgasmia. These effects are relatively common but are often underreported by patients. In some cases, sexual side effects may persist even after discontinuation of the medication. This should be discussed openly with your healthcare provider, who may consider dose adjustment, switching to a different antidepressant, or adding adjunctive therapy.

Withdrawal Symptoms

Abruptly stopping Fevarin can cause withdrawal (discontinuation) symptoms, including anxiety, agitation, confusion, diarrhoea, insomnia, vivid dreams, dizziness, emotional instability, headache, irritability, nausea, vomiting, palpitations, sensory disturbances (tingling, electric shock sensations), visual disturbances, sweating, and tremor. These symptoms are covered in detail in the section on stopping treatment.

How Should You Stop Taking Fevarin?

Discontinuing Fevarin should always be done under medical supervision with a gradual dose reduction. Abruptly stopping the medication can trigger unpleasant and sometimes distressing withdrawal symptoms (also called discontinuation syndrome). These symptoms are a well-recognised effect of SSRI discontinuation and are not a sign of addiction.

Common withdrawal symptoms include:

• Anxiety, agitation, and restlessness
• Confusion and difficulty concentrating
• Diarrhoea, nausea, and vomiting
• Insomnia and vivid or disturbing dreams
• Dizziness and light-headedness
• Emotional instability (mood swings, irritability, tearfulness)
• Headache
• Palpitations
• Sensory disturbances (tingling, numbness, “brain zaps”)
• Visual disturbances
• Sweating and tremor

Your doctor will typically reduce the dose over a period of several weeks or months. Most people find that withdrawal symptoms are mild and resolve within two weeks. However, some individuals may experience more prolonged or severe symptoms, particularly after long-term treatment or high doses. If you experience significant withdrawal symptoms, your doctor may suggest slowing the taper further or temporarily increasing the dose before resuming a more gradual reduction.

How Should You Store Fevarin?

Proper storage ensures that the medication remains effective and safe throughout its shelf life. Follow these storage guidelines:

• Store at a temperature not exceeding 25°C (77°F).
• Keep in the original blister packaging to protect from moisture and light.
• Store out of the sight and reach of children.
• Do not use Fevarin after the expiry date printed on the carton and blister after “EXP”. The expiry date refers to the last day of that month.
• If your doctor ends your treatment, return any unused tablets to a pharmacy for safe disposal.
• Do not dispose of medications in household waste or down the drain. Ask your pharmacist about proper medication disposal to help protect the environment.

What Does Fevarin Contain?

Active Ingredient

Each tablet contains fluvoxamine maleate in a strength of 50 mg or 100 mg.

Inactive Ingredients (Excipients)

The other ingredients are: mannitol (E421), maize starch, pregelatinised starch, sodium stearyl fumarate, colloidal anhydrous silica, hypromellose, macrogol 6000, talc, and titanium dioxide (E171).

Tablet Appearance

• Fevarin 50 mg: Round, biconvex, scored, white to off-white film-coated tablet embossed with ‘291’ on both sides of the score line.
• Fevarin 100 mg: Oval, biconvex, scored, white to off-white film-coated tablet embossed with ‘313’ on both sides of the score line.

Sodium Content

This medicine contains less than 1 mmol (23 mg) sodium per tablet, meaning it is essentially sodium-free. This is relevant for patients on a sodium-restricted diet.

International Brand Names

Fluvoxamine is marketed under different brand names in various countries. The table below lists the most common brand names within the European Economic Area and other major markets: