CC Pharm | Vasopressin

Vasopressin (Vasostrict) Clinical Reference 1. Action: Exogenous ADH analog. Promotes renal water reabsorption via cAMP. Directly contracts vascular smooth muscle non-adrenergically. 2. Use: Raising BP in vasodilatory shock refractory to fluids/catecholamines; post-op abdominal distention. 3. Complications: Cardiac arrest, bradycardia, MI, AFib, water intoxication, severe hyponatremia, necrosis. 4. Admin: IV infusion must go through central vein. If peripheral, use >=20G catheter & check frequently. Premixed (0.4/0.6 units/mL) needs no dilution. Dilute 20 units/mL to 0.1 or 1 unit/mL in NS/D5W. Discard after 18h room temp, 24h refrigerated. IM/SC duration is 2-8h; IO used in CPR. 5. Contraindications: No renal/hepatic adjustments needed. Caution in coronary artery disease (ischemia risk). 6. Nursing: Monitor ECG, BP, fluids, sites. For extravasation, inject 5-10 mg phentolamine directly. 7. Interactions: Muscle contraction not blocked by adrenergic blockers/denervation. No CYP450 interactions. 8. Education: ICU drug; explain central line need and to report chest pain or IV burning. 9. Evaluation: Increased MAP, catecholamine-sparing, stable sodium/osmolality. 10. Why Choose? Bypasses catecholamine resistance. Onset peaks <15 min; fades <20 min of stopping. 11. Pearls: Most Dangerous: MI, tissue necrosis. Key Lab: Serum sodium (detects hyponatremia). Antidote: Phentolamine 5-10 mg for extravasation. NCLEX/ATI: Run through central line to prevent necrosis. 12. Scenario: Septic shock patient hypotensive on norepinephrine. Adding vasopressin raises MAP, allowing down-titration of toxic catecholamines. 13. Mnemonic: Vasopressin Presses Vessels (V1 constriction) & Preserves Volume (V2 reabsorption). THE 20% I ABSOLUTELY NEED TO KNOW Catecholamine-Saver: Works on non-adrenergic receptors, maintaining potency in severe acidotic shock where catecholamine receptors are down-regulated. Extravasation Rescue: High necrosis risk peripherally. Immediately inject 5-10 mg phentolamine to site if extravasation occurs. Water Retention: Exogenous ADH action causes renal water retention, causing dilutional hyponatremia/water intoxication. IF I REMEMBER NOTHING ELSE Direct non-adrenergic vasoconstrictor with strong catecholamine-sparing effect. IV onset peaks <15 min; pressor effects fade <20 min of stopping. Central line infusion preferred; extravasation causes severe skin necrosis. Phentolamine (5-10 mg) is the antidote for local extravasation. Conserves free water; monitor closely for hyponatremia. No hepatic or renal dosage adjustments are required.