Is Fluvoxamine similar to Fluoxetine? (+3 differences)

In this article, we will discuss whether Fluvoxamine and Fluoxetine are similar or not. We will dig deep into their mechanisms and common side effects to figure out the minor and major differences between the two drugs. 

Is Fluvoxamine similar to Fluoxetine?

Fluvoxamine may be similar to Fluoxetine. Both drugs belong to selective serotonin reuptake inhibitor (SSRI) antidepressants. These medications have a slight difference in their mechanism of action and therapeutic efficacy. 

Fluvoxamine (Luvox) and Fluoxetine (Prozac) are different drugs that belong to the same medication class but possess differences in their pharmacokinetics and side effects profile. 

It is important to note that different patients may respond differently to these medications. Therefore, always consult with a doctor to start the appropriate medication tailored to your specific needs and condition. 

What is the effectiveness rate of Fluvoxamine and Fluoxetine?

Comparing the efficacy and safety of Fluvoxamine and Fluoxetine based on research studies, it can be stated that there are no major differences observed in patients with major depressive disorder (1). 

A randomized study of 184 patients who were given Fluovoxamine (100mg/day) and Fluoxetine (20mg/day). Conducting results after 6 weeks of treatment, there were no significant changes found under the curve of change in the Hamilton depression rating scale (HAMD) total score (1). 

 However, it was observed in the HAMD scale that after 2 weeks of treatment in patients, Fluvoxamine showed significant improvement in the sleep cycle of patients. The efficacy and safety of both drugs were declared similar for major depressive disorder (MDD) patients (1). 

Whereas, comparing the side effects profile of both the drugs, it was observed that Fluvoxamine was associated with more adverse effects than Fluoxetine. Nausea vomiting is a common occurrence in the side effects profile of both drugs (2). 

What are the differences between Fluvoxamine and Fluoxetine? 

Some of the differences in the mechanism of action, therapeutic uses, and side effects profile of Fluvoxamine and Fluoxetine are discussed below:

Mechanism of action 

Fluvoxamine and Fluoxetine are both SSRI antidepressants and exert their actions by inhibiting the reuptake of serotonin into presynaptic serotonin neurons in the brain (3,4). 

Fluvoxamine has a slight effect on dopamine and norepinephrine uptake systems as well. Fluvoxamine has shown greater affinity with sigma-1 receptors which are involved in psychosis and aggression. Fluvoxamine has shown greater affinity for sigma-1 receptors as compared to other SSRIs (3). 

On the other hand, Fluoxetine has shown limited activity for nonadrenergic (norepinephrine) neurotransmitter reuptake. Fluoxetine has shown mild activity for the reuptake of serotonin (4). 

Therapeutic efficacy

Fluvoxamine has shown its therapeutic efficacy in several conditions such as (1,3):

• Obsessive-compulsive disorder (OCD)- Fluvoxamine is the most widely used SSRI in this domain. OCD is most commonly treated with Fluvoxamine. Many other obsessive-compulsive behaviours are also treated with Fluoxamine (3). 

Binge-eating disorders, bulimia nervosa, pathological gambling, compulsive buying, and autism patients have shown tremendous results when treated with Fluvoxamine (3).

• Panic Disorder- Patients displaying recurrent panic attacks were treated with Fluvoxamine. This medication reduced the number of panic attacks and anxiety in such patients (3).

However, it was also observed that Fluvoxamine showed impressive results in reducing panic attacks in patients with severe panic disorder as compared to Imipramine (3). 

• Post-traumatic stress disorder (PTSD)- Fluvoxamine when administered to patients with PTSD, resulted in great improvement. Fluvoxamine tends to improve sleep disturbances and hyperarousal symptoms in PTSD patients (3). 

• Major depressive disorder (MDD)-  Fluvoxamine has shown therapeutic efficacy in treating MDD in patients. This is a well-tolerated, safe, and efficacious drug for the treatment of MDD (1).   

Based on the efficacy of Fluoxetine, the following conditions are usually treated with this drug:

• Obsessive-compulsive disorder (OCD)- Belonging to the same therapeutic drug class as Fluvoxamine, it has been observed that Fluoxetine is also effective in the treatment of OCD. 

Fluoxetine can be used as a monotherapy or in combination with other medications to treat and alleviate the symptoms of OCD. Fluoxetine has shown better efficiency and safety for the treatment of OCD. 

• Major depressive disorder (MDD)- Similar to Fluvoxamine, Fluoxetine has also been used in treating MDD. This drug has also shown improvement in patients regarding sleep disturbances associated with MDD. Fluoxetine is also considered a well-tolerated and safe drug for treating MDD (1).  

Side effects 

The side effects associated with Fluvoxamine include (5):

• Drowsiness
• Dry mouth 
• Nausea
• Vomiting
• Constipation
• Indigestion
• Stuffy nose
• Sleeping difficulties
• Weightloss
• Nervousness
• Sexual problems in males and females

Common side effects related to Fluoxetine include (6):

• Anxiety 
• Heartburn
• Insomnia
• Yawning
• Weakness
• Diarrhea
• Loss of appetite
• Unusual dreams
• Excessive sweating
• Sexual problems in males and females

However, these side effects may vary from person to person and affect each patient varyingly. Depending on the medication dosage, frequency, body response, and metabolism, patients may show different side effects. 

Do not abruptly stop taking these medications due to the side effects as these may cause withdrawal symptoms. Therefore, always consult your doctor regarding any side effects that you observe while taking either Fluvoxamine, Fluoxetine, or both. 

Can you take Fluvoxamine and Fluoxetine together?

Fluvoxamine and Fluoxetine belong to the same drug class and possess the same mechanism of action. Combining them would result in a synergistic effect. However, combining such drugs should always be done under a doctor’s supervision.

Taking Fluoxamine and Fluoxetine in combination can help in treating the condition by exerting additional effects. This combination can also result in excessive serotonin surge due to the combined activity of both drugs.

Combining these medications can be safe but needs guidance and monitoring from a healthcare practitioner. There are chances to develop serotonin syndrome due to excessive serotonin reuptake in the brain (7). 

Serotonin syndrome is a life-threatening condition characterized by hallucinations, blurred vision, fever, excessive sweating, tremors, stiffness, shaking, tremors, nausea, and vomiting. If you exhibit these symptoms after taking a combined treatment of Fluvoxamine and Fluoxetine, immediately seek medical help (7). 

Conclusion

In the above article, we have successfully discussed the common similarities and differences between Fluvoxamine and Fluoxetine. These are two different drugs belonging to the same medication class with differences in mechanism of action, pharmacokinetics, therapeutic effects, and side effects. 

I would advise you to always start Fluoxamine or Fluoxetine or both with proper consultation with your doctor and always follow the guidelines and prescription given by your healthcare provider to ensure safe and efficacious use of either drug. 

References