VASOSTRICT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VASOSTRICT (VASOSTRICT).
Vasopressin is a synthetic analogue of the antidiuretic hormone (ADH) that acts on V1 receptors (vascular smooth muscle) to cause vasoconstriction, and on V2 receptors (renal collecting ducts) to increase water reabsorption. At high doses used in vasodilatory shock, it primarily increases systemic vascular resistance via V1 receptor activation.
| Metabolism | Primarily metabolized in the liver and kidneys by peptide hydrolases (proteolytic degradation); excreted in urine. |
| Excretion | Primarily renal (90–95% as inactive metabolites); minor biliary/fecal excretion (<5%). |
| Half-life | Terminal elimination half-life is approximately 10–20 minutes, with clinical effect terminated rapidly by enzymatic degradation (catechol-O-methyltransferase and monoamine oxidase) in the liver and other tissues. |
| Protein binding | Approximately 30–40% bound, primarily to albumin and alpha1-acid glycoprotein. |
| Volume of Distribution | 0.2–0.3 L/kg, indicating primarily extracellular distribution and limited tissue binding. |
| Bioavailability | Intravenous only; no bioavailability data for other routes as vasopressin is administered exclusively parenterally (IV). |
| Onset of Action | Intravenous: immediate (within 1–2 minutes). |
| Duration of Action | Approximately 5–10 minutes after IV infusion cessation, consistent with short half-life; continuous infusion required for sustained effect. |
0.01-0.03 units/min IV continuous infusion, titrate to effect. Maximum 0.1 units/min.
| Dosage form | SOLUTION |
| Renal impairment | No dosage adjustment required for renal impairment. Use with caution in severe renal impairment due to potential for decreased clearance. |
| Liver impairment | No specific adjustment guidelines for Child-Pugh classification. Use with caution in severe hepatic impairment due to reduced metabolism. |
| Pediatric use | Not FDA-approved for pediatric use. Limited data: 0.0005-0.01 units/kg/min IV continuous infusion, titrated to desired effect. |
| Geriatric use | No specific dosage adjustment. Initiate at lower end of dosing range (0.01 units/min) and titrate cautiously due to increased sensitivity and risk of adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VASOSTRICT (VASOSTRICT).
| Breastfeeding | Not known if excreted in human milk. M/P ratio unknown. Caution due to potential for vasoconstriction in infant. Consider alternative agents during breastfeeding. |
| Teratogenic Risk | FDA Pregnancy Category C. Animal studies show fetal harm; no adequate human studies. Vasopressin may reduce uterine blood flow causing fetal hypoxia. Use only if benefit outweighs risk; avoid in first trimester unless life-threatening. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to vasopressin or any component","Use in patients with active coronary ischemia (relative)"]
| Precautions | ["Caution in patients with epilepsy, migraine, asthma, or heart failure due to risk of fluid overload or vasoconstriction","Monitor fluid and electrolyte balance; may cause hyponatremia","Avoid extravasation due to risk of tissue necrosis","Risk of mesenteric ischemia at high doses","Use with caution in patients with coronary artery disease or peripheral vascular disease"] |
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| Continuous fetal heart rate monitoring during infusion. Monitor maternal blood pressure, heart rate, urine output, and signs of ischemia (cardiac, peripheral). Assess for hyponatremia and fluid overload. |
| Fertility Effects | No clinical data on fertility. Animal studies show no impairment of fertility at therapeutic doses. Potential for ovarian vasoconstriction at high doses. |