Shock and vasoactive support

Inotropes and inodilators

Reviewed Nov 2026·3 references
New· views rounded down, updated weekly

Use an inotrope only when low cardiac output causes hypoperfusion despite adequate filling and MAP. Dobutamine is the usual first choice; milrinone or levosimendan suit beta-blocked or RV-failure patients.

At the bedside

Timed steps
  1. 1

    Low output is the problem

    Confirm

    Echo: poor LV or RV function, low LVOT VTI (< 15 cm suggests low stroke volume), cold periphery, low ScvO2 (< 65-70%), raised lactate with adequate MAP and filling.

  2. 2

    MAP first

    Prepare

    Inotropes vasodilate: secure MAP ≥ 65 with noradrenaline before or with the inotrope.

  3. 3

    Dobutamine

    Start

    2.5 mcg/kg/min, increase every 10-15 min by 2.5 to 5-10 mcg/kg/min.

  4. 4

    Milrinone or levosimendan

    Alternatives

    Beta-blocked patient, pulmonary hypertension or RV failure: milrinone 0.125-0.5 mcg/kg/min (no bolus); levosimendan 0.05-0.2 mcg/kg/min for 24 h.

  5. 5

    Response

    Monitor

    Lactate, ScvO2, urine output, VTI/CO, arrhythmias. Stop if tachyarrhythmia or no improvement in 1-2 h.

  6. 6

    Early

    Wean

    Inotropes increase myocardial O2 use and arrhythmias: use the lowest effective dose for the shortest time.

First-line inotrope

Dobutamine

IV infusion
Dose
2.5-10 mcg/kg/min (max 20)
Range
2.5–20 mcg/kg/min
Preparation
250 mg in 50 mL = 5000 mcg/mL
Worked example
60 kg × 5 mcg/kg/min = 300 mcg/min × 60 = 18 000 mcg/h ÷ 5000 = 3.6 mL/h
Open infusion calculator

Inodilator (RV failure, high PVR, beta-blocked)

Milrinone

IV infusion
Dose
0.125-0.5 mcg/kg/min (max 0.75); omit bolus
Range
0.125–0.75 mcg/kg/min
Preparation
10 mg in 50 mL = 200 mcg/mL
Worked example
70 kg × 0.25 = 17.5 mcg/min × 60 = 1050 mcg/h ÷ 200 = 5.25 mL/h

Halve or reduce dose in AKI.

Open infusion calculator

Inodilator (beta-blocked, decompensated HF)

Levosimendan

IV infusion over 24 h
Dose
0.05-0.2 mcg/kg/min; no bolus if SBP < 100
Preparation
12.5 mg in 500 mL D5 = 25 mcg/mL
Worked example
70 kg × 0.1 = 7 mcg/min × 60 = 420 mcg/h ÷ 25 = 16.8 mL/h
Open infusion calculator
Red flag · call your senior now
New tachyarrhythmia on dobutamine: reduce or stop.
Red flag
Hypotension after starting milrinone: increase noradrenaline, reconsider.
Pitfall
Starting an inotrope in hypovolaemic or vasodilatory shock with a hyperdynamic heart.
Pitfall
Inotropes in LVOT obstruction (SAM, HOCM) worsen obstruction: give fluid, beta-blocker and phenylephrine instead.
Pearl
Septic cardiomyopathy: SSC 2026 suggests adding dobutamine to noradrenaline, or using adrenaline alone, if hypoperfusion persists despite adequate volume and MAP. It suggests against levosimendan in septic shock.

Calculators for this topic

Infusion rate from mcg/kg/min

Pump rate in mL/h for drugs dosed in mcg/kg/min (noradrenaline, adrenaline, dobutamine, milrinone, nitroglycerin by weight).

References

  1. 1

    McDonagh TA, Metra M, Adamo M, et al. 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. Eur Heart J. 2021;42(36):3599-3726

  2. 2

    Mathew R, Di Santo P, Jung RG, et al. Milrinone as compared with dobutamine in the treatment of cardiogenic shock (DOREMI). N Engl J Med. 2021;385(6):516-525

  3. 3

    Prescott HC, Antonelli M, Alhazzani W, et al. Surviving Sepsis Campaign: international guidelines for management of sepsis and septic shock 2026. Intensive Care Med. 2026;52(5):863-936. Co-published in Crit Care Med. 2026 (doi:10.1097/CCM.0000000000007075)

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Educational reference for trained clinicians. Check doses against your hospital protocol and the patient in front of you.