conivaptan


conivaptan

(con-i-vap-tan) conivaptan,

Vaprisol

(trade name)

Classification

Therapeutic: electrolyte modifiers
Pharmacologic: vasopressin antagonists
Pregnancy Category: C

Indications

To increase serum sodium in hospitalized patients with euvolemic or hypervolemic hyponatremia.

Action

Antagonizes vasopressin at V2 receptor sites in renal collecting ducts, resulting in excretion of free water.

Therapeutic effects

Increased serum sodium concentrations.Improved fluid status.

Pharmacokinetics

Absorption: IV administration results in complete bioavailability.Distribution: Unknown.Protein Binding: 99% protein bound.Metabolism and Excretion: Metabolized solely by the CYP3A4 enzyme system. 83% excreted in feces as metabolites, 12% in urine (as metabolites).Half-life: 5 hr.

Time/action profile

ROUTEONSETPEAKDURATION
IVunknown12 hrend of infusion

Contraindications/Precautions

Contraindicated in: Hypersensitivity;Hypovolemic hyponatremia;Concurrent use of ketonconazole, itraconazole, clarithromycin, ritonavir, or indinavir.Use Cautiously in: Moderate hepatic impairment (↓ dose recommended)Severe renal impairment (not recommended if CCr <30 mL/min); Obstetric / Lactation: Safety not established; Pediatric: Safety not established.

Adverse Reactions/Side Effects

Central nervous system

  • headache (most frequent)
  • confusion
  • insomnia

Cardiovascular

  • hypertension
  • hypotension

Gastrointestinal

  • diarrhea

Genitourinary

  • polyuria

Fluid and Electrolyte

  • dehydration
  • hypokalemia
  • hypomagnesemia
  • hyponatremia

Local

  • infusion reactions (most frequent)

Miscellaneous

  • fever
  • thirst

Interactions

Drug-Drug interaction

Blood levels and effects are ↑ by ketoconazole, itraconazole, clarithromycin, ritonavir, or indinavir ; concurrent use is contraindicated.↑ blood levels and may ↑ effects of midazolam, simvastatin, lovastatin, amlodipine, and other drugs metabolized by CYP3A4 ; careful monitoring recommended.May ↑ digoxin levels.

Route/Dosage

Intravenous (Adults) 20 mg loading dose initially, followed by 20 mg/day as a continuous infusion for 2–4 days. May titrate conivaptan up to 40 mg/day as a continuous infusion if serum sodium is not rising at desired rate. Total duration of therapy should not exceed 4 days.

Hepatic Impairment

(Adults) Moderate hepatic impairment—10 mg loading dose initially, followed by 10 mg/day as a continuous infusion for 2–4 days; may titrate up to 20 mg/day as a continuous infusion if serum sodium is not rising at desired rate.

Availability

Premixed infusion: 20 mg/100 mL D5W

Nursing implications

Nursing assessment

  • Monitor injection site during administration. Frequently causes erythema, pain, swelling and phlebitis. May require discontinuation of therapy.
  • Monitor vital signs frequently during therapy. Discontinue therapy if patient becomes hypovolemic and hypotensive. Therapy may be resumed at a reduced dose once patient is euvolemic and no longer hypotensive, if patient remains hyponatremic.
  • Assess neurologic status during administration. Overly rapid rise in serum sodium may cause neurologic sequelae.
  • Lab Test Considerations: Monitor serum sodium concentration frequently during therapy. If serum sodium rises at an undesirably rapid rate (>12 mEq/L/24 hr), discontinue administration of conivaptan. If serum sodium continues to rise, do not resume therapy. If hyponatremia persists or recurs (after discontinuation for rapid rise of serum sodium) and patient has no evidence of neurologic sequelae from rapid increase, conivaptan may be resumed at a reduced dose.
    • May cause hyperglycemia, hypoglycemia, hypokalemia, hypomagnesemia, and hyponatremia.

Potential Nursing Diagnoses

Deficient knowledge, related to medication regimen (Patient/Family Teaching)

Implementation

  • Intravenous Administration
  • Administer IV through large veins and rotate infusion site every 24 hr to minimize risk if vascular irritation.
    • Loading Dose
  • Intermittent Infusion: Diluent: Premixed containers require no further dilution.Concentration: 0.2 mg/mL.
  • Rate: Administer over 30 min.
    • Continuous Infusion
  • Continuous Infusion: Diluent: Premixed containers require no further dilution.Concentration: 0.2 mg/mL.
  • Rate: Administer continuous infusion at a rate of 20 mg/24 hr. If patient requires 40 mg/24 hr continuous infusion, infuse 20 mg over 12 hr, followed by 20 mg over 12 hr.
  • Additive Incompatibility: Do not admix with LR, furosemide, or combine with any other product in the same IV line or bag.

Patient/Family Teaching

  • Explain purpose of medication to patient.
  • Instruct patient to notify health care professional if pain or redness occurs at infusion site.

Evaluation/Desired Outcomes

  • Restoration of normal fluid and electrolyte balance.