Vasopressin in 0.9% Sodium Chloride

Inspect parenteral drug products for particulate matter and discoloration prior to use, whenever solution and container permit.

This product does not require further dilution prior to 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 by intravenous infusion

Septic Shock: 0.01 units/minute by intravenous infusion

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 postcardiotomy 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 in Sodium Chloride Injection by 0.005 units/minute every hour as tolerated to maintain target blood pressure.

A decrease in cardiac index may be observed with the use of vasopressin.

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.

Postmarketing Experience

Reversible diabetes insipidus [see Warnings and Precautions (5.2)]

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.

Use with indomethacin may prolong the effect of Vasopressin in Sodium Chloride Injection on cardiac index and systemic vascular resistance. Hemodynamic monitoring is recommended; adjust the dose of vasopressin as needed [see Clinical Pharmacology (12.3)].

Use with ganglionic blocking agents may increase the effect of Vasopressin in Sodium Chloride Injection on mean arterial blood pressure. Hemodynamic monitoring is recommended; adjust the dose of vasopressin as needed [see Clinical Pharmacology (12.3)].

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 in Sodium Chloride Injection. Hemodynamic monitoring is recommended; adjust the dose of vasopressin as needed.

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 in Sodium Chloride Injection. Hemodynamic monitoring is recommended; adjust the dose of vasopressin as needed.

There are no data on the presence of Vasopressin in Sodium Chloride Injection in either human or animal milk, the effects on the breastfed infant, or the effects on milk production.

Safety and effectiveness of Vasopressin in Sodium Chloride Injection in pediatric patients with vasodilatory shock have not been established.

Clinical studies of vasopressin did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy [see Warnings and Precautions (5), Adverse Reactions (6), and Clinical Pharmacology (12.3)].

Vasopressin causes vasoconstriction by binding to V₁ receptors on vascular smooth muscle coupled to the Gq/11-phospholipase C-phosphatidyl-inositol-triphosphate pathway, resulting in the release of intracellular calcium. In addition, vasopressin stimulates antidiuresis via stimulation of V₂ receptors which are coupled to adenyl cyclase.

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 V₁-receptors and release of prolactin and ACTH via V₃ receptors. At lower concentrations typical for the antidiuretic hormone vasopressin inhibits water diuresis via renal V₂ receptors. In addition, vasopressin has been demonstrated to cause vasodilation in numerous vascular beds that are mediated by V₂, V₃, oxytocin and purinergic P2 receptors.

In patients with vasodilatory shock vasopressin in therapeutic doses increases systemic vascular resistance and mean arterial blood pressure and reduces the dose requirements for norepinephrine. Vasopressin tends to decrease heart rate and cardiac output. The pressor effect is proportional to the infusion rate of exogenous vasopressin. The pressor effect reaches its peak within 15 minutes. After stopping the infusion the pressor effect fades within 20 minutes. There is no evidence for tachyphylaxis or tolerance to the pressor effect of vasopressin in patients.

Vasopressin plasma concentrations increase linearly with increasing infusion rates from 10 micro-units/kg/min to 200 micro-units /kg/min. Steady state plasma concentrations are achieved after 30 minutes of continuous intravenous infusion.

No formal carcinogenicity or fertility studies with vasopressin have been conducted in animals. Vasopressin was found to be negative in the in vitro bacterial mutagenicity (Ames) test and the in vitro Chinese hamster ovary (CHO) cell chromosome aberration test. In mice, vasopressin has been reported to have an effect on function and fertilizing ability of spermatozoa.