VASOPRESSIN

Vasopressin injection is indicated to increase blood pressure in adults with vasodilatory shock who remain hypotensive despite fluids and catecholamines.

2.1 Preparation of Diluted Solutions Inspect parenteral drug products for particulate matter and discoloration prior to use, whenever solution and container permit. Vasopressin Injection Solution for Dilution, 20 units/mL and 200 units/10 mL (20 units/mL). Dilute vasopressin injection in 0.9% Sodium Chloride Injection or 5% Dextrose Injection prior to use for intravenous infusion. (See Table 1). Discard unused diluted solution after 18 hours at room temperature or 24 hours under refrigeration. 2.2 Administration In general, titrate to the lowest dose compatible with a clinically acceptable response. The recommended starting dose is: Post-cardiotomy shock: 0.03 units/minute Septic Shock: 0.01 units/minute Titrate up by 0.005 units/minute at 10- to 15-minute intervals until the target blood pressure is reached. There are limited data for doses above 0.1 units/minute for post-cardiotomy shock and 0.07 units/minute for septic shock. Adverse reactions are expected to increase with higher doses. After target blood pressure has been maintained for 8 hours without the use of catecholamines, taper vasopressin injection by 0.005 units/minute every hour as tolerated to maintain target blood pressure. Table

5.1 Worsening Cardiac Function A decrease in cardiac index may be observed with use of vasopressin. 5.2 Reversible Diabetes Insipidus Patients may experience reversible diabetes insipidus, manifested by the development of polyuria, a dilute urine, and hypernatremia, after cessation of treatment with vasopressin. Monitor serum electrolytes, fluid status, and urine output after vasopressin discontinuation. Some patients may require readministration of vasopressin or administration of desmopressin to correct fluid and electrolyte shifts.

Vasopressin injection 1 mL single-dose vial and 10 mL multiple-dose vial are contraindicated in patients with known allergy or hypersensitivity to 8-L-arginine vasopressin or chlorobutanol.

7.1 Catecholamines Use with catecholamines is expected to result in an additive effect on mean arterial blood pressure and other hemodynamic parameters. Hemodynamic monitoring is recommended; adjust the dose of vasopressin as needed. 7.2 Indomethacin Use with indomethacin may prolong the effect of vasopressin injection on cardiac index and systemic vascular resistance. Hemodynamic monitoring is recommended; adjust the dose of vasopressin as needed [see Clinical Pharmacology (12.3)]. 7.3 Ganglionic Blocking Agents Use with ganglionic blocking agents may increase the effect of vasopressin injection on mean arterial blood pressure. Hemodynamic monitoring is recommended; adjust the dose of vasopressin as needed [see Clinical Pharmacology (12.3)]. 7.4 Drugs Suspected of Causing SIADH (Syndrome of Inappropriate Antidiuretic Hormone Secretion) Use with drugs suspected of causing SIADH (e.g., SSRIs, tricyclic antidepressants, haloperidol, chlorpropamide, enalapril, methyldopa, pentamidine, vincristine, cyclophosphamide, ifosfamide, felbamate) may increase the pressor effect in addition to the antidiuretic effect of vasopressin injection. Hemodynamic monitoring is recommended; adjust the dose of vasopressin as needed. 7.5 Drugs Suspected of Causing Diabetes Insipidus Use with drugs suspected of causing diabetes insipidus (e.g., demeclocycline, lithium, foscarnet, clozapine) may decrease the pressor effect in addition to the antidiuretic effect of vasopressin injection. Hemodynamic monitoring is recommended; adjust the dose of vasopressin as needed.

The following adverse reactions associated with the use of vasopressin were identified in the literature. Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to estimate their frequency reliably or to establish a causal relationship to drug exposure. Bleeding/lymphatic system disorders: Hemorrhagic shock, decreased platelets, intractable bleeding Cardiac disorders: Right heart failure, atrial fibrillation, bradycardia, myocardial ischemia Gastrointestinal disorders: Mesenteric ischemia Hepatobiliary: Increased bilirubin levels Renal/urinary disorders: Acute renal insufficiency Vascular disorders: Distal limb ischemia Metabolic: Hyponatremia Skin: Ischemic lesions Postmarketing Experience Reversible diabetes insipidus [see Warnings and Precautions (5.2)].