VASOPRESSIN IN DEXTROSE 5%
Clinical safety rating: safe
Other drugs that can cause water intoxication may have additive effects Can cause hyponatremia and tissue necrosis with extravasation.
Vasopressin binds to V1a receptors on vascular smooth muscle, causing vasoconstriction; binds to V2 receptors in renal collecting ducts, increasing water reabsorption.
| Metabolism | Primarily metabolized by the liver and kidneys via peptidases; not significantly metabolized by CYP enzymes. |
| Excretion | Minimal renal elimination; primarily hepatorenal clearance with extensive extrarenal metabolism; <5% excreted unchanged in urine. |
| Half-life | 10–35 minutes; terminal half-life approximately 15 minutes; clinically short half-life necessitates continuous IV infusion. |
| Protein binding | Approximately 30–50%; bound primarily to albumin; binding is not concentration-dependent. |
| Volume of Distribution | 0.1–0.3 L/kg; low Vd consistent with limited distribution primarily in plasma volume; reflects minimal tissue penetration. |
| Bioavailability | Not available for oral route; IV: 100%; extensive first-pass metabolism precludes oral administration. |
| Onset of Action | IV: Rapid, within 1–2 minutes; onset of vasoconstrictor effect is immediate upon IV administration. |
| Duration of Action | IV: 30–60 minutes; antidiuretic effect lasts up to 2–8 hours at higher doses; vasopressor effect duration is shorter due to rapid metabolism. |
| Molecular Weight | 1084 |
IV: Initial 0.01–0.04 units/min, titrate by 0.005 units/min every 10–15 min to target effect; max 0.1 units/min. Usual maintenance 0.01–0.06 units/min.
| Dosage form | SOLUTION |
| Renal impairment | No specific GFR-based dose adjustment defined; use caution in severe renal impairment (CrCl <30 mL/min) due to fluid overload risk from dextrose. |
| Liver impairment | No formal Child-Pugh based modification; vasopressin may increase portal pressure. Use with caution in Child-Pugh C cirrhosis. |
| Pediatric use | Weight-based: IV 0.0003–0.002 units/kg/min; titrate to effect. Max 0.002 units/kg/min. Alternatively: bolus 0.002–0.01 units/kg/dose for pulseless arrest. |
| Geriatric use | Start at lower end of dosing range (0.01 units/min); monitor for hyponatremia and cardiac ischemia due to increased sensitivity. |
| 1st trimester | Vasopressin is used in critical care settings; limited data suggest potential for uterine hyperstimulation and fetal hypoxia. Use only if clearly needed. |
| 2nd trimester | Same as T1; may cause decreased uterine blood flow. Consider alternative vasopressors if possible. |
| 3rd trimester | Risk of preterm labor or fetal distress due to increased uterine activity. Use only when benefits outweigh risks. |
Clinical note
Other drugs that can cause water intoxication may have additive effects Can cause hyponatremia and tissue necrosis with extravasation.
| FDA category | Animal |
| Placental transfer | Vasopressin likely crosses the placenta due to its small peptide size (molecular weight 1084 Da), but specific data are lacking. |
| Breastfeeding |
■ FDA Black Box Warning
None.
| Common Effects | vasodilatory shock |
| Serious Effects |
History of hypersensitivity to vasopressin or any component of the formulationCardiovascular disease with severe vascular occlusion
| Precautions | Use with caution in patients with coronary artery disease, May cause severe hyponatremia due to antidiuretic effect, Monitor fluid and electrolyte status, May cause ischemia in peripheral, mesenteric, or coronary vascular beds, Extravasation risk |
| Food/Dietary | None specifically; however, monitor sodium and fluid intake to avoid hyponatremia or hypervolemia. Excessive salt intake may counteract vasopressin's antidiuretic effect. |
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| Not recommended due to lack of safety data in lactating women. Vasopressin may be present in milk; potential for adverse effects in the infant. Consider alternative therapies. |
| Lactation Rating | Avoid |
| Teratogenic Risk | Vasopressin is a posterior pituitary hormone. Limited data in human pregnancy. Animal studies show no teratogenic effects at therapeutic doses. Risk cannot be excluded; consider benefit-risk. First trimester: theoretical risk of uteroplacental ischemia; use only if clearly needed. Second/third trimesters: may induce uterine contractions; avoid at term. Category C (US FDA). |
| Fetal Monitoring | Monitor vital signs (blood pressure, heart rate), fluid balance, serum electrolytes, and urine output. Fetal heart rate monitoring if used near term. Assess signs of uterine hypertonus. |
| Fertility Effects | No known direct effects on fertility. High doses may cause uterine contractions and impact conception. Vasopressin is used in some reproductive procedures, but effect on fertility is not established. |
| Clinical Pearls | Vasopressin in D5W is used for vasodilatory shock (e.g., septic shock) as an adjunct to catecholamines. Monitor for hyponatremia and fluid overload due to D5W. Titrate to a target MAP of 65-75 mmHg. High doses may cause coronary or peripheral ischemia. Correct hypovolemia before initiation. |
| Patient Advice | This medication is given intravenously to raise blood pressure. · You will be closely monitored for fluid balance and sodium levels. · Report chest pain, shortness of breath, or decreased urine output. · Do not consume salty foods or excessive fluids without doctor approval. · This is not a treatment for diabetes insipidus when in D5W. |