Toxicology
iii.
May consider a continuous infusion of hypertonic saline in patients with refractory cardiac
conduction despite optimal serum alkalinization by increasing sodium load.
Proposed indications for sodium bicarbonate include the following (Chest 2008;133:1006-13;
Circulation 2023;148:e149-84):
QRS greater than 100–120 milliseconds
ii.
Wide complex tachycardia
iii.
Cardiac arrest
iv.
Right bundle-branch block
Refractory hypotension
| d. | Replace serum electrolytes, especially magnesium and potassium, if QT prolongation is present. |
|---|
Magnesium replacement is recommended for membrane stabilization in patients with a QTc greater
than 500 milliseconds and normal serum magnesium concentrations.
Seizures should be managed with benzodiazepines. Phenobarbital and propofol may be considered
if the patient is refractory to benzodiazepines and has a stable BP.
Phenytoin and lacosamide are not recommended because of their effects on sodium channels
and cardiac adverse effects, respectively.
Intravenous fat emulsion
Many case reports for use in amitriptyline and SSRI overdose
ii.
Administration (use lean body mass):
| (a) | Bolus of 1.5 mL/kg of 20% lipid emulsion (Intralipid) over 1–5 minutes (typical dose is |
|---|
usually 100 mL for patients weighing 70 kg and more)
| (b) | May repeat up to two times for persistent cardiovascular collapse |
|---|---|
| (c) | Bolus doses should be followed by an intravenous infusion of 0.25–0.5 mL/kg/minute for |
60 minutes (typical dose is 18 mL/minute for a 70 kg patient)
| (d) | Continue for up to 10 minutes after cardiovascular recovery. |
|---|
of 24 hours for more severe adverse effects or with citalopram or escitalopram (because of the longer half-
lives of these agents).
Monitor for cardiac toxicity with a 12-lead ECG, CK-MB, troponins, BP, and HR.
Monitor for signs and symptoms of respiratory depression with RR and pulse oximetry.
Excessive serotonin concentrations lead to overstimulation of serotonin-1A and serotonin-2A receptors
in the central and peripheral nervous systems (Emerg Med Clin North Am 2007;25:477-97).
hypertension, arrhythmias), and neuromuscular changes (hyperreflexia, increased rigidity).
Diagnosis is made according to clinical findings; many clinicians support the use of the Hunter Serotonin
Toxicity Criteria (QJM 2003;96:635-42). By this method, patients are likely to have serotonin toxicity if
they have taken a serotonergic agent and one of the following criteria are present:
Spontaneous clonus
Inducible clonus PLUS agitation or diaphoresis
Ocular clonus PLUS agitation or diaphoresis
| d. | Tremor PLUS hyperreflexia |
|---|
Hypertonia PLUS temperature above 100.4°F (38°C) PLUS ocular clonus or inducible clonus
Treatment should focus on supportive care with intravenous fluids; symptoms typically resolve within
24–48 hours.
Discontinue the offending agent.
Benzodiazepines should be administered as first line for agitation and muscle rigidity.