Toxic Agents and Antidotes
Overdose in the Night: A Deadly Encounter with Imipramine
Omid Mehrpour
Post on 14 Mar 2025 . 5 min read.
A Critical Case of Imipramine Overdose: A Life Hanging by a Thread
It was just past midnight when a twenty-five-year-old woman was rushed into the emergency department. Her vital signs were unstable, her body was failing, and her life was hanging by a thread. She had ingested up to seventy-two tablets of Imipramine, a powerful tricyclic antidepressant, and no one knew exactly when it had happened.
By the time she arrived at midnight, she was already in a critical condition—her heart was beating irregularly, she was unconscious, and her body was beginning to shut down. What followed was a desperate medical battle against a deadly Imipramine overdose, cardiac arrhythmias, seizures, and severe metabolic acidosis.
The Imipramine Overdose and the Immediate Crisis
Imipramine, a medication once widely used for depression, has a dangerous side when taken in excessive amounts. It affects the heart, brain, and multiple organ systems. In this case, it had already pushed the young woman into a state of wide-complex tachycardia, a dangerous form of irregular heart rhythm seen in Imipramine overdose ECG findings.
Upon arrival at the hospital:
She was immediately intubated to protect her airway and ensure she could breathe properly.
She was sedated with Propofol and Fentanyl to keep her calm and prevent agitation.
She suffered a life-threatening heart rhythm disturbance known as torsades de pointes three times.
She received thirteen doses of sodium bicarbonate, a key part of Imipramine overdose treatment, to counteract severe metabolic acidosis in her bloodstream.
Lidocaine was considered as a possible treatment to stabilize her heart rhythm.
A discussion occurred about using extracorporeal membrane oxygenation, a machine that temporarily replaces heart and lung function in life-threatening cases.
Despite these aggressive treatments, her blood pH had dropped below 7.0, indicating life-threatening acidity, and her lactate level had risen to 12.0 mmol/L, a sign of severe shock and poor oxygen delivery to her organs.
The Toxicity of Imipramine: A Chemical War on the Body
How long does Imipramine stay in your system? The half-life of Imipramine varies between 9 to 20 hours, but in cases of overdose, it can take much longer to be eliminated due to its toxic effects on the liver and kidneys.
Imipramine poisoning is extremely dangerous because it:
Blocks sodium channels in the heart, leading to a dangerously widened QRS complex and life-threatening arrhythmias, often detected in an Imipramine overdose ECG.
Lowers the seizure threshold, significantly increasing the risk of dangerous convulsions.
Causes severe metabolic acidosis, making the blood dangerously acidic and impairing vital functions.
Triggers extreme low blood pressure and circulatory shock, requiring medications like Levosimendan and Norepinephrine to keep her blood pressure stable.
With no exact ingestion time known, the doctors had to assume the worst-case scenario and act with the most aggressive overdose of Imipramine treatments available.
A Desperate Medical Battle: Fighting to Keep Her Alive
As her condition continued to worsen, the medical team worked tirelessly:
Magnesium and potassium were aggressively replaced to prevent further heart rhythm disturbances.
A continuous infusion of sodium bicarbonate, an essential Imipramine overdose treatment, was started despite concerns about an increasing sodium level in her blood.
Lidocaine was suggested to counteract the toxic effects of Imipramine on the heart.
Continuous brain monitoring was initiated after she suffered a seizure.
A special heart-lung machine was kept on standby in case her heart completely failed.
By three o’clock in the morning, her condition remained critical:
Her QRS complex remained dangerously wide at 140 milliseconds, increasing the risk of cardiac arrest.
Her potassium level had dropped to 2.6 mEq/L, a dangerously low level that could worsen her irregular heart rhythms.
Her blood pressure was barely holding at 128/61 mmHg.
Related blog: How Much Bupropion Is Toxic? Understanding the Risks of Overdose
A Glimmer of Hope: Stabilization in the Intensive Care Unit
After nearly six hours of intensive treatment, small signs of improvement began to appear:
Her blood pH had improved to 7.53, indicating recovery from severe metabolic acidosis.
Her potassium level was corrected, reducing the risk of life-threatening heart disturbances.
She no longer needed medications to maintain her blood pressure, which suggested that her circulatory system was stabilizing.
Her heart rate had slowed to the 90s, significantly improving from earlier dangerously high rates.
However, challenges remained:
She developed an extremely high sodium level of 160 mEq/L, possibly due to the excessive sodium bicarbonate administered earlier.
She remained intubated and sedated, though she had started showing some minor neurological responses.
Her liver enzymes were rising, raising concerns about whether Imipramine can cause liver damage—either from the overdose itself or from the shock her body had endured.
The Final Hours in Critical Care
By the evening of March 13th, her condition had stabilized further:
Her QRS complex had narrowed to 146 milliseconds, indicating improvement in her heart’s electrical activity.
She had developed a fever of 101°F, possibly due to aspiration pneumonia from vomiting during the overdose.
She was making purposeful movements, a promising sign of neurological recovery.
However, she remained on mechanical ventilation, and concerns about a prolonged QTc interval and residual drug toxicity remained.
Recognizing and Managing Imipramine Toxicity
Can you overdose on Imipramine?
Yes, Imipramine overdose can be fatal, especially at high doses. The Imipramine maximum daily dose is 300 mg per day for adults, but toxic effects can be seen at lower doses in adolescents and the elderly.
Who Needs Medical Attention?
Anyone who intentionally ingested Imipramine
Anyone who took an unknown amount
Anyone experiencing dizziness, tremors, drowsiness, or palpitations
Symptoms of Severe Imipramine Toxicity
Loss of consciousness or unresponsiveness
Seizures
Abnormal heart rhythms (often detected in Imipramine overdose ECG)
Difficulty breathing or slow breathing
Dangerously low blood pressure
Treatment for Severe Imipramine Toxicity
Administering activated charcoal within two hours, ensuring the airway is protected
Immediate medical care, including:
Supporting breathing and circulation
Controlling seizures
Monitoring and correcting abnormal heart rhythms
Stabilizing blood pressure
Considering intravenous lipid therapy for patients with life-threatening cardiac toxicity
Related Blog: Can You Overdose on Seroquel? Symptoms, Treatment, and Safety Guide
Conclusion: A Battle Not Yet Won
Imipramine overdose deaths are a real risk, making early medical intervention crucial. This case demonstrates the lethal nature of tricyclic antidepressant overdoses, the importance of early and aggressive treatment, and the complex management decisions required to save a life.
Tricyclic antidepressant overdoses remain a serious medical emergency, and this case highlights the rapid interventions needed to prevent fatal outcomes.
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