What You Should Know About Fluvoxamine XR Side Effects

Starting a new medication always comes with questions, and side effects are usually at the top of the list. If your doctor has prescribed Fluvoxamine XR (generic for Luvox CR) for OCD or social anxiety disorder, knowing what to expect can help you feel more prepared — and know when something needs medical attention.

This guide covers the most common side effects, the serious ones to watch for, and practical tips to manage them.

What Is Fluvoxamine XR?

Fluvoxamine XR is an extended-release capsule form of Fluvoxamine, a selective serotonin reuptake inhibitor (SSRI). It's FDA-approved to treat obsessive-compulsive disorder (OCD) and social anxiety disorder in adults. The extended-release formulation is taken once daily at bedtime, which can help reduce some side effects compared to the immediate-release version. For a deeper overview, see our guide on what Fluvoxamine XR is and how it works.

Common Side Effects

Most people who take Fluvoxamine XR will experience at least one side effect, especially during the first few weeks. These are generally mild and often improve as your body adjusts to the medication:

• Nausea — The most frequently reported side effect. Affects up to 34% of patients in clinical trials. Taking Fluvoxamine XR at bedtime and with food can help.
• Headache — Common in the first week or two. Over-the-counter pain relievers like Acetaminophen are usually safe to take (check with your pharmacist).
• Drowsiness and somnolence — Because Fluvoxamine XR is taken at bedtime, drowsiness is often less disruptive than with daytime medications.
• Insomnia — Some people experience difficulty sleeping despite taking it at bedtime.
• Dizziness — Usually mild. Avoid standing up too quickly.
• Diarrhea — Tends to resolve within the first week or two.
• Dry mouth — Staying hydrated and chewing sugar-free gum can help.
• Nervousness or anxiety — Paradoxically, some people feel more anxious in the first 1 to 2 weeks before the medication reaches its full effect.
• Weakness (asthenia) — Fatigue and general weakness are reported by some patients.
• Sweating — Increased perspiration is a common SSRI side effect.
• Decreased appetite — This may be temporary as your body adjusts.
• Tremor — Mild shaking, especially in the hands, can occur.
• Sexual side effects — Including abnormal ejaculation and decreased libido. This affects a meaningful percentage of patients and may not resolve on its own.
• Dyspepsia (upset stomach) — Taking Fluvoxamine XR with a small snack at bedtime may help.

Most of these side effects are dose-dependent — meaning they may be more noticeable when your doctor increases your dose from the starting 100 mg up to 200 mg or 300 mg.

Serious Side Effects

While rare, some side effects of Fluvoxamine XR are serious and require immediate medical attention:

Suicidal Thoughts and Behavior (Boxed Warning)

The FDA requires a boxed warning on all antidepressants, including Fluvoxamine XR. In clinical studies, antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults (ages 18 to 24). This risk is highest during the first few months of treatment and during dose changes.

Call your doctor or go to the emergency room immediately if you or someone you know experiences new or worsening suicidal thoughts, unusual changes in mood, or reckless behavior after starting Fluvoxamine XR.

Serotonin Syndrome

This is a potentially life-threatening condition caused by too much serotonin in the brain. It's most likely to happen when Fluvoxamine XR is combined with other serotonergic medications. Symptoms include:

• Agitation or restlessness
• Rapid heartbeat
• High blood pressure
• Muscle twitching or rigidity
• High fever
• Diarrhea

Serotonin syndrome is a medical emergency. For more on which medications to avoid, see our drug interactions guide.

Seizures

Fluvoxamine XR can lower the seizure threshold. If you have a history of seizures or epilepsy, make sure your doctor knows before you start treatment.

Abnormal Bleeding

SSRIs like Fluvoxamine XR can affect platelet function and increase the risk of bleeding, especially when combined with NSAIDs (like Ibuprofen or Naproxen), Aspirin, or blood thinners like Warfarin.

Hyponatremia (Low Sodium)

This is more common in elderly patients and those taking diuretics. Symptoms include headache, confusion, weakness, and in severe cases, seizures.

Angle-Closure Glaucoma

Fluvoxamine XR can trigger an episode of angle-closure glaucoma in people with certain eye anatomy. Seek immediate medical attention if you experience eye pain, vision changes, or swelling around the eyes.

Mania or Hypomania

In patients with bipolar disorder (sometimes undiagnosed), Fluvoxamine XR may trigger a manic episode. Symptoms include racing thoughts, decreased need for sleep, unusual energy, and risky behavior.

Specific Populations

Elderly Patients

Older adults may be more sensitive to side effects, especially drowsiness, dizziness, and hyponatremia. Doctors usually start with a lower dose and increase slowly.

Pregnancy and Breastfeeding

Fluvoxamine XR is a Pregnancy Category C medication. It should only be used during pregnancy if the potential benefit justifies the risk. Fluvoxamine does pass into breast milk, so breastfeeding mothers should discuss the risks and benefits with their doctor.

Young Adults (Under 25)

Because of the boxed warning about suicidal thoughts, young adults starting Fluvoxamine XR should be monitored closely, especially during the first few months and during dose changes.

Children

Fluvoxamine XR (the extended-release formulation) is not FDA-approved for children. The immediate-release version is approved for OCD in children ages 8 to 17.

How to Manage Side Effects

Here are some practical strategies to help minimize side effects:

• Take it at bedtime — Fluvoxamine XR is designed to be taken at night, which helps manage nausea and drowsiness.
• Start low, go slow — Your doctor will likely start you at 100 mg and increase gradually. Don't rush dose increases.
• Eat a small snack — Taking Fluvoxamine XR with food can reduce nausea and upset stomach.
• Limit caffeine — Fluvoxamine strongly inhibits the enzyme that breaks down caffeine (CYP1A2), which means caffeine can build up in your system to 5 times its normal level. Cut your coffee intake significantly or switch to decaf.
• Avoid alcohol — Alcohol adds to the sedative effects and can worsen depression and anxiety.
• Stay hydrated — Helps with dry mouth, headaches, and overall well-being.
• Be patient — Many side effects improve after 1 to 2 weeks. The full therapeutic effect of Fluvoxamine XR may take 4 to 8 weeks.
• Don't stop abruptly — Stopping Fluvoxamine XR suddenly can cause withdrawal symptoms (dizziness, nausea, irritability, "brain zaps"). Always taper under your doctor's guidance.

Final Thoughts

Side effects are a normal part of starting any SSRI, and Fluvoxamine XR is no exception. The good news is that most common side effects are mild and improve with time. The key is knowing which ones to watch for, managing them proactively, and staying in touch with your doctor — especially in the first few weeks.

If you're having trouble finding Fluvoxamine XR at your pharmacy due to the current shortage, Medfinder can help you locate pharmacies near you that have it in stock.