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. |
| Molecular Weight | 1084.23 |
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 | Insufficient human data; animal studies not available. Use only if potential benefit justifies potential risk to fetus. Vasopressors may reduce placental perfusion. |
| 2nd trimester | Insufficient human data; use only if clearly needed. Monitor for maternal hypertension and fetal heart rate. |
| 3rd trimester | Insufficient human data; use only if clearly needed. Monitor for maternal hypertension and fetal heart rate. |
Clinical note
Comprehensive clinical and safety monograph for VASOSTRICT (VASOSTRICT).
| Placental transfer | Limited data; vasopressin is a large peptide (MW ~1084 Da) with low expected placental transfer. No specific studies. |
| Breastfeeding | No data on excretion in human milk. Consider risk of hypertension in infant. Caution; use only if clearly needed. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to vasopressin or any component
| 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 |
| Food/Dietary | No specific food interactions. However, fluid and sodium intake may be managed to address hyponatremia risk. Avoid excessive water intake that could dilute sodium levels. |
Loading safety data…
| Lactation Rating |
| L3 (Moderately Safe) |
| 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 | 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. |
| Clinical Pearls |
| VASOSTRICT (vasopressin) is used for vasodilatory shock (e.g., septic shock) as a second-line agent after catecholamines. Monitor for hyponatremia, mesenteric ischemia, and cardiac ischemia. Avoid in patients with coronary artery disease. Titrate to target mean arterial pressure (MAP) ≥65 mmHg. Use with caution in patients with asthma or migraine due to potential bronchoconstriction and vasoconstriction. |
| Patient Advice | This medication is given intravenously to raise blood pressure during shock. · You will be closely monitored for side effects like low sodium, reduced blood flow to the gut or heart. · Report any chest pain, abdominal pain, numbness, or tingling immediately. · Do not stop or adjust the infusion rate without your healthcare provider's instruction. |