Drug General Information (ID: DDIF4AZMYS)
Drug Name			Vasopressin		Drug Info		Valbenazine		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Vasoconstrictor Agents				Vmat2 Inhibitors
Structure

Mechanism of Vasopressin-Valbenazine Interaction (Severity Level: Moderate)
Additive CNS depression effects Click to Show/Hide Mechanism Graph
Drug Name		Vasopressin				Valbenazine
Mechanism 1		CNS depression effects				CNS depression effects
Key Mechanism Factor 1
		Factor Name		CNS depression effects
		Factor Description		CNS depressants are drugs that inhibit or suppress brain activity and can reduce mental and physical processes. Excessive CNS depression can lead to decreased heart rate, slow breathing (less than 10 breaths per minute), extreme confusion or loss of memory, nausea and vomiting, poor judgment, blue lips or fingertips, irritability and aggression, and clammy or cold skin.
Mechanism Description		Additive CNS depression effects by the combination of Vasopressin and Valbenazine
Increased risk of prolong QT interval Click to Show/Hide Mechanism Graph
Drug Name		Vasopressin				Valbenazine
Mechanism 2		Prolong QT interval				Prolong QT interval
Key Mechanism Factor 2
		Factor Name		QT interval
		Factor Description		Long QT syndrome is a heart signaling disorder that can cause a fast, chaotic heartbeat (arrhythmia). Many people may not exhibit symptoms, and usually the condition is detected during routine medical tests. In others, the most common symptoms include: sudden fainting, palpitations, dizziness, seizures, sudden death.
Mechanism Description		Increased risk of prolong QT interval by the combination of Vasopressin and Valbenazine

Recommended Action
Management		Caution and clinical monitoring are recommended if concomitant use of valbenazine with other drugs that can prolong the QT interval is required. Valbenazine is not recommended for use in patients with congenital long QT syndrome or with arrhythmias associated with a prolonged QT interval. In patients with other risk factors for QT prolongation, the QT interval should be assessed before increasing the dose of valbenazine. The manufacturer recommends that valbenazine dosage be reduced to 40 mg once daily in patients on concomitant therapy with a strong CYP450 3A4 inhibitor (e.g., itraconazole, ketoconazole, clarithromycin). Valbenazine dose reduction should also be considered in patients on concurrent therapy with a strong CYP450 2D6 inhibitor (e.g., paroxetine, fluoxetine, quinidine), or in patients who are poor metabolizers of CYP450 2D6.

References
1	Product Information. Ingrezza (valbenazine). Neurocrine Biosciences, Inc., San Diego, CA.