Tolvaptan 15 mg Tablets – Complete Guide for Treating Hyponatremia & ADPKD

🔹What Is Tolvaptan 15 mg Used For?

Tolvaptan 15 mg is used in the treatment of:

1. Hyponatremia (low blood sodium levels)

Caused by:

• Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)
• Heart failure
• Liver cirrhosis

2. Autosomal Dominant Polycystic Kidney Disease (ADPKD)

To slow the progression of kidney cyst development and preserve kidney function.

🔹How Tolvaptan Works

Tolvaptan is a selective vasopressin V2 receptor antagonist. It works by:

• Blocking the action of vasopressin, a hormone that causes water retention
• Promoting aquaresis — excretion of free water without losing sodium or potassium
• In ADPKD, reducing cAMP signaling in renal cells, thus slowing cyst growth and kidney damage

🔹Dosage and Administration

🔸 For Hyponatremia (Samsca®):

• Starting dose: 15 mg once daily
• May be increased to 30 mg or 60 mg based on clinical response and sodium levels

🔸 For ADPKD (Jinarc®):

• Used as part of a split-dose regimen (e.g., 45/15 mg, 60/30 mg, 90/30 mg)
• 15 mg tablets are commonly used as the lower evening dose or for titration

Administration:

• Take orally once a day (or twice daily in split-dose)
• Can be taken with or without food
• Should be taken in the morning to reduce nighttime urination

🔹Benefits of Tolvaptan 15 mg

• Effectively raises serum sodium levels
• Improves symptoms of hyponatremia (e.g., confusion, lethargy)
• Slows the progression of ADPKD, delaying the need for dialysis
• Oral once-daily or split-dosing convenience

🔹Common Side Effects

🔹Serious Side Effects (Monitor Closely):

• Liver toxicity (increased AST, ALT, bilirubin)
• Rapid sodium correction (risk of osmotic demyelination)
• Hypernatremia
• Severe dehydration or low blood pressure

💡 Liver function tests are required regularly, especially in ADPKD patients.

🔹Warnings & Precautions

• Do not use in patients with an inability to perceive or respond to thirst
• Not recommended for hypovolemic hyponatremia
• Avoid in patients with liver disease unless essential
• Requires hospital initiation for hyponatremia due to risk of overcorrection
• Avoid use during pregnancy and lactation

🔹 Drug Interactions

🔹Liver Monitoring (Especially in ADPKD)

Tolvaptan can cause serious liver damage, particularly in long-term use for ADPKD. Monitoring protocol:

• Baseline liver tests before starting
• Monthly monitoring for first 18 months
• Then every 3 months thereafter
• Discontinue if signs of liver injury appear

🔹Storage Instructions

• Store at 20–25°C (68–77°F)
• Protect from moisture, heat, and direct sunlight
• Keep in original packaging and out of reach of children

🔹Patient Tips

• Stay hydrated but avoid overhydration — follow physician advice
• Monitor for signs of liver problems: yellowing skin, dark urine, abdominal pain
• Do not skip liver function tests if used for ADPKD
• Report any signs of overcorrection of sodium (e.g., seizures, confusion)