tolvaptan

Absorption: 40% absorbed following oral administration.

Distribution: Well distributed to tissues.

Protein Binding: >99%.

Metabolism/Excretion: Extensively metabolized in the liver via the CYP3A4 isoenzyme; 59% excreted in the feces (19% as unchanged drug), with 40% excreted in the urine (<1% as unchanged drug).

Half-Life: 12 hr.

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
PO	within 8 hr	2–4 hr‡	7 days

‡Plasma concentrations.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Hepatic impairment;
Urgent need to acutely raise serum sodium (Samsca);
Patients who cannot appropriately sense/respond to thirst;
Hypovolemia;
Uncorrected abnormal serum sodium concentrations (Jynarque);
Anuria;
Uncorrected urinary outflow obstruction;
Lactation: Lactation.

Use Cautiously in:

Severe malnutrition, alcoholism, or advanced liver disease (↑ risk of osmotic demyelination; correct electrolyte abnormalities at a slower rates);
Cirrhosis (↑ risk of GI bleeding; use only when the need to treat outweighs risk);
OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
Pedi: Safety and effectiveness not established in children;
Geri: Older adults may have ↑ sensitivity to effects.

Adv. Reactions/Side Effects ⬆ ⬇

CV: palpitations

Derm: dry skin, rash

Endo: hyperglycemia

F and E: thirst, hypernatremia, hypovolemia

GI: constipation, diarrhea, dry mouth, ↓appetite, dyspepsia, HEPATOTOXICITY

GU: polyuria

Metab: hyperuricemia

Neuro: dizziness, weakness, osmotic demyelination

Misc: HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS)

Interactions ⬆ ⬇

Drug-drug:

Strong CYP3A inhibitors, including ketoconazole, clarithromycin, itraconazole, nelfinavir, ritonavir, and nefazodone, as well as moderate CYP3A inhibitors, including erythromycin, fluconazole, aprepitant, diltiazem, and verapamil, may ↑ levels and risk of toxicity; avoid concurrent use.
CYP3A inducers, including rifampin, may ↓ levels and effectiveness; avoid concurrent use with Jynarque; dosage adjustments may be necessary with Samsca.
P-glycoprotein inhibitors, including cyclosporine, may ↑ levels and risk of toxicity; dosage adjustments may be necessary.
May ↑ risk of hyperkalemia with angiotensin II receptor blockers, ACE inhibitors, and potassium-sparing diuretics.
Diuretics may ↑ risk of too rapidly correcting serum sodium concentrations.
May inhibit effects of desmopressin; avoid concurrent use.

Drug-Food:

Grapefruit juice may ↑ levels and the risk of toxicity; avoid concurrent use.

Route/Dosage ⬆ ⬇

Samsca and Jynarque should not be used interchangeably.

Hyponatremia (Samsca)

PO (Adults ): 15 mg once daily initially; may ↑ at intervals of ≥1 day to 30 mg once daily, up to a maximum of 60 mg once daily. Do not use for longer than 30 days.

Autosomal Dominant Polycystic Kidney Disease (Jynarque and Jinarc)

PO (Adults ): 60 mg/day initially (taken as 45 mg upon wakening and then 15 mg 8 hr later); may be ↑ after at least 1 wk to 90 mg/day (taken as 60 mg upon wakening and then 30 mg 8 hr later); may then be ↑ after at least 1 wk to 120 mg/day (taken as 90 mg upon wakening and then 30 mg 8 hr later); Concurrent use of moderate CYP3A inhibitors: 30 mg/day initially (taken as 15 mg upon wakening and then 15 mg 8 hr later); may be ↑ after at least 1 wk to 45 mg/day (taken as 30 mg upon wakening and then 15 mg 8 hr later); may then be ↑ after at least 1 wk to 60 mg/day (taken as 45 mg upon wakening and then 15 mg 8 hr later).

Availability ⬆ ⬇

(Generic available)

Tablets (Jynarque): 15 mg; 30 mg; 45 mg; 60 mg; 90 mg
Tablets (Samsca): 15 mg; 30 mg

Assessment ⬆ ⬇

Samsca: Monitor neurologic status and assess for signs and symptoms of osmotic demyelination syndrome (trouble speaking, dysphagia, drowsiness, confusion, mood changes, involuntary movements, weakness, seizures), especially during initiation and after titration. If a rapid ↑ in sodium or symptoms occur, discontinue Samsca and consider administration of hypotonic fluid.
Jynarque: Monitor for signs and symptoms of liver injury (fatigue, anorexia, right upper abdominal discomfort, dark urine, jaundice) periodically during therapy. If symptoms occur, discontinue Jynarque.
Monitor fluid balance. If hypovolemia occurs interrupt or discontinue tolvaptan and provide supportive care (monitor vital signs, balance fluid and electrolytes).

Lab Test Considerations:

Monitor serum sodium frequently during initiation and dose titration and periodically during therapy. Too rapid correction of hyponatremia (>12 mEq/L/24 hr) can cause osmotic demyelination syndrome.
- Monitor serum potassium in patients with serum potassium >5 mEq/L or taking medication known to ↑ potassium.
- Jynarque: Monitor ALT, AST, and bilirubin 2 wk and 4 wk after starting therapy, then monthly for 1st 18 mo, and every 3 mo thereafter. If ALT, AST, or bilirubin ↑ to >2 times upper limit of normal (ULN), immediately discontinue Jynarque; repeat tests as soon as possible (within 48–72 hr). If levels stabilize or resolve, Jynarque may be reinitiated with ↑ frequency of monitoring as long as ALT and AST remain below 3 times ULN. Do not restart in patients with signs or symptoms of hepatic injury or whose ALT or AST is ever >3 times ULN during therapy with tolvaptan, unless another explanation for liver injury exists and the injury has resolved. In patients with a stable, low baseline AST or ALT, an ↑ >2 times baseline, even if <2 times ULN, may indicate early liver injury. Suspend and promptly (48–72 hr) reevaluate liver enzymes before reinitiating therapy with more frequent monitoring.

Implementation ⬆ ⬇

Initiate and reinitiate Samsca in a hospital where serum sodium can be closely monitored.
- REMS: REMS requirements are for Jynarque product.
- Avoid fluid restriction during first 24 hr of therapy.
PO: Administer once daily without regard to meals.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take tolvaptan as directed. Avoid drinking grapefruit juice during therapy; may cause ↑ levels. Take missed doses as soon as remembered, but not if just before next dose; do not double doses. Do not stop and restart therapy. Restarting therapy may require hospitalization.
REMS: Explain requirements of Tolvaptan for ADPKD Shared System REMS program (providers must be certified and inform patients of risk of hepatotoxicity; patient must enroll, comply with ongoing monitoring requirements, and get Jynarque from pharmacies participating in REMS program).
Inform patients they can continue fluid ingestion in response to thirst during therapy and should have water available to drink at all times during therapy. Following discontinuation of therapy, resume fluid restriction.
Advise patient to notify health care provider immediately if signs and symptoms of hepatotoxicity (feeling tired, fever, loss of appetite, rash, nausea, itching, right upper abdomen pain or tenderness, yellowing of skin and white part of eye, vomiting, dark urine) occur.
Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care provider before taking other medications.
Advise patient to notify health care provider if signs of dehydration (vomiting, diarrhea, inability to drink normally, dizziness, feeling faint) or bleeding (vomiting bright red blood, dark blood clots, or coffee-ground-like material; black, tarry stools; bloody stools).
Rep: Advise women of reproductive potential to notify health care provider if pregnancy is planned or suspected and to avoid breastfeeding.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇