Fluvoxamine is a selective serotonin reuptake inhibitor (SSRI) that primarily treats Obsessive-Compulsive Disorder (OCD) in adults and children 8 and older. In clinical use since 1983, it modulates brain chemistry to help manage the intrusive thoughts and repetitive behaviors associated with OCD.
How Fluvoxamine Addresses OCD Symptoms
Fluvoxamine treats OCD symptoms by influencing the neurotransmitter serotonin in the brain. Serotonin plays a role in regulating various bodily functions, including mood, anxiety levels, and thought processes. In individuals with OCD, there may be an imbalance or dysfunction in serotonin signaling pathways.
Fluvoxamine works by inhibiting the reuptake of serotonin into presynaptic neurons. Normally, serotonin is released and then reabsorbed by the neuron. By blocking this reabsorption, fluvoxamine increases the amount of serotonin available in the synaptic cleft. This increased serotonin enhances communication between brain cells, helping to alleviate the intrusive thoughts and compulsive behaviors of OCD. Fluvoxamine has a high affinity for the serotonin transporter (SERT), and at therapeutic doses, it also binds to sigma-1 receptors in the human brain, which may further contribute to its effects.
The Treatment Experience with Fluvoxamine
Treatment with fluvoxamine typically involves a gradual dose increase to help the body adjust and minimize initial side effects. For adults, a common starting dose is 50 mg at bedtime, increasing by 50 mg every 4 to 7 days. Children aged 8 to 17 often begin with 25 mg at bedtime, with similar gradual increases. The maximum daily dosage for adults is generally 300 mg, while for children aged 8 to 11, it is 200 mg, and for adolescents aged 12 to 17, it is 300 mg. Doses over 100 mg per day are often divided to help manage side effects.
While some initial physical improvements, such as in sleep or appetite, may appear within 1 to 2 weeks, full therapeutic benefits for OCD symptoms take longer. Significant reductions in obsessive thoughts and compulsive behaviors may become noticeable after 6 to 12 weeks of consistent treatment. If no improvement is observed after approximately 6 weeks at an adequate therapeutic dose, a healthcare provider may reconsider the treatment plan.
Common and Serious Side Effects
Fluvoxamine can cause various side effects, some common and mild, others less frequent but serious. Common side effects include nausea, drowsiness, dizziness, insomnia, headache, weakness, diarrhea, and dry mouth. These effects often lessen as the body adjusts. Other common effects include loss of appetite, increased sweating, nervousness, and sexual problems, which may not diminish over time.
More serious side effects require immediate medical attention. Fluvoxamine may increase the risk of suicidal thoughts or actions, particularly in children, teenagers, and young adults under 25, especially during the initial months of treatment or when dosage changes occur. Another serious concern is serotonin syndrome, a potentially life-threatening condition caused by excessive serotonin, with symptoms including agitation, hallucinations, confusion, rapid heartbeat, sweating, muscle stiffness, twitching, fever, and seizures. Other serious risks include abnormal bleeding or bruising, especially when taken with other blood-thinning medications, and seizures. Patients should also be monitored for low sodium levels (hyponatremia), which can cause headaches, confusion, or weakness.
Safe Use and Medication Management
Safe use of fluvoxamine involves careful consideration of drug interactions. It is important to inform a healthcare provider about all medications, including over-the-counter drugs, herbal products, and nutritional supplements. Fluvoxamine has a high potential for drug interactions because it affects various cytochrome P450 (CYP) enzymes, particularly being a strong inhibitor of CYP1A2 and CYP2C19.
Combining fluvoxamine with monoamine oxidase inhibitors (MAOIs) is contraindicated due to a significantly increased risk of serotonin syndrome. A washout period of at least 14 days is necessary when switching between these medications. Other serotonergic drugs, such as other SSRIs, SNRIs, triptans, certain pain medications like tramadol, and St. John’s wort, also increase the risk of serotonin syndrome. Fluvoxamine can also increase the levels of medications like warfarin, leading to a higher risk of bleeding, and certain benzodiazepines, potentially causing excessive sedation.
If a dose is missed, take it as soon as remembered. If it is almost time for the next dose, skip the missed one and resume the regular schedule. Do not double doses.
Fluvoxamine should never be stopped abruptly. Sudden discontinuation can lead to withdrawal symptoms, often called discontinuation syndrome. Symptoms can include dizziness, headaches, nausea, vomiting, irritability, agitation, sleep disturbances, and tingling skin. A healthcare provider will develop a supervised tapering plan to gradually reduce the dose over several weeks or months, which helps prevent these effects and allows for monitoring of any re-emerging OCD symptoms.