Tolvaptan

SAMSCA

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Pronunciation: tol-VAP-tan

Tolvaptan ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Tolvaptan ballicule

What it isSelective V2 vasopressin antagonist; hyponatremia and autosomal dominant polycystic kidney disease.

Why this oneIt clears free water without sodium loss and slows kidney enlargement in polycystic disease.

What limits it⚑ Overrapid sodium correction can cause osmotic demyelination, requiring inpatient initiation; liver toxicity drives REMS monitoring in ADPKD.

Tolvaptan molecular structure (skeletal formula) — Molecular structure: Tolvaptan

Tolvaptan prescription history

Animated chart of estimated U.S. prescriptions per year, Diuretics (1953–2026). Tolvaptan enters in 2009 (estimated).

FDA-approved for

hyponatremia (2009)
ADPKD (2018)

Classes and tags

Clinical profile

Therapeutic safety burden4 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk1 / 4

Legacy pregnancy categoryUnknown / historical label unavailable

Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.

FDA label

Read the full label on DailyMed ↗

BOXED WARNING Initiate/re-initiate only in hospital with close serum sodium monitoring (too-rapid correction causes osmotic demyelination); not for ADPKD outside REMS due to hepatotoxicity.

FDA dosing	Population	Start	Target	Max
Hyponatremia (hypervolemic/euvolemic; HF, cirrhosis, SIADH)	Adult	15 mg QD	30 mg QD	60 mg QD

Titration >=24 hours between dose increases

Renal No adjustment needed (no data if CrCl <10)

Hepatic Avoid in underlying liver disease (exposure not clinically affected)

Limit to <=30 days; increase dose no sooner than every 24 h

Instructions

Initiate/re-initiate in a hospital; monitor serum sodium.
Do not treat for more than 30 days (liver injury risk).
Avoid fluid restriction during first 24 h; patient may drink to thirst.
Do not use with strong CYP3A inhibitors.

Available strengths

tab 15, 30, 45, 60, 90 mg

Contraindications

ADPKD outside of FDA-approved REMS
Unable to sense or respond to thirst
Hypovolemic hyponatremia
Concomitant strong CYP3A inhibitors
Anuria

Cautions

Too-rapid sodium correction causes osmotic demyelination
Liver injury - limit to 30 days, avoid in liver disease
Dehydration/hypovolemia
Avoid with hypertonic saline
Hyperkalemia
Urinary outflow obstruction

Adverse reactions

Thirst
Dry mouth
Asthenia
Constipation
Pollakiuria/polyuria
Hyperglycemia

Pregnancy Insufficient human data; animal embryo-fetal toxicity

Lactation Breastfeeding not recommended

Cost

Tolvaptan (SAMSCA)

What pharmacies pay · NADAC 9/30/26

Strength		#/mo	generic $/mo	CostPlus
15 mg	tab	30 qd	$437.22	offered
30 mg	tab	30 qd		offered
45 mg	tab	30 qd		not offered
60 mg	tab	30 qd		not offered
90 mg	tab	30 qd		not offered

Generic entry2026

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Self-check

What does tolvaptan remove without sodium loss?
Free water.
What neurologic injury can overrapid sodium correction cause?
Osmotic demyelination.