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 tolvaptan |
| Samsca |
Pharmaceutical
company:
Otsuka Pharmaceutical Company, Ltd.
www.samsca.com |
Pharmacologic classification: selective vasopressin receptor antagonist
Therapeutic classification: hyponatremic drug
Pregnancy risk category: C
AVAILABLE FORMS
Tablets: 15 mg, 30 mg
INDICATIONS AND DOSAGES
Hypervolemic and euvolemic hyponatremia (serum sodium less than 125 mEq/L or symptomatic hyponatremia) in hospitalized patients, including those with heart failure, cirrhosis, and SIADH—
Adults: Initially, 15 mg P.O daily. May increase at 24-hour intervals to a maximum dose of 60 mg P.O. daily.
CONTRAINDICATIONS AND CAUTIONS
Contraindicated in patients with hypovolemic hyponatremia, in those who require an urgent rise in serum sodium level, and in those who are unable to sense or appropriately respond to thirst.
Contraindicated in patients who are anuric and in those receiving strong CYP3A inhibitors, such as ketoconazole, clarithromycin, itraconazole, telithromycin, saquinavir, nelfinavir, ritonavir, and nefazodone.
Use cautiously in patients with cirrhosis and dehydration and in those receiving hypertonic saline solution.
INTERACTIONS
Drug-drug.
CYP3A inducers (rifampin, rifabutin, rifapentine, barbiturates, phenytoin, carbamazepine): May decrease tolvaptan levels. Avoid using together.
Moderate CYP3A inhibitors (erythromycin, fluconazole, aprepitant, diltiazem, verapamil): May increase tolvaptan levels. Avoid using together.
Strong CYP3A inhibitors (ketoconazole, clarithromycin, itraconazole, telithromycin, saquinavir, nelfinavir, ritonavir, nefazodone): May increase tolvaptan levels. Use together is contraindicated.
Digoxin: May increase digoxin levels. Monitor patient and adjust digoxin dose, as needed.
P-glycoprotein inhibitors (cyclosporine): May increase drug levels. Reduce tolvaptan dose.
Drug-herb.
St John's wort: May decrease drug levels. Discourage use together.
Drug-food.
Grapefruit juice: Increases drug levels. Discourage use together.
ADVERSE REACTIONS
CNS: asthenia, fever, stroke.
CV: intracardiac thrombus, pulmonary embolism, ventricular fibrillation.
EENT: dry mouth, thirst.
GI: anorexia, constipation, nausea.
GU: polyuria, pollakiuria, urethral hemorrhage, vaginal hemorrhage.
Hematologic: disseminated intravascular coagulation.
Metabolic: hyperglycemia, diabetic ketoacidosis.
Musculoskeletal: rhabdomyolysis.
Respiratory: respiratory failure.
Other: deep vein thrombosis.
Reactions may be common, uncommon, life-threatening,
or COMMON AND LIFE-THREATENING.
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