What is the treatment for a nortriptyline (tricyclic antidepressant) overdose?

From the Guidelines

Treatment of nortriptyline overdose requires immediate medical attention, with a focus on supportive care, gastrointestinal decontamination, and management of complications, prioritizing sodium bicarbonate administration to treat cardiotoxicity, as recommended by the 2020 American Heart Association guidelines 1. The primary goal is to stabilize the patient's airway, breathing, and circulation.

• Activated charcoal (1 g/kg orally) should be administered if the patient presents within 1-2 hours of ingestion and has a protected airway.
• Gastric lavage may be considered for large ingestions if performed early.
• Sodium bicarbonate (1-2 mEq/kg IV bolus, followed by infusion) is crucial in treating cardiotoxicity by alkalinizing the blood to a pH of 7.45-7.55, which reduces tricyclic binding to cardiac sodium channels 1.
• Benzodiazepines like diazepam (5-10 mg IV) or lorazepam (2-4 mg IV) should be given for seizures.
• Hypotension can be treated with IV fluids and, if necessary, vasopressors like norepinephrine.
• Cardiac monitoring is essential as nortriptyline can cause QRS prolongation, QT prolongation, and arrhythmias.
• Physostigmine is generally avoided due to the risk of seizures and asystole.
• Hemodialysis is ineffective due to nortriptyline's high protein binding.
• Treatment should continue until cardiac conduction normalizes and anticholinergic symptoms resolve, which may take 24-48 hours due to nortriptyline's long half-life. It is also important to note that while magnesium and lipid emulsion therapy have been studied, there is limited evidence to support their use in TCA-induced hypotension, acidosis, and/or QRS prolongation 1. Prompt consultation with a medical toxicologist or other specialist with up-to-date knowledge is strongly recommended for optimal management 1.

From the FDA Drug Label

OVERDOSAGE Deaths may occur from overdosage with this class of drugs. Multiple drug ingestion (including alcohol) is common in deliberate tricyclic antidepressant overdose. As the management is complex and changing, it is recommended that the physician contact a poison control center for current information on treatment Management General Obtain an ECG and immediately initiate cardiac monitoring Protect the patient's airway, establish an intravenous line and initiate gastric decontamination. Gastrointestinal Decontamination All patients suspected of tricyclic antidepressant overdose should receive gastrointestinal decontamination. This should include large volume gastric lavage followed by activated charcoal. Cardiovascular A maximal limb-lead QRS duration of ≥ 0. 10 seconds may be the best indication of the severity of the overdose. Intravenous sodium bicarbonate should be used to maintain the serum pH in the range of 7.45 to 7.55. CNS In patients with CNS depression, early intubation is advised because of the potential for abrupt deterioration. Seizures should be controlled with benzodiazepines, or if these are ineffective, other anticonvulsants (eg, phenobarbital, phenytoin)

The treatment for a nortriptyline overdose includes:

• Gastric decontamination: large volume gastric lavage followed by activated charcoal
• Cardiac monitoring: obtain an ECG and immediately initiate cardiac monitoring
• Airway protection: protect the patient's airway and establish an intravenous line
• Cardiovascular management: use intravenous sodium bicarbonate to maintain serum pH, and consider lidocaine, bretylium, or phenytoin for dysrhythmias
• CNS management: early intubation for CNS depression, and control seizures with benzodiazepines or other anticonvulsants 2

From the Research

Treatment for Nortriptyline Overdose

The treatment for a nortriptyline overdose involves several key components, including:

• Supportive care to manage symptoms and prevent further complications
• Gastric decontamination using activated charcoal and/or gastric lavage 3, 4
• Administration of sodium bicarbonate to help manage cardiac arrhythmias and widenings of the QRS interval 5, 6, 3, 4
• Use of magnesium sulfate and vasopressors as needed to manage hypotension and other cardiovascular symptoms 6
• Monitoring of electrocardiogram (ECG) and QT interval to assess for cardiotoxicity 5, 6, 3

Management of Cardiac Complications

Cardiac complications, such as ventricular arrhythmias and widened QRS intervals, are a major concern in nortriptyline overdose. Treatment options include:

• Sodium bicarbonate infusion to help narrow the QRS interval and manage arrhythmias 5, 3
• Hypertonic saline as a potential alternative to sodium bicarbonate 3
• Monitoring of ECG and QT interval to assess for cardiotoxicity 5, 6, 3

Role of Quantitative Serum Nortriptyline Levels

Quantitative serum nortriptyline levels can be useful in guiding treatment, particularly in cases of massive overdose. However, the pharmacokinetics of nortriptyline can be unpredictable at toxic levels, and routine pharmacokinetic values may not be reliable 5. Urine TCA screens can also provide useful information to guide therapy 5.