Inotropic support: first-line therapy

Inotropic support is rarely required for poisonings—it may be considered if hypotension persists despite intravenous fluid resuscitation.

True inotropic drugs specifically increase cardiac contractility (eg adrenaline [epinephrine], high-dose insulin euglycaemia therapy [HIET]); however, the term ‘inotropic support’ is commonly also used for vasopressor drugs (eg argipressin [vasopressin], noradrenaline [norepinephrine]) and chronotropic drugs (eg isoprenaline). Throughout this guideline, the term ‘inotropic support’ refers to adrenaline, argipressin (vasopressin), HIET, isoprenaline and noradrenaline.

Bedside echocardiography is useful to determine the relative contributions of negative inotropy and vasodilation to hypotension, and hence guides the decision of whether to treat with a true inotrope or a vasopressor. This is most relevant for poisonings that cause both cardiogenic and vasoplegic shock (eg calcium channel blockers and beta blockers). If possible, seek advice from a clinical toxicologist before starting inotropic support.

Adrenaline is the most commonly used first-line inotrope for poisonings. Noradrenaline is the most commonly used first-line vasopressor for poisonings that cause peripheral vasodilation—see individual monographs for specific advice.

For hypotension refractory to intravenous fluid resuscitation, an intravenous bolus regimen of adrenaline is usually started to assess the patient’s response to inotropic support. Use:

Assess haemodynamic response and switch to an adrenaline infusion when practical. For adults and children, use:

If the inotropic response to adrenaline is inadequate for patients in cardiogenic shock, other inotropes can be used, such as HIET. Seek advice from a clinical toxicologist on whether to add HIET to adrenaline for inotropic support.

If hypotension is refractory to first-line inotropes or HIET, see Treatment for refractory hypotension.

Advice on preparation and dosing of intravenous inotrope infusions, including adrenaline, argipressin (vasopressin), isoprenaline and noradrenaline, is given in Intravenous inotrope infusions (Appendix 11.1).