Vaprisol (conivaptan HCl/dextrose 5 % in water)

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Last reviewed · Source: First Databank (FDB) drug data

Overview

Conivaptan, a benzazepine derivative, is a nonpeptide antagonist of arginine vasopressin (antidiuretic hormone) V1A and V2 receptors.

Conivaptan, a benzazepine derivative, is a nonpeptide antagonist of arginine vasopressin (antidiuretic hormone) V1A and V2 receptors. Circulating concentrations of vasopressin, which usually are elevated in patients with euvolemic or hypervolemic hyponatremia, play an important role in the regulation of fluid and electrolyte balance. The activity of vasopressin at renal V2 receptors, which are functionally coupled to aquaporin channels in the apical membrane of the renal collecting ducts, helps maintain plasma osmolality within the normal range by increasing permeability of the renal collecting ducts to water.

Vasopressin also causes vasoconstriction through its actions on vascular V1A receptors. Conivaptan antagonizes the effects of vasopressin at V2 receptors, resulting in excretion of free water (or increased effective water clearance), which generally is accompanied by increased net fluid loss, increased urine output, and decreased urine osmolality. Blockade of vascular V1A receptors may cause splanchnic vasodilation, possibly resulting in hypotension or variceal bleeding in patients with cirrhosis (especially those with portal hypertension).

Conivaptan is extensively metabolized by cytochrome P-450 (CYP) isoenzyme 3A and also is a potent inhibitor of CYP3A. Following IV or oral administration, conivaptan exhibits nonlinear pharmacokinetics, probably secondary to the drug inhibiting its own metabolism. Several active metabolites have been identified, but their contribution to the drug's clinical effects probably is minimal since exposure to the metabolites combined is only about 7% that of the parent drug.

Following administration of an IV dose of 10 mg or an oral dose of 20 mg, about 83% of the dose was excreted in the feces and about 12% in the urine over several days. About 1% of the dose was excreted in urine as unchanged drug over the first 24 hours after IV administration.

Generic name: conivaptan HCl/dextrose 5 % in water

Reference product & biosimilars

No reference, biosimilar or interchangeable associated with this drug.

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Indications

The following indications are listed for Vaprisol:

  • Hyponatremia

Also known as: Decreased Serum Na, Decreased Serum Sodium, Low Serum Sodium.

Dosing

The recommended adult dosage of conivaptan hydrochloride for the treatment of euvolemic or hypervolemic hyponatremia is a loading dose of 20 mg infused IV over 30 minutes followed by continuous IV infusion of 20 mg over 24 hours; following the first day of treatment, conivaptan hydrochloride therapy should be continued for an additional 1-3 days at a dosage of 20 mg daily by continuous IV infusion. Vital signs, fluid status, and serum sodium concentration must be monitored carefully, and administration of the drug should be discontinued if hypotension or hypovolemia occurs or if serum sodium concentration increases at too rapid a rate (see Overly Rapid Correction of Serum Sodium Concentration and also see Hypovolemia and Hypotension under Cautions: Warnings/Precautions). If serum sodium concentration is not increasing at the desired rate, the dosage of conivaptan hydrochloride may be increased to 40 mg daily (the maximum recommended daily dosage (after the loading dose)) as a continuous IV infusion. In clinical trials of the drug, a dosage of 80 mg daily was not substantially more effective than 40 mg daily and was associated with a higher incidence of infusion site reactions and adverse effects requiring drug discontinuance. The total duration of conivaptan therapy should not exceed 4 days.

Drug interactions

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Contraindications

Hypovolemic hyponatremia.

Concomitant use of potent inhibitors of cytochrome P-450 (CYP) isoenzyme 3A (e.g., clarithromycin, indinavir, itraconazole, ketoconazole, ritonavir). (See Inhibitors of Cytochrome P-450 3A Isoenzyme under Drug Interactions: Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes.)

Anuria. Anuric patients are not expected to obtain clinical benefit from conivaptan therapy.

The manufacturer states that solutions containing dextrose, including commercially available premixed conivaptan hydrochloride in 5% dextrose injection, are contraindicated in patients with known allergy to corn or corn products.

Adverse reactions

Adverse effects reported in about 5% or more of individuals receiving conivaptan and more frequently than in those receiving placebo include infusion site reactions (including erythema, pain, phlebitis), hypokalemia, headache, peripheral edema, vomiting, diarrhea, constipation, hypertension, orthostatic hypotension, hyponatremia, thirst, anemia, hypotension, pyrexia, nausea, and confusion.

Precautions

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ICD codes

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Formulary status

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Last reviewed · Source: First Databank (FDB) drug data