Tolvaptan: uses and side effects

Description

Tolvaptan, a non-peptide orally active VRA, is in a class of medications called vasopressin V2 receptor antagonists. The empirical formula is C26H25ClN2O3. Molecular weight is 448.94. Tolvaptan is (±)-4’- ([7-chloro-2,3,45-tetrahydro -5-hydroxy-1H-1-benzazepin-1-yl] carbonyl)-otolu-m-toluidide. It is used to slow the worsening of kidney function in certain patients with autosomal dominant polycystic kidney disease (ADPKD, a certain type of inherited kidney disease).

Uses

This medication is used by people with a specific inherited kidney problem (autosomal dominant polycystic kidney disease-ADPKD). This inherited kidney problem leads to the growth of fluid-filled sacs (cysts) in your kidneys. Over time, the cysts grow in size, which can damage the way your kidneys work and lead to kidney failure. Tolvaptan belongs to a class of drugs known as vasopressin receptor antagonists. It works by slowing the growth of kidney cysts caused by ADPKD. This effect helps protect kidneys from damage and failure^[1]. The drug can be used in many clinical situations resulting in hyponatremia, including congestive heart failure, cirrhosis, and syndrome of inappropriate ADH secretion (SIADH), including SIADH related to malignancies.

Mechanism of Action

Tolvaptan binds to the V2 receptor with a 1.8 times greater affinity than ADH. The drug is a selective V2 receptor antagonist and shows 30 times more avidity for V2 receptors than V1 receptors. It works by increasing the amount of water released from the body as urine and decreasing cysts' growth in the kidneys. Removing fluid from the body and slowing the growth of cysts helps slow kidney function's worsening ^[2]. Tolvaptan antagonizes the effect of ADH, which results in the excretion of water-aquaresis without any effect on sodium and potassium excretion, which is in contrast to traditional diuretics. The drug is highly plasma protein bound (99%). About 40% of tolvaptan is bioavailable; the terminal half-life is about 12 hours.

Side effects^[3]

Tolvaptan (Jynarque) may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

thirst

dry mouth

frequent, excessive urination

heartburn

decreased appetite

Some side effects can be serious. If you experience any of these symptoms or those listed in the IMPORTANT WARNING section, call your doctor immediately:

diarrhea

inability to drink normally

dizziness

faintness

decreased urination

weakness

drowsiness

confusion

weight loss

rapid or pounding heartbeats

swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs

hoarseness

hives

References

[1] https://medlineplus.gov/druginfo/meds/a620041.html

[2]Bharath Rangarajan“Tolvaptan.” South Asian J Cancer 3 3 (2014): 182–184.

[3] https://www.webmd.com/drugs/2/drug-152441/tolvaptan-oral/details