Viibryd vs Prozac

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For patients suffering from major depressive disorder (MDD) or other forms of depression, certain medications that modify the balance of substances in the brain related to mood, known as neurotransmitters, can help stabilize emotional lows and manage symptoms. Viibryd and Prozac are two such drugs often prescribed for depression. Each interacts with different neurotransmitters in the brain, but both have effects on mood stabilization in patients struggling with depression. Prozac is a selective serotonin reuptake inhibitor (SSRI), which influences levels of serotonin. Viibryd, however, has a unique dual mechanism - it is both an SSRI and a partial agonist at one particular type of serotonin receptor called 5-HT1A; this may provide added benefits beyond what traditional SSRIs offer.

What is Viibryd?

Vilazodone (the generic name for Viibryd) is a newer class of antidepressant medication that combines the action of selective serotonin reuptake inhibitors (SSRIs), like Prozac, with partial serotonergic receptor agonist activity. Vilazodone was first approved by the FDA in 2011. Similar to Prozac, Viibryd increases levels of free serotonin by preventing it from being reabsorbed back into nerve cells, effectively keeping it available in the brain longer than usual. However, unlike Prozac which primarily affects serotonin and very little on other neurotransmitters like dopamine or norepinephrine, Viibryd also acts as a partial agonist at one subset of the serotonin receptors which can potentially offer additional therapeutic benefit and may lead to fewer side effects associated with SSRIs such as sexual dysfunction. Both are prescribed for major depressive disorder but their specific mechanisms differ slightly.

What conditions is Viibryd approved to treat?

Viibryd is approved for the treatment of several forms of depression:

  • Major depressive disorder (MDD)
  • Treatment-resistant depression, when used in combination with other antidepressants
  • Anxiety disorders that often coexist with depression.

How does Viibryd help with these illnesses?

Viibryd, similar to Prozac, also helps manage depression by increasing the amount of serotonin available in the brain's synapses. It does this through a dual mechanism - not only blocking reabsorption by neurons like Prozac but also directly stimulating certain serotonin receptors. The direct stimulation of these specific receptors may enhance and accelerate its antidepressant effect. Serotonin is a crucial neurotransmitter involved in mood regulation, cognition, memory, sleep patterns, hunger and body temperature among other things. Lower levels of serotonin are often associated with individuals suffering from depression hence increasing it can help limit depressive symptoms while stabilizing mood. Therefore Viibryd might offer some advantages over traditional SSRIs like Prozac particularly for those patients who have not responded adequately to them or cannot tolerate their side effects.

What is Prozac?

Prozac is a brand name for fluoxetine, which is a selective serotonin reuptake inhibitor (SSRI), meaning it increases the levels of serotonin in the brain by reducing its absorption. It does not have any significant effect on norepinephrine or dopamine reabsorption. Fluoxetine was one of the first SSRIs to be approved by the FDA in 1987 and has since been widely prescribed. As Prozac is an SSRI antidepressant, unlike Viibryd, it doesn't act as a partial serotonin receptor agonist. This means that its side-effect profile can be different from that of drugs like Viibryd - particularly with regard to causing less gastrointestinal upset but potentially more sexual dysfunction and weight gain (common side effects associated with many SSRIs). The predominant action on serotonin makes Prozac effective for treating depression and anxiety disorders, especially given its long half-life which allows once-daily dosing.

What conditions is Prozac approved to treat?

Prozac has been approved by the FDA for an extensive range of conditions including:

  • Major depressive disorder (MDD)
  • Obsessive-compulsive disorder (OCD)
  • Bulimia nervosa
  • Panic disorder, which may or may not be accompanied by agoraphobia It is also utilized in treating premenstrual dysphoric disorder (PMDD).

How does Prozac help with these illnesses?

Serotonin, a neurotransmitter crucial for mood regulation, plays key roles in many processes in the body. It influences not only mental wellness but also sleep cycles, appetite and even pain management. Low levels of serotonin have been associated with depression. Prozac works by increasing the availability of serotonin in the brain's synaptic space, thereby easing some symptoms of depression. Its action is primarily on serotonergic systems although it may impact other neurotransmitters as well to a lesser degree. As one of the most prescribed SSRI (Selective Serotonin Reuptake Inhibitors) antidepressants like Viibryd, Prozac has been fundamental for patients suffering from depressive disorders. Unlike Viibryd which combines both SSRI properties and partial serotonin receptor agonism, Prozac functions purely as an SSRI and thus may be chosen when monoaminergic transmission needs to be selectively modulated or combined with other treatments.

How effective are both Viibryd and Prozac?

Both vilazodone (Viibryd) and fluoxetine (Prozac) are commonly used in the treatment of depression, although they were approved by the FDA decades apart. Vilazodone was only recently approved for clinical use in 2011, while fluoxetine has been available since 1987. The two medications work on similar neurotransmitters but have distinct mechanisms of action; vilazodone is a selective serotonin reuptake inhibitor (SSRI) and a partial agonist at serotonergic 5-HT1A receptors, whereas fluoxetine is an SSRI that also affects norepinephrine and dopamine to some extent.

In terms of efficacy, both drugs appear to be effective in managing symptoms of major depressive disorder. A review published in 2015 found that vilazodone had comparable efficacy to other SSRIs such as fluoxetine. However, this study noted that there's currently less evidence available regarding the long-term effectiveness and safety profile for vilazodone compared to older medications like fluoxetine due its relatively recent introduction.

One potential advantage associated with Viibryd over Prozac relates to sexual side effects — which are common among many antidepressants — including decreased libido or difficulty achieving orgasm. Because it acts partially as an agonist at one subtype of serotonin receptor (the 5-HT1A receptor), Viibryd may cause fewer sexual side effects than other SSRIs like Prozac.

As always when choosing between different medications however, individual patient factors must be taken into account; including any concurrent medical conditions or medications being taken, patient preference regarding potential side-effects and response history to prior treatments.

abstract image of a researcher studying a bottle of drug.

At what dose is Viibryd typically prescribed?

Oral dosages of Viibryd typically start at 10 mg/day for the initial seven days, then increase to 20 mg/day. As treatment progresses, if necessary and under a healthcare provider's direction, the dosage may be increased further to 40 mg/day. However, studies have suggested that most adults with major depressive disorder respond effectively to the standard dose of 20 mg/day. Starting doses for adolescents are determined on an individual basis by their healthcare provider based on factors like age and overall health condition. It's important not to exceed the maximum recommended daily dose of 40 mg without direct medical advice.

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At what dose is Prozac typically prescribed?

Prozac therapy typically begins with a dosage of 20 mg/day taken orally in the morning. If necessary, the dose can be gradually increased after several weeks to a maximum of 80 mg/day. The increase should be made slowly, usually in increments of 20 mg at intervals no shorter than one week. For those who require higher dosages, multiple doses can be given throughout the day spaced evenly apart; however, it is crucial not to exceed the prescribed maximum daily limit for safety reasons. As always, any adjustments should only be made under your doctor's advice and supervision based on your response to treatment.

What are the most common side effects for Viibryd?

When comparing Viibryd to Prozac, some of the common side effects include:

  • Diarrhea
  • Nausea
  • Vomiting
  • Dry mouth
  • Sleep problems (insomnia)
  • Dizziness or feeling lightheaded
  • Excessive sweating
  • Abnormal dreams
  • Decreased sexual desire or ability, including abnormal ejaculation and impotence
  • Unusual changes in weight or appetite
    Please note that this is not an exhaustive list. Always consult with your doctor about potential side effects before starting a new medication.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Viibryd?

Viibryd, like Prozac, can also have serious side effects in rare cases. These include:

  • Increased risk of suicidal thoughts or tendencies, particularly in people under the age of 25
  • Allergic reactions such as hives, trouble breathing and swelling in your face or throat
  • Changes in vision including blurred vision, eye redness or swelling
  • Rapid heartbeat or palpitations; shortness of breath; feelings of dizziness especially on standing up indicating a drop-in blood pressure
  • Symptoms indicative of low sodium levels: headaches, difficulty concentrating, memory changes, unstable gait and weakness
  • Severe nervous system response manifesting as high fever; rigid muscles; confusion; fast heart rate and tremors. This is not common but could be a sign of neuroleptic malignant syndrome which needs immediate attention.

In addition to these symptoms you should watch out for signs that might suggest serotonin syndrome if you are taking other medications along with Viibryd: restlessness/agitation; hallucinations/delusions (seeing things that aren't there); rapid heart rate/tachycardia; muscle stiffness/rigidity/clonus (muscle spasms); coordination problems/ataxia (unsteady walk), nausea/vomiting/diarrhea.

If any such issues arise after starting Viibryd therapy contact your healthcare provider immediately.

What are the most common side effects for Prozac?

Common side effects of Prozac can include:

  • Dry mouth, sore throat
  • Sweating excessively
  • Feeling nervous or anxious
  • Upset stomach, nausea, vomiting, and loss of appetite
  • Weight changes (loss or gain)
  • Sleep issues like insomnia
  • Dizziness or feeling lightheaded
  • Frequent urination
  • Mild rash

Are there any potential serious side effects for Prozac?

While Prozac is generally well-tolerated, it can occasionally cause serious side effects. If you experience any of the following symptoms while taking Prozac, seek immediate medical attention:

  • Severe allergic reactions characterized by itching, hives, fever, swollen glands
  • Difficulty breathing or swelling in your face or throat
  • Sore throat with burning eyes and skin pain accompanied by red or purple skin rash that blisters and peels
  • Increased thoughts about suicide or self-harm
  • Occurrence of seizures (convulsions)
  • Unusual changes in mood or behavior that may include confusion
  • Vision disturbances such as blurred vision, tunnel vision, eye pain/swelling or seeing halos around lights
  • Fast/irregular heartbeats Finally, -Signs of a manic episode like racing thoughts, increased energy levels leading to reckless behaviour; feeling extremely happy one moment then irritable soon after; talking more than usual and facing severe problems with sleep.

Contraindications for Viibryd and Prozac?

Both Viibryd and Prozac, like most other antidepressant medications, may worsen symptoms of depression in some individuals. If you notice your depression worsening, or an increase in suicidal ideation, thoughts, or behavior while taking these drugs, please seek immediate medical attention.

Neither Viibryd nor Prozac should be taken if you are currently using or have recently stopped using monoamine oxidase (MAO) inhibitors. It is crucial to inform your physician about all the medications you're currently on; MAOIs require a washout period of about 5 weeks to clear from the system to prevent dangerous interactions with both Prozac and Viibryd.

How much do Viibryd and Prozac cost?

For the brand name versions of these drugs:

  • The price of 30 tablets of Viibryd (20 mg) averages around $350, which works out to approximately $11.67/day.
  • The price for 30 capsules of Prozac (20 mg) is about $570, or roughly $19/day.

Thus, if you are taking a standard dosage for both medications, then brand-name Viibryd is less expensive on a per-day treatment basis than Prozac. However, cost should not be your primary consideration in determining which of these drugs is right for you.

When looking at generic versions:

  • There currently isn't a generic version available for Viibryd as it's still under patent protection.
  • Fluoxetine (generic form of Prozac), however, can cost significantly less and varies based on pack size: from as low as $0.05/day when purchasing larger packs up front and not exceeding about $0.90/day depending on the quantity purchased and daily dosage required.

Please consult with your healthcare provider before deciding between two different medications; every person responds differently to medication due to factors like age, health status etc., so what works best will vary from person to person.

Popularity of Viibryd and Prozac

Vilazodone, also known by its brand name Viibryd, was prescribed to about 1.2 million people in the United States in 2020. As a selective serotonin reuptake inhibitor (SSRI) and partial serotonin receptor agonist, vilazodone represents a relatively new class of antidepressant medications that have been developed since the introduction of SSRIs like fluoxetine. It accounts for approximately 2% of all SSRI prescriptions given out within the US.

Fluoxetine, commonly known as Prozac among other names, was prescribed to around 4.7 million individuals in the USA during the same year. Fluoxetine is responsible for just under 20% of SSRI prescriptions and nearly 10% of overall antidepressant medication prescriptions within this country. The frequency with which fluoxetine has been prescribed over the past decade has remained largely stable.


Both Viibryd (vilazodone) and Prozac (fluoxetine) are widely used in the treatment of depression, with extensive clinical studies indicating their effectiveness over placebo. While both drugs can be used independently, combining them requires careful medical consideration due to potential interactions. Each operates differently: Prozac primarily affects serotonin and norepinephrine, while Viibryd has a unique mechanism of action as a selective serotonin reuptake inhibitor (SSRI) and partial 5HT1A receptor agonist.

Prozac is often chosen as a first-line option for treating depression, whereas Viibryd may be considered when patients haven't responded well to initial SSRI treatment or when they want to avoid certain side effects associated with SSRIs like Prozac - particularly sexual dysfunction.

Viibryd and Prozac are available in generic form which offers considerable cost savings especially for those paying out-of-pocket. As with most antidepressants, an adjustment period may be necessary before noticing significant changes from both medications.

In terms of side effects profile, both drugs share common ones such as nausea and sleep disturbances but Viibryd is less likely than many other antidepressants to cause sexual problems. It's crucial that patients stay vigilant about their mood during the initiation phase of either drug therapy; if depressive symptoms worsen or they experience suicidal thoughts or intentions towards self-harm they must seek medical help immediately.