conivaptan (Vaprisol)

Introduction

Trademark: Vaprisol, FDA approved 2005

Indications

• treatment of euvolemic hyponatremia (SIADH)

Contraindications

• hypovolemia
• congestive heart failure

Dosage

• 20 mg IV over 30 minutes, followed by
• IV infusion of another 20 mg over 24 hours for 1-4 days
• may titrate up to 40 mg/day

Pharmacokinetics

• metabolized by cyt P450 3A4

Adverse effects

• infusion site reactions (50%)
• headache, hypokalemia, GI distress
• hypertension, hypotension

Drug interactions

• coadministration of potent CYP3A4 inhibitors can increase levels of conivaptan & is contraindicated
  • ketoconazole, itraconazole, clarithromycin, ritonavir, indinavir
• monitor digoxin levels

Mechanism of action

• arginine vasopressin antagonist
• increases in serum sodium of > 4 meq/L after 1st dose in 52% of patients Manufacturers: Astellas Pharma US

More general terms

• vasopressin receptor antagonist (vaptan)

Database

• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=151171
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=216322