Preoperative Euvolemic Hyponatremia in a Burn Patient

Diagnosis

Thiazide-induced euvolemic hyponatremia with associated hypochloremia

Why VAPRISOL was chosen for treatment

Patient required prompt surgery to treat burn wounds and minimize burn-related morbidities
Due to the presentation of euvolemic hyponatremia and the potential for significant complications such as acute seizure disorder, general anesthesia was contraindicated
Hyponatremia was determined to be thiazide-induced; alcohol (ETOH) dependency was considered negligible
VAPRISOL blocks the V₂ receptors in the collecting ducts of the kidneys, resulting in aquaresis, and the raising of serum sodium levels
VAPRISOL treatment was started on the medical floor; within 24 hours serum sodium levels were raised to near normal, allowing rapid transfer to the operating room (OR)

Initial Presentation

A 42-year-old white male was admitted to the Burn Unit with 15% Total Body Surface Area (TBSA) deep-partial thickness burns to his upper and lower extremities resulting from misuse of an accelerant. There was no evidence of trauma, inhalation injury, or loss of consciousness. The patient was intoxicated when the injury occurred.

Medical History

Essential hypertension
Alcohol (ETOH) dependency

Medications

Hydrochlorothiazide (HCTZ) 25-mg daily for the last 2 years

Exam Findings

Vital Signs	Weight: 160 lb, Temperature: 99.0°F, BP: 150/90 mm Hg, HR: 100 bpm, RR: 18
Chest X-ray	No acute changes, chronic obstructive lung disease pattern
EKG	Normal sinus rhythm at 100, nonspecific ST-T wave changes and voltage criteria for left ventricular hypertrophy (LVH). Remainder unremarkable.

Patient’s progression from admission to discharge at day 4

	VITAL SIGNS			LAB VALUES
	BP (mm Hg)	HR (bpm)	Weight (lb)	Urine Output (cc/hour)	Serum Osmolality (mOsm/kg-H_2O)	Urine Na+ (mEq/L)	Serum Na+ (mEq/L)	NOTES
Upon Admission	150/90	100	160	30	405	201	126	Patient diagnosed with euvolemic hyponatremia based on laboratory findings. Patient first received normal saline solution, then a loading dose of VAPRISOL 20-mg IV was administered over 30 minutes, followed by a 20-mg continuous IV infusion to be administered over 24 hours.
Day 1	130/72	90	160	60	—	—	134	Patient admitted to the OR. A 20-mg continuous IV infusion of VAPRISOL was administered over 24 hours, including during the procedure.
Day 2	136/78	84	160	50	208	80	138	VAPRISOL infusion discontinued.
Day 3	—	—	—	—	—	—	137	Remained in-patient for post-surgical observation.
Day 4	—	—	—	—	—	—	139	Serum sodium level maintained within normal range*; patient discharged to his home.

*The effect of VAPRISOL on the maintenance of serum sodium concentration is not known.¹

REFERENCE: 1. Vaprisol^® [Package Insert] Cumberland Pharmaceuticals Inc. Nashville, TN 2016

View Full Prescribing Information

Indication: VAPRISOL is indicated to raise serum sodium in hospitalized patients with euvolemic and hypervolemic hyponatremia.
Important Limitations: VAPRISOL has not been shown to be effective for the treatment of the signs and symptoms of heart failure and is not approved for this indication. It has not been established that raising serum sodium with VAPRISOL provides a symptomatic benefit to patients.

IMPORTANT SAFETY INFORMATION

CONTRAINDICATIONS
VAPRISOL is contraindicated in patients with hypovolemic hyponatremia. The coadministration of VAPRISOL with potent CYP3A inhibitors, such as ketoconazole, itraconazole, clarithromycin, ritonavir, and indinavir, is contraindicated. In addition, no benefit can be expected in patients unable to make urine.

WARNINGS & PRECAUTIONS
Hyponatremia associated with heart failure: Safety data on the use of VAPRISOL in these patients are limited. Consider other treatment options.
Overly rapid correction of serum sodium: Monitor serum sodium, volume and neurologic status and if the patient develops an undesirably rapid rate of rise of serum, VAPRISOL should be discontinued. If serum sodium concentration continues to rise, VAPRISOL should not be resumed. Serious neurologic sequelae, including osmotic demyelination syndrome, can result from over rapid correction of serum sodium. In susceptible patients, including those with severe malnutrition, alcoholism or advanced liver disease, slower rates of correction should be used.
Hypovolemia or Hypotension: For patients who develop hypovolemia or hypotension while receiving VAPRISOL, VAPRISOL should be discontinued, and volume status and vital signs should be monitored.
Infusion site reactions: Serious reactions have occurred. Administer through large veins and change infusion site every 24 hours.

ADVERSE REACTIONS
The most common adverse reactions (incidence ≥10%) reported in clinical trials were infusion site reactions (including phlebitis), pyrexia, hypokalemia, headache and orthostatic hypotension.

DRUG INTERACTIONS
Potent CYP3A inhibitors may increase the exposure of conivaptan and are contraindicated. Generally avoid CYP3A substrates. Exposure to coadministered digoxin may be increased and digoxin levels should be monitored.

USE IN SPECIAL POPULATIONS
Use in Patients with Hepatic Impairment
In patients with moderate to severe hepatic impairment, initiate VAPRISOL with a loading dose of 10 mg over 30 minutes followed by 10 mg/day as a continuous infusion for 2 to 4 days. If no rise in serum sodium, VAPRISOL may be titrated upward to 20 mg/day.