Tolvaptan 30 mg Tablets – Complete Guide for Hyponatremia & Polycystic Kidney Disease

🔹What is Tolvaptan 30 mg Used For?

Tolvaptan is an oral vasopressin receptor antagonist used primarily to treat:

1. Hyponatremia (low sodium levels) in:
   1. Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)
   1. Congestive heart failure
   1. Cirrhosis-related fluid retention
2. Autosomal Dominant Polycystic Kidney Disease (ADPKD)
   1. To slow kidney function decline and cyst growth

🔹How Tolvaptan Works

Tolvaptan selectively blocks vasopressin V2 receptors in the kidney. This:

• Promotes excretion of free water (aquaresis) without significant electrolyte loss
• Raises serum sodium levels in hyponatremia
• Reduces cyst formation and growth in ADPKD by decreasing cyclic AMP levels in kidney cells

🔹Indications and Dosage

🔸 1. Hyponatremia (Samsca®):

• Starting dose: 15 mg once daily
• Titrated up to: 30–60 mg/day based on response and serum sodium
• Tolvaptan 30 mg may be used after initial dose adjustment

🔸 2. Autosomal Dominant Polycystic Kidney Disease (Jinarc®):

• Initiation typically under specialist care
• Split dose regimen: e.g., 45 mg in the morning + 15 mg evening, titrated up to 90/30 mg (depending on tolerability)
• 30 mg tablets may be used as part of the titration schedule

⚠️ Always under medical supervision with liver monitoring.

🔹Benefits of Tolvaptan 30 mg

• Corrects low sodium effectively in hyponatremic states
• Improves neurologic symptoms of hyponatremia (e.g., confusion, seizures)
• In ADPKD: slows down kidney enlargement and renal function decline
• Oral administration with a once-daily dosing option (for hyponatremia)

🔹How to Take Tolvaptan 30 mg

• Take orally with or without food
• Administer early in the day to minimize nocturnal urination
• Maintain adequate fluid intake to avoid dehydration
• Avoid grapefruit juice, which increases drug levels

🔹Side Effects

✅ Common Side Effects:

• Increased thirst
• Frequent urination
• Dry mouth
• Constipation
• Weakness or fatigue
• Polyuria (increased urine output)

⚠️Serious Side Effects:

• Liver injury (monitor ALT, AST)
• Dehydration or hypotension
• Rapid correction of sodium (can cause osmotic demyelination syndrome)
• Hypernatremia
• Electrolyte imbalances

🔹Liver Monitoring Requirement

• Particularly important in ADPKD treatment
• Monitor liver enzymes (ALT, AST, bilirubin) at:
  • Baseline
  • Every month for the first 18 months
  • Then every 3 months
• Discontinue if signs of drug-induced liver injury appear

🔹Warnings and Precautions

• Do not use in patients who cannot perceive or respond to thirst
• Avoid in hypovolemic hyponatremia
• Use caution in patients with hepatic impairment
• Requires hospital initiation for hyponatremia due to risk of rapid correction
• Avoid in pregnancy and breastfeeding

🔹Drug Interactions

• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin) ↑ tolvaptan levels
• CYP3A4 inducers (e.g., rifampin, phenytoin) ↓ efficacy
• Diuretics or other nephrotoxic drugs may increase dehydration risk
• Avoid grapefruit products

🔹Storage Instructions

• Store at 20–25°C (68–77°F)
• Keep away from moisture and direct sunlight
• Keep out of reach of children
• Do not use past the expiration date

🔹Patient Tips

• Drink water as instructed to prevent dehydration
• Report any signs of liver trouble (e.g., yellowing of skin, dark urine)
• Do not take more or less than prescribed
• Inform your doctor about all other medications and supplements