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Vilazodone is an antidepressant in a group of drugs called selective serotonin reuptake inhibitors (SSRIs). it is used to treat major depressive disorder (MDD). 

Abstract

Vilazodone is an antidepressant in a group of drugs called selective serotonin reuptake inhibitors (SSRIs).
[2]

Brand Names

Viibryd,
Viibryd Starter
[2]

Manufacturers

Trovis Pharma
[1]

History

Two pharmaceutical companies walked away from vilazodone’s development before it was licensed to Genaissance, which was later acquired by Clinical Data. Vilazodone was originally discovered by

Merck KGaA (the German Merck) and had licensed the technology to GlaxoSmithKline in 2001. Glaxo subsequently ran the drug through several clinical trials but hit a snag when the drug showed disappointing results in a Phase IIb study which caused the company to return the rights back to Merck.
[3]

Uses

Vilazodone is used to treat major depressive disorder (MDD).
[2]

Pharmacology

Vilazodone acts as a serotonin reuptake inhibitor (IC50 = 0.5 nM) and 5-HT1A receptor partial agonist (IC50 = 0.2 nM; IA = ~60-70%). It has negligible affinity for other serotonin receptors such as 5-HT1D, 5-HT2A, and 5-HT2C.

Partial agonism of the 5-HT1A receptor is a relatively novel mechanism of action and is also shared by the anxiolytic buspirone (Buspar), and the atypical antipsychotic / antidepressant aripiprazole.
[4]

Schedule

It is not a controlled substance in the US. 

Dosage

The dosage depends on the reason why it is prescribed for an individual. In general,
10 mg PO qDay for 7 days, then increase to 20 mg qDay for 7 days, then finally increase to 40 mg qDay for maintenance dose
Coadministration with strong CYP3A4 inhibitors (eg, ketoconazole): Not to exceed 20 mg PO qDay
Coadministration with moderate CYP3A4 inhibitors (eg, erythromycin): Reduce dose to 20 mg/day if intolerable adverse events emerge.
No dosage adjustment is recommended on the basis of age
[5] 

Drug Interactions

Contraindicated interactions with:

isocarboxazid
phenelzine
rasagiline
selegiline
selegiline transdermal
tranylcypromine

Serious interactions with:

almotriptan
amiodarone
amitriptyline
citalopram
clarithromycin
clomipramine
cocaine
diltiazem
doxepin
dronedarone
duloxetine
escitalopram
fluconazole
fluoxetine
lopinavir
lorcaserin
meperidine
methamphetamine
nortriptyline
octreotide
paroxetine

Significant interactions with:

aldesleukin
basiliximab
dasatinib
lurasidone
mifepristone
oxycodone
ranolazine
rifampin
tamoxifen
zafirlukast
[6]

Adverse Effects

Diarrhea (28%)
Nausea (23%)
Dizziness (9%)
Xerostomia (8%)
Insomnia (6%)
Vomiting (5%)
Fatigue (4%)
Abnormal dreams (4%)
Libido decreased (4%)
Abnormal orgasm (3%)
Dyspepsia (3%)
Flatulence (3%)
Gastroenteritis (3%)
Somnolence (3%)
Paresthesia (3%)
Arthralgia (3%)
Restlessness/akathisia (3%)
Jittery sensation (2%)
Tremor (2%)
Delayed ejaculation (2%)
Erectile dysfunction (2%)
Increased appetite (2%)
[7]

Contraindications

Hypersensitivity

MAO inhibitors: Do not administer concomitantly or within 14 days of MAO inhibitors because of serious and sometimes fatal drug interactions may occur with serotonergic drugs, with symptoms including tremor, myoclonus, diaphoresis, nausea, vomiting, flushing, dizziness, hyperthermia with features resembling neuroleptic malignant syndrome, seizures, rigidity, autonomic instability with possible rapid fluctuations of vital signs, and mental status changes that include extreme agitation progressing to delirium and coma.
[8]

Cautions

May cause serotonin syndrome or neuroleptic malignant syndrome-like reactions including agitation, hallucinations, coma, autonomic instability (eg, tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (eg, hyperreflexia, incoordination), and/or gastrointestinal symptoms (eg, nausea, vomiting, diarrhea)
Has not been systematically evaluated in patients with seizure disorders (caution advised)
Serotonin reuptake inhibition may increase risk of bleeding (caution with drugs that inhibit platelets or coagulation)
Decrease dose gradually when discontinuing to avoid dysphoric mood, irritability, insomnia, agitation, and confusion
CYP3A4 (major substrate); CYP2C19 (minor substrate, minor inhibitor, minor inducer); CYP2D6 (minor substrate, minor inhibitor); CYP2C8 (moderate inhibitor); increased plasma concentration (by 50%) observed when coadministered with strong CYP3A4 inhibitors (eg, ketoconazole)

Highly bound to plasma proteins (administration to patient taking another drug that is highly protein bound may increase free concentrations of the other drug)

Hyponatremia has been reported with other SSRIs, and SNRIs; common adverse effects include diarrhea, nausea, xerostomia, dizziness, and insomnia; can occur in association with syndrome of inappropriate antidiuretic hormone secretion.

Concomitant use with serotonin precursors (eg, tryptophan) not recommended

Serotonin reuptake inhibition may increase risk of bleeding (caution when coadministered with aspirin, NSAIDs, warfarin, and other anticoagulants)

Pregnancy: Conflicting evidence regarding use of SSRIs during pregnancy and increased risk of persistent pulmonary hypertension of the newborn.
[8]

Pricing

The pricing varies depending on what form one would like to buy, and the brand.
The 40mg tablet is priced at $4.91 to $5.40.
[1]

Referenecs

[1] http://www.drugs.com/history/viibryd.html
[2] http://www.drugs.com/mtm/vilazodone.html
[3] http://www.gekkowire.com/?p=6244&page=2
[4] http://www.sciencedirect.com/science/article/pii/S0014299905000415
[5] http://reference.medscape.com/drug/viibryd-vilazodone-999620#13
[6] http://reference.medscape.com/drug/viibryd-vilazodone-999620#3
[7] http://reference.medscape.com/drug/viibryd-vilazodone-999620#4
[8] http://reference.medscape.com/drug/viibryd-vilazodone-999620#5