Overview
11 DESCRIPTION Vasopressin is a polypeptide hormone. Vasopressin injection is a sterile, aqueous solution of synthetic arginine vasopressin for intravenous administration. The 1 mL solution contains vasopressin 20 units/mL, 1.36 mg sodium acetate buffer and Water for Injection, USP. Sodium hydroxide and hydrochloric acid are included to adjust to a pH of 3.8.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Vasopressin causes vasoconstriction by binding to V 1 receptors on vascular smooth muscle coupled to the Gq/1 1-phospholipase C-phosphatidyl-inositol-triphosphate pathway, resulting in the release of intracellular calcium. In addition, vasopressin stimulates antidiuresis via stimulation of V 2 receptors which are coupled to adenyl cyclase. 12.2 Pharmacodynamics At therapeutic doses exogenous vasopressin elicits a vasoconstrictive effect in most vascular beds including the splanchnic, renal and cutaneous circulation. In addition, vasopressin at pressor doses triggers contractions of smooth muscles in the gastrointestinal tract mediated by muscular V 1 -receptors and release of prolactin and ACTH via V 3 receptors.
Indications
- 1 INDICATIONS AND USAGE Vasopressin injection is indicated to increase blood pressure in adults with vasodilatory shock who remain hypotensive despite fluids and catecholamines. • Vasopressin injection is indicated to increase blood pressure in adults with vasodilatory shock who remain hypotensive despite fluids and catecholamines. ( 1 )
Common Doses
- 2.5 mL
- 500 mL
- 5 mL
- 100 mL
Dosage
2 DOSAGE AND ADMINISTRATION • Dilute 20 units/mL single dose vial contents with normal saline (0.9% sodium chloride) or 5% dextrose in water (D5W) to either 0.1 units/mL or 1 unit/mL for intravenous administration. Discard unused diluted solution after 18 hours at room temperature or 24 hours under refrigeration. ( 2.1 ) • Post-cardiotomy shock: 0.03 to 0.1 units/minute ( 2.2 ) • Septic shock: 0.01 to 0.07 units/minute ( 2.2 ) 2.1 Preparation of Solution Inspect parenteral drug products for particulate matter and discoloration prior to use, whenever solution and container permit.
Contraindications
- 4 CONTRAINDICATIONS Vasopressin injection 1 mL single dose vial does not contain chlorobutanol and is therefore contraindicated only in patients with a known allergy or hypersensitivity to 8-L-arginine vasopressin. • Vasopressin injection 1 mL single dose vial does not contain chlorobutanol and is therefore contraindicated only in patients with a known allergy or hypersensitivity to 8-L-arginine vasopressin. ( 4 )
Side Effects
- 6 ADVERSE REACTIONS 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...
Interactions
- 7 DRUG INTERACTIONS • Pressor effects of catecholamines and Vasopressin injection are expected to be additive. ( 7.1 ) • Indomethacin may prolong effects of Vasopressin injection. ( 7.2 ) • Co-administration of ganglionic blockers or drugs causing SIADH may increase the pressor response. ( 7.3 , 7.4 ) • Co-administration of drugs causing diabetes insipidus may decrease the pressor response. ( 7.5 ) 7.1 Catecholamines Use with catecholamines is expected to result in an additive effect on mean arterial blood pressure and other hemodynamic parameters.