Wide-complex TCA — lipid and the flumazenil trap

Keep alkalinising. Bicarbonate combined with mechanical ventilation reached the target pH of 7.45–7.55 more often than single or supportive therapy and narrowed the QRS twice as quickly.^[10] If hypotension persists despite adequate filling pressure and bicarbonate, inotropic support is started; norepinephrine appeared more effective than dopamine in an uncontrolled study.^[7]

Adjuncts. Lidocaine has been reported as effective adjunctive therapy in severe cardiotoxicity, with less convincing evidence for phenytoin.^[9]

Lipid emulsion. For life-threatening amitriptyline toxicity, the lipid workgroup suggests not using intravenous lipid emulsion first-line but suggests it if other therapies fail; the panel was neutral on dosing and infusion duration for non-local-anaesthetic toxins because of insufficient data.^[6] In published neuropsychiatric drug case reports, haemodynamic depression intractable to supportive treatment was the main reason lipid was given (88.3 per cent of cases).^[5]

Flumazenil. Flumazenil is not recommended for tricyclic poisoning, and seizures can occur with flumazenil after a combined tricyclic and benzodiazepine overdose.^[3][8]