Venlafaxine/lorazepam overdose

Reactions 1444 - 23 Mar 2013

(67 beats/min) and a QRS duration of 129 msec. She becamecomatose, with low cardiac output (1 L/min), and died from O SVenlafaxine/lorazepam overdose refractory cardiogenic shock 14h after admission.

Author comment: "Acute heart failure followingAcute heart failure and various other toxicities:venlafaxine overdose may be due to several4 case reportspathophysiological mechanisms."Four patients developed acute heart failure and various

other toxicities following an overdose of venlafaxine, with or Batista M, et al. The spectrum of acute heart failure after venlafaxine overdose.without lorazepam. Clinical Toxicology 51: 92-95, No. 2, Feb 2013. Available from: URL: http://

dx.doi.org/10.3109/15563650.2012.763133 - Belgium 803084586A 38-year-old woman with depression ingested an overdoseof extended-release venlafaxine 4200mg together withbenzodiazepines and ethanol. She was found about 6h laterwith a Glasgow Coma Scale (GCS) score of 9/15, BP of70/40mm Hg and HR of 106 beats/min. Upon admission, anECG showed sinus rhythm, diffuse and aspecific ST changes,and a QTc interval of 449 msec. Despite treatment withdobutamine, epinephrine [adrenaline] and norepinephrine[noradrenaline], she developed acute renal failure requiringcontinuous venovenous haemofiltration, rhabdomyolysis(peak CK 3479 IU/L), ischaemic liver injury and cytolysis. Herpeak troponin I level 40h post-ingestion was 22.49 ng/mL. Shehad a peak venlafaxine serum concentration of 2153.3 ng/mLand an O-desmethylvenlafaxine (ODV) concentration of960.1 ng/mL. An echocardiogram revealed global alteration ofleft ventricular (LV) contractility, with a LV ejection fraction(LVEF) of 16%. She also had ventricular tachycardia and atrialfibrillation. On day 3, she developed Streptococcuspneumoniae septicaemia and pneumonia leading to acuterespiratory distress syndrome. Her LVEF increased to 59% onhospital day 10, but she died the following day from refractoryhypoxaemia.

A 46-year-old woman was hospitalised 7h after ingesting anoverdose of immediate-release venlafaxine 3150mg andextended-release venlafaxine 2100mg. Her ECG showed sinustachycardia (53 beats/min) and a QTC interval of 447 msec.hours after admission, she developed a tonic-clonic seizurewith hypotension, oliguria and a lactate level of 2.4 mmol/L.She had a LVEF of 18% and her troponin I level was belowreference values. Following administration of insulin, her urineoutput increased and her lactate level decreased. On day 2,she had a peak CK level of 1173 IU/L. Her peak venlafaxine andODV concentrations were 3221 and 2783.4 ng/mL 24h post-ingestion. Her LVEF increased to 65% on day 3 and she made acomplete recovery.

A 35-year-old woman with a history of cocaine addictionwas hospitalised 7h after ingesting 90 tablets of extended-release venlafaxine 150mg. She experienced generalised tonic-clonic seizures upon admission, and was treated withdiazepam and midazolam. Her BP was 80/60mm Hg and herHR was 134 beats/min. Other symptoms included confusion,agitation, visual hallucinations, tremor of the extremities and abilateral horizontal nystagmus. At 10h post-ingestion, shedeveloped a generalised tonic-clonic status epilepticus whichdid not respond to phenytoin and benzodiazepines. Her LVEFwas 15%, and an ECG showed sinus rhythm (153 beats/min), aQRS duration of 133 msec and a QTc interval of 529 msec,with atrial fibrillation. Despite treatment with dobutamine andmilrinone, she remained hypotensive and anuric. Oxygenvenous saturation in the superior vena cava was 46% and herPaO2/FiO2 ratio was <100mm Hg. Recurrent hypoglycaemiawas treated with hypertonic glucose. At 17h post-ingestion,laboratory investigations included the following: lactate9.4 mmol/L, troponin I 4.1 ng/mL, CK 2968 IU/L and INR 3.2.Her temperature increased to 39.3°C, and she died from asudden cardiac arrest 24h post-ingestion.

A 65-year-old woman was hospitalised more than 12h afteringesting an overdose of immediate-release venlafaxine7000mg and lorazepam 40mg. She had a GCS score of 14/15,with the following vital signs: temperature 36.2°C, respiratoryrate 14 breaths/min, HR 105 beats/min, BP 50/40mm Hg andoxygen saturation 92%. An ECG showed sinus rhythm and aQRS duration of 116 msec. Laboratory investigations includedthe following: lactate 3.71 mmol/L, creatinine 2.14 mg/dL andCK 90 IU/L. Her serum venlafaxine concentration was9950 ng/mL. A repeat ECG showed an idioventricular rhythm

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