Dobutamine
Dobutamin Hameln
Pure inotropy when the problem is the pump and not vascular tone. Strong β₁ effect with marked β₂ effect means that stroke volume increases while systemic vascular resistance falls at low doses — good in the cold, hypoperfused patient with an acceptable blood pressure, less so when blood pressure is already low. The dose threshold lies around 5 μg/kg/min: below that vasodilation predominates, above it the vascular effect shifts toward constriction.
Dobutamine increases myocardial oxygen consumption and can precipitate ischaemia, tachyarrhythmia, and rapid ventricular rate in atrial fibrillation. Never given without continuous ECG and blood pressure monitoring, and not to a patient with uncorrected hypovolaemia.
Dosing in adults
| Indication | Regimen | Comment |
|---|---|---|
| Cardiogenic shock and low cardiac output | 2–20 μg/kg/min iv, titrate in steps of 2–3 μg/kg/min | below 5 μg/kg/min vasodilation; above 5 μg/kg/min vasoconstriction |
| Acute decompensated heart failure with hypoperfusion | 2,5–10 μg/kg/min iv | shortest possible treatment duration, no prognostic benefit |
| Stress echocardiography | Start 5 μg/kg/min, increase every 3 minutes to 10, 20, 30 and 40 μg/kg/min | atropine may be needed to achieve the target heart rate |
| Bradycardia (second-line) | 2–10 μg/kg/min iv | after atropine and while awaiting pacing |
| Maximum dose | 40 μg/kg/min | arrhythmia and ischaemia are limiting factors far below this level |
No dose adjustment. Metabolites are inactive and accumulation has no clinical significance.
No established dose adjustment. Titrate to effect.
2–20 μg/kg/min; children likely tolerate a lower maximum dose than adults, titrate cautiously.
The effect is absent in a patient on non-selective beta-blockade — do not increase the dose in that situation, switch to an inotropic agent acting downstream of the beta receptor, such as levosimendan or milrinone. Also avoid in hypertrophic obstructive cardiomyopathy and in severe hypovolaemia, where increased contractility worsens the outflow obstruction or drains an already underfilled ventricle.
Pharmacokinetics
- BIOAVAIL.
- Intravenous only
- ONSET
- 1–2 minutes
- PEAK EFFECT
- 10–12 minutes
- t½
- 2 minutes
- Vd
- 0,2 l/kg
- METABOLISM
- COMT to 3-O-methyldobutamine (inactive)
- EXCRETION
- Renal as conjugates
- TOLERANCE
- Receptor downregulation after 2–3 days