Guide — Critical Care · Cardiac
Inotropes for Nurses Guide
Positive inotropes in critical care — dobutamine (beta-1 inotropy), milrinone (PDE-3 inodilator, effective with beta-blockade), dopamine (dose-dependent), epinephrine (potent inotrope/vasoconstrictor), and digoxin (glycoside): mechanisms, hemodynamic effects, indications, monitoring parameters, and NCLEX pearls.
11 min read · Critical Care · Cardiac
Educational use only. Inotrope selection and dosing require provider orders and hemodynamic assessment. Infusions of vasoactive medications require continuous monitoring and should only be administered by nurses trained in critical care or acute care settings. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Inotrope Terminology
| Inotrope | Drug that increases myocardial contractility (positive inotrope) or decreases it (negative inotrope). Positive inotropes increase stroke volume, cardiac output, and cardiac index. |
| Vasopressor | Drug that increases systemic vascular resistance (SVR) → raises MAP. Primary mechanism is vasoconstriction (e.g., norepinephrine, vasopressin, phenylephrine). Used when BP is inadequate. |
| Inodilator | Drug with BOTH positive inotropic AND vasodilatory effects (reduces afterload). Milrinone is the classic example. Uniquely beneficial in right heart failure and PAH (lowers PVR and increases RV contractility simultaneously). |
| Chronotrope | Drug affecting heart rate. Positive chronotrope = increases HR (dobutamine, dopamine, epinephrine). Negative chronotrope = decreases HR (digoxin, beta-blockers). |
Inotrope Agents
Dobutamine
Beta-1 adrenergic agonist (+ mild beta-2)
| Mechanism | Stimulates beta-1 receptors in myocardium → increased cAMP → increased intracellular calcium → increased contractility (positive inotropy) and some increase in heart rate. Mild beta-2 peripheral vasodilation (can cause hypotension). |
| Hemodynamics | ↑ Cardiac output (CO), ↑ cardiac index (CI), ↑ stroke volume, mild ↓ SVR (vasodilation), mild ↑ HR, ↓ PCWP (reduces cardiac filling pressure), ↑ myocardial O₂ consumption |
| Indications | Cardiogenic shock (low CO, high PCWP), acute decompensated heart failure (ADHF) refractory to diuretics, cardiac stress testing (dobutamine stress echo), post-cardiac surgery low output state |
| Dosing | 2.5–20 mcg/kg/min IV infusion. Titrate to effect (target cardiac output, clinical perfusion improvement). Infused centrally preferred but peripheral line acceptable for short-term. |
| Side Effects | Tachycardia (most common — limits dose), palpitations, hypotension (beta-2 vasodilation), ventricular arrhythmias (PVCs, VT), increased myocardial O₂ demand (problematic in ischemia), tolerance with prolonged use (> 72h) |
| Monitoring | Continuous cardiac telemetry (tachyarrhythmias). BP every 15–30 min when initiating, then hourly. Heart rate (hold or reduce dose if HR > 110–120). Urine output (marker of improved CO). Lactate clearance. Clinical perfusion signs (CRT, mental status, skin temperature). |
| Nursing Notes | Titrate to clinical response, not fixed dose. Wean gradually — abrupt discontinuation in HF patients can cause acute decompensation. Does NOT require central line but central line improves accuracy. Ineffective in patients on chronic high-dose beta-blockers (receptor competition — use milrinone instead). Dobutamine is a positive inotrope WITHOUT significant vasoconstriction (unlike norepinephrine). |
| NCLEX Pearl | Dobutamine = positive INOTROPE (increases contractility). Does NOT raise SVR significantly (unlike vasopressors). Used for low-CO states. Tachycardia is the dose-limiting side effect. NOT effective with high-dose beta-blocker use. |
Milrinone
Phosphodiesterase-3 (PDE-3) inhibitor — inodilator
| Mechanism | Inhibits PDE-3 → prevents cAMP breakdown → increased intracellular cAMP → increased contractility (inotropy) AND vasodilation (reduces afterload and preload). Acts on both cardiac and vascular smooth muscle. Does NOT work through adrenergic receptors — effective even with beta-blockade. |
| Hemodynamics | ↑ CO, ↑ CI, ↑ stroke volume, ↓↓ SVR (strong vasodilation), ↓↓ PVR (pulmonary vasodilation — unique advantage), ↓ PCWP, mild ↑ HR, significant risk of hypotension |
| Indications | Cardiogenic shock when dobutamine insufficient or patient on beta-blockers, right ventricular failure (PAH patients — lowers PVR), decompensated HF awaiting transplant/destination therapy (bridge), post-cardiac surgery biventricular failure |
| Dosing | Loading dose (optional, often omitted due to hypotension): 50 mcg/kg over 10 min. Maintenance: 0.125–0.75 mcg/kg/min. Renally cleared — REDUCE dose if eGFR reduced. Requires dose reduction in CKD. |
| Side Effects | HYPOTENSION (most significant — inodilator property causes vasodilation), ventricular arrhythmias, thrombocytopenia (rare), headache |
| Monitoring | Continuous cardiac monitoring (arrhythmias). BP every 15–30 min — hypotension is the primary limiting side effect. Platelet count (thrombocytopenia risk). Creatinine (renally cleared — dose adjust). Urine output and clinical perfusion markers. |
| Nursing Notes | Milrinone works EVEN WITH BETA-BLOCKADE — preferred over dobutamine in patients on high-dose beta-blockers. Aggressive hypotension management required — may need concurrent vasopressor. Loaded slowly if at all — loading dose frequently omitted. Right heart failure + PAH: milrinone is ideal (lowers PVR + improves RV contractility). |
| NCLEX Pearl | Milrinone = inodilator (inotropy + vasodilation). Works with beta-blockers (no adrenergic receptor pathway). Renally cleared — reduce dose in CKD. Major side effect = HYPOTENSION. Preferred for RV failure and PAH patients. |
Dopamine
Catecholamine — dose-dependent receptor activity (D1, beta-1, alpha-1)
| Mechanism | Low doses (1–3 mcg/kg/min): dopaminergic (D1) — renal and splanchnic vasodilation. Medium doses (3–10 mcg/kg/min): beta-1 predominant — inotropy, chronotropy, increased CO. High doses (> 10 mcg/kg/min): alpha-1 predominant — vasoconstriction (similar to norepinephrine). NOTE: 'renal-dose dopamine' to protect kidneys is NOT recommended — no outcome benefit proven. |
| Hemodynamics | Dose-dependent: low → renal vasodilation; medium → ↑ CO, ↑ HR; high → ↑ SVR, ↑ BP. Tachycardia and arrhythmias are significant at higher doses. |
| Indications | Cardiogenic shock (medium to high doses); hypotension with bradycardia (medium doses with chronotropic effect); increasingly replaced by norepinephrine for septic shock (SOAP II trial: norepinephrine superior outcomes vs dopamine). |
| Dosing | 1–20 mcg/kg/min IV infusion. Titrate based on hemodynamic goals. Requires central line at high doses (vesicant — causes severe tissue necrosis with extravasation). |
| Side Effects | Tachycardia (major dose-limiting side effect), ventricular arrhythmias (more than norepinephrine — reason SOAP II trial favored norepinephrine), peripheral vasoconstriction at high doses, tissue necrosis with extravasation |
| Monitoring | Continuous cardiac monitoring (tachyarrhythmias, VT). BP every 15–30 min. Urine output. Signs of extravasation (infuse centrally when possible). Lactate. |
| Nursing Notes | Dopamine is a vesicant — must be administered via central line at therapeutic doses. If extravasation occurs: phentolamine 5–10 mg in 10 mL NS injected SC into extravasated area (alpha blockade reverses vasoconstriction). Current evidence supports norepinephrine as preferred vasopressor in septic shock over dopamine. |
| NCLEX Pearl | Dopamine is dose-dependent: LOW = renal vasodilation; MID = inotrope/chronotrope; HIGH = vasoconstrictor. 'Renal-dose dopamine' is NOT evidence-based. SOAP II trial: norepinephrine preferred over dopamine for septic shock (less arrhythmias). Dopamine is a vesicant — use central line. |
Epinephrine (Inotrope/Vasoconstrictor Use)
Endogenous catecholamine — alpha-1, beta-1, beta-2 agonist
| Mechanism | LOW doses (0.01–0.1 mcg/kg/min): beta predominant — inotropy, chronotropy, bronchodilation, some vasodilation (beta-2). HIGH doses (> 0.1 mcg/kg/min): alpha-1 predominance — vasoconstriction added to inotropic effects. Acts on heart (beta-1), vasculature (alpha-1/beta-2), and bronchi (beta-2). |
| Hemodynamics | ↑↑ CO (very potent inotropy), ↑↑ HR, ↑ SVR at high doses, ↑ MAP. Also: hyperglycemia (beta-2 → glycogenolysis), elevated lactate (beta-2 → aerobic lactic acid production — falsely elevates lactate). |
| Indications | Refractory cardiogenic shock (dobutamine + vasopressor insufficient), cardiac arrest (pulseless VF/PEA/asystole: 1 mg IV q3–5min), severe anaphylaxis (IM 1:1,000, 0.3–0.5 mg lateral thigh), severe asthma/bronchospasm, post-cardiac surgery with severe biventricular failure |
| Dosing | Inotrope/vasopressor use: 0.01–0.5 mcg/kg/min IV infusion. Cardiac arrest: 1 mg IV q3–5min. |
| Side Effects | Tachycardia, ventricular arrhythmias, severe HTN, HYPERGLYCEMIA (beta-2 → liver glycogenolysis), elevated LACTATE (beta-2 → aerobic lactate production — does NOT indicate inadequate resuscitation in this context), excessive vasoconstriction → ischemia |
| Monitoring | Continuous cardiac monitoring. Frequent glucose checks (hyperglycemia). Blood pressure arterial line preferred. Lactate interpretation: epinephrine causes aerobic lactate elevation (beta-2) — do NOT use lactate as sole resuscitation endpoint when on epinephrine infusion. |
| Nursing Notes | Epinephrine-induced lactate elevation is AEROBIC (not from hypoperfusion) — important clinical distinction. When patient is on epinephrine infusion: lactate elevation does not necessarily mean inadequate resuscitation. Must use other perfusion markers (CRT, UO, mental status, ScvO₂) to assess adequacy. |
| NCLEX Pearl | Epinephrine for cardiac arrest: 1 mg IV q3–5min (non-shockable rhythms PEA/asystole; also give after first defibrillation in VF/pVT). Anaphylaxis: IM 1:1,000 (0.3 mg) lateral thigh. Epinephrine causes hyperglycemia (beta-2) and aerobic lactate elevation — NOT a sign of inadequate resuscitation. |
Digoxin (Cardiac Glycoside Inotrope)
Cardiac glycoside — Na/K-ATPase inhibitor
| Mechanism | Inhibits Na/K-ATPase pump → sodium accumulates intracellularly → Na/Ca exchanger reverses → intracellular calcium increases → increased contractility. Also: increases vagal tone (slows AV conduction — useful for rate control in AF). |
| Hemodynamics | Modest ↑ contractility (weaker than catecholamines), ↓ heart rate (via vagal effect — rate control in AF), ↓ AV conduction velocity (slows ventricular rate in AF/atrial flutter) |
| Indications | Chronic systolic HF with preserved left ventricular function that remains symptomatic despite optimal ACE/ARB + beta-blocker + diuretics (adjunctive role — does NOT reduce mortality). Heart failure + atrial fibrillation (rate control). NOT a first-line acute agent. |
| Dosing | Oral: 0.125–0.25 mg/day. IV: 0.25–0.5 mg (loading, given slowly). Narrow therapeutic index: target level 0.5–0.9 ng/mL for HF (levels 1.0–2.0 ng/mL historically but associated with worse outcomes at higher levels). Renally cleared — reduce dose in CKD. |
| Side Effects | DIGITALIS TOXICITY: nausea/vomiting (early GI signs), visual disturbances (yellow-green halos/blurry vision), bradycardia, AV blocks, ventricular arrhythmias (all types possible). Hypokalemia potentiates toxicity dramatically — KEEP K⁺ > 3.5 mEq/L. |
| Monitoring | Digoxin level (trough — before AM dose). Potassium (hypokalemia worsens toxicity). Heart rate (hold if HR < 60/min). ECG (progressive PR lengthening, AV block, ventricular arrhythmias). BUN/Cr (renal impairment reduces clearance → toxicity). |
| Nursing Notes | Hold digoxin if heart rate < 60/min. Correct hypokalemia aggressively — low K⁺ dramatically increases digoxin toxicity risk. Report new nausea, visual changes, or arrhythmias in patient on digoxin. Digibind (digoxin-specific antibody fragments) = antidote for life-threatening toxicity. |
| NCLEX Pearl | Digoxin: hold if HR < 60. Toxicity symptoms = nausea + yellow-green vision + bradycardia/arrhythmias. Hypokalemia potentiates toxicity. Antidote = Digibind. Trough level drawn BEFORE dose. Target level 0.5–0.9 ng/mL for HF. |
Inotrope Monitoring Essentials
| Continuous monitoring | All patients on inotrope infusions require continuous cardiac telemetry. Inotropes increase myocardial oxygen demand and can trigger tachyarrhythmias, ventricular ectopy, or VT. |
| Blood pressure | Arterial line preferred for continuous BP monitoring when on inotropes (especially milrinone — severe hypotension risk). Non-invasive BP every 15–30 min minimum when initiating. |
| Perfusion markers | Urine output (most accessible surrogate for adequate CO). Mental status. CRT. Lactate clearance. ScvO₂ if available. |
| Weaning | Titrate down gradually — abrupt discontinuation of inotropes in HF causes acute decompensation. Reduce by 1–2 mcg/kg/min every 2–4 hours while monitoring hemodynamics. |
NCLEX Pearls
Dobutamine = positive inotrope (contractility ↑). Tachycardia is the main side effect. Does NOT work well with high-dose beta-blockers.
Milrinone = inodilator (contractility ↑ + vasodilation). Works WITH beta-blockers. Major risk = hypotension. Preferred for RV failure + PAH. Renally cleared — reduce dose in CKD.
Epinephrine causes aerobic lactate elevation (beta-2 stimulation → aerobic glycolysis) — does NOT indicate inadequate resuscitation on epinephrine infusion.
Dopamine is a vesicant — extravasation causes necrosis. Give via central line. Antidote for extravasation: phentolamine SC.
Digoxin: hold if HR < 60. Toxicity = nausea + yellow-green visual halos + arrhythmias. Hypokalemia potentiates. Antidote = Digibind.
SOAP II trial: norepinephrine superior to dopamine for septic shock (fewer arrhythmias). Dopamine is second-line for septic shock.
Related Resources
Vasopressors & Inotropes GuideNorepinephrine, vasopressin, phenylephrine — vasopressor coverage
Open →Tissue Perfusion Assessment GuideMonitoring markers used to assess response to inotrope therapy
Open →Hemodynamic Monitoring Basics GuideCO, CI, SVR, MAP — hemodynamic parameters that guide inotrope titration
Open →Standards & sources
Fact-checked Jun 20, 2026This page is written to align with Society of Critical Care Medicine (SCCM) · Surviving Sepsis Campaign · American Association of Critical-Care Nurses (AACN). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →