Vasopressin (Vasostrict, Par) is available as a 20-units/mL concentrate for injection in 1-mL single-dose vials and 10-mL multiple-dose vials.3000 Each mL of the concentrate contains vasopressin 20 units and sodium acetate 1.36 mg in water for injection with sodium hydroxide and hydrochloric acid for pH adjustment; multiple-dose vials also contain chlorobutanol 0.5% as a preservative.3000 Vasopressin 20-units/mL concentrate (American Regent) also is available in 1-mL single-dose vials containing vasopressin 20 units, chlorobutanol 0.5%, and sodium chloride 9 mg in water for injection with acetic acid for pH adjustment.3835
Vasopressin also is available as a premixed, ready-to-use solution in concentrations of 0.2, 0.4, and 0.6 unit/mL in 100-mL single-dose vials.3000 Each mL of the premixed solutions contains vasopressin 0.2, 0.4, or 0.6 unit, acetic acid 0.0546 mg, sodium acetate 0.012 mg, and dextrose 5% in water for injection.3000 Sodium hydroxide and hydrochloric acid are used for pH adjustment.3000
pH
The concentrate has a pH of 3.5 (American Regent)3835 or 3.8 (Vasostrict, Par).3000 The premixed solutions (Vasostrict, Par) have a pH of 3.8.3000
Trade Name(s)
Vasostrict
Vasopressin injection is administered by intravenous infusion.3000 The concentrate for injection should be diluted to a concentration of 0.1 or 1 unit/mL in sodium chloride 0.9% or dextrose 5% and inspected for particulate matter and discoloration prior to use.3000
The drug also has been administered by intramuscular or subcutaneous injection;3002 however, approved labeling no longer includes information on these routes.3000
Vasopressin concentrate and premixed solutions are clear, colorless solutions.3000; 3835 Intact vials should be stored at 2 to 8°C and protected from freezing.3000 Intact vials removed from refrigeration can be stored at controlled room temperature for up to 12 months or until the manufacturer’s original expiration date (whichever is shorter) at any time within the labeled shelf life.3000; 3001; 3835
Following initial vial entry, multiple-dose vials should be stored under refrigeration and discarded 30 days after initial entry.3000 Unused portions of single-dose vials should be discarded after use.3000; 3835 Diluted solutions should be discarded after 18 hours at room temperature or 24 hours under refrigeration.3000; 3835
Standardize 4 Safety
One or more standardized concentrations for this drug have been established through Standardize 4 Safety (S4S), a national patient safety initiative to reduce medication errors, especially during transitions of care. (See Standardize 4 Safety in Users Guide.) Recommendations developed to date through this initiative are available at www.ashp.org/pharmacy-practice/standardize-4-safety-initiative.
Table 1. Standardize 4 Safety Continuous IV Infusion Standard Concentrations for Vasopressin3635; 3636
| Patient Population | Concentration Standards | Dosing Units |
|---|---|---|
| Adults | 0.2 unit/mL 0.4 unit/mL 1 unit/mL | units/minute or units/kg/minutea |
| Pediatric patients (50 kg) | 0.05 unit/mL 0.2 unit/mL 1 unit/mL | Vasoconstriction/GI Bleed: milliunits/kg/minute (note dosing units differ from concentration units) Diabetes Insipidus: milliunits/kg/hour (note dosing units differ from concentration units) |
aThe S4S panel recommends trying to standardize dosing units but understands that some protocols may use “flat” dosing while others may require weight-based dosing.
For a list of references cited in the text of this monograph, search the monograph titled References.