HPLC/MS findings in a fatality involving sustained-release verapamil

A fatality involving verapamil, a calcium channel blocker agent, is presented. A 51-year old male ingested 7200 mg of sustained-release (SR) verapamil at T0 and died 40 hours later of refractory, mixed shock and multiorgan failure. The symptoms displayed during hospitalization were quite typical and involved altered consciousness, hypotension, bradycardia, atrioventricular block, metabolic acidosis and renal failure. Verapamil and its primary metabolite, norverapamil, were assayed on eight plasma and two urine samples, successively taken between the admission to the ICU (T0-4 hours) and time of death, using an original high-performance liquid chromatography/mass spectrometry (HPLC/MS) procedure with verapamil-d3 as internal standard. Plasma verapamil and norverapamil levels on admission were 0.94 and 1.36 mg/mL, respectively, then verapamil remained practically unchanged throughout the hospitalization (0.85 mg/mL at T0-40 hours). The discussion focuses on the detrimental role of SR formulations in overdose, with special emphasis on the risk of pharmacobezoar development already reported with SR-verapamil. To our knowledge, this is the first report of a verapamil fatality documented by repeated plasma measurements of the drug during the antemortem period.

Fatality after deliberate ingestion of sustained-release ibuprofen: a case report

INTRODUCTION

Ibuprofen is a nonsteroidal anti-inflammatory drug available over the counter and on prescription for the management of pain and inflammation. Severe toxicity is rare following deliberate self-poisoning with ibuprofen, and patients are usually either asymptomatic or develop only mild gastrointestinal toxicity. Although there have been nine other reported fatalities, co-existent factors have probably contributed to all of these deaths. We report here a fatality from isolated toxicity following self-poisoning with sustained-release ibuprofen.

CASE REPORT

A 26-year-old female presented after deliberate ingestion of up to 105 g sustained-release ibuprofen, with a reduced level of consciousness, severe metabolic acidosis and haemodynamic compromise. Despite intensive supportive management, gut decontamination with multidose activated charcoal and correction of the metabolic acidosis with sodium bicarbonate and haemofiltration, the patient did not survive. The ibuprofen concentration ante mortem on presentation in peripheral blood was 760 mg/l and the concentrations post mortem were 518 mg/l in peripheral blood, 74 mg/kg in liver extract and 116 mg/l in the gastric contents.

DISCUSSION

Most patients with ibuprofen poisoning are either asymptomatic or have mild gastrointestinal symptoms; severe poisoning with ibuprofen is rare. We report the first death related to isolated sustained-release ibuprofen poisoning.

Continuous venovenous hemodiafiltration to treat controlled-release carbamazepine overdose in a pediatric patient

Carbamazepine (CBZ) intoxication is an important issue in acute poisoning practice. Highly protein-bound, CBZ is not removed efficiently through conventional hemodialysis. We describe the use of continuous venovenous hemodiafiltration (CVVHDF) in a 2-year-old boy who developed general tonic clonic seizure and respiratory depression due to controlled-release formula of CBZ overdose (peak drug level of > 20 microg.ml(-1), therapeutic range: 5-10 microg.ml(-1)). Serum CBZ concentrations fell to 0.25 microg.ml(-1) at the end of hemodiafiltration. The patient recovered rapidly and was discharged from hospital 4 days from the time of ingestion with no complications or neurologic impairment.

Prolonged clinical effects in modified-release amitriptyline poisoning

BACKGROUND

Tricyclic antidepressant poisoning is often associated with significant cardiovascular and central nervous system toxicity. Effective treatment includes the use of appropriate gastric decontamination techniques, the administration of sodium bicarbonate, and meticulous supportive care. Tricylcic antidepressant toxicity typically lasts 24-48 hours following a significant overdose.

CASE REPORT

We describe a case of tricyclic antidepressant poisoning where significant clinical toxicity (QRS prolongation, metabolic acidosis) was observed for up to 4 days following ingestion of a modified-release preparation of amitriptyline. Successful patient recovery was associated with the use of multidose activated charcoal and repeated administration of intravenous sodium bicarbonate.

CONCLUSIONS

Clinicians should be aware of the potential for prolonged tricyclic toxicity in patients who have ingested modified-release amitriptyline in overdose. Gastric decontamination techniques such as multidose activated charcoal and whole bowel irrigation should be considered where there is evidence of ongoing tricyclic antidepressant absorption or clinical toxicity following ingestion of a modified-release preparation. These interventions may be indicated for prolonged periods (greater than 36 hours) post ingestion.

Delayed poisoning emergencies

The American Association of Poison Control Centers (PCCs) has a nationwide toll-free number for contacting regional poison centers. To be automatically connected to a local poison center, call 800/222-1222. EMS providers should follow local protocols to determine how to contact PCCs, either directly or through on-line medical control. Most experts agree that PCCs are a reliable and current source of information on the assessment and treatment of poisoning emergencies.

[Aetiologies of lithium overdose: 10-year experience of Marseille poison centre]

OBJECTIVE

Lithium is used for control of bipolar disorders. In order to precise the different circumstances at the origin of poisonings, the authors present the cases of lithium intoxication observed in the Marseille poison centre between January 1991 and December 2000.

STUDY DESIGN

Retrospective study.

METHODS

Three hundred and four cases were observed during the studied period (1 patient a case), concerning 6 different circumstances. For 3 of them, the symptoms were mild: accidental ingestion with children (13 cases); mistakes on the quantities of ingested tablets (43 cases); elevation of lithium blood level due to diuretic therapy (8 cases). For 2 other circumstances, the clinical signs were more severe: treated patients who developed renal failure (15 cases, 6 patients managed in intensive care unit [ICU], 1 death) or dehydration (35 cases, 8 patients treated in ICU and 1 death). Finally, the most severe cases were collected with suicide attempts. Fifty-six percent of the patients were managed in ICU, 5% needed haemodialysis, 10% had cardiac (repolarization disturbances) or neurological (seizures) complications, 2% died.

CONCLUSION

The severity of lithium poisonings depends of the circumstances. Ingestion of high quantities of sustained released tablets is the most dangerous situation. Accidental ingestion, even with children, must be considered as less severe situations.

Oxycontin: the concept of a "ghost pill" and the postmortem tissue distribution of oxycodone in 36 cases

Oxycodone is a semi-synthetic opioid that is structurally similar to codeine and equipotent to morphine in producing analgesic effects. Oxycodone has been prescribed in many immediate-release formulations including Percodan, Percocet, Tylox, Roxicodone, and Toxicet. In 1995, the Food and Drug Administration approved Oxycontin, a controlled-release form of oxycodone. Although the immediate-release forms of oxycodone can be prescribed in doses of 10-30 mg every 4 h, it is recommended that Oxycontin be prescribed in doses of 10-160 mg every 12 h. In a six-year period, the Los Angeles County Department of Coroner's Toxicology Laboratory detected oxycodone in 67 cases, 36 of which were determined to be the controlled-release form. The objectives of this paper are to provide general information about Oxycontin, including postmortem tissue distributions of oxycodone in cases in which the controlled-release form was identified, and to introduce the concept of ghost pills. A ghost pill is a seemingly intact but drug-free tablet that resembles an undigested pill. The isolation and identification of oxycodone from postmortem specimens was achieved using a basic, liquid-liquid extraction with screening and quantitation by gas chromatography-nitrogen-phosphorus detection and gas chromatography-mass spectrometry, respectively. Oxycodone-d3 was used as an internal standard for quantitation. The assays were linear from 0.10 to 5.0 mg/L. The tissue distribution ranges of oxycodone in the 36 case examples were heart blood 0.12-46 mg/L (36), femoral blood + < 0.10-13 mg/L (35), liver 0.11-6.1 mg/kg (16), urine 2.5-122 mg/L (22), bile 0.19-49 mg/L (15), vitreous 0.24-0.82 mg/L (6), and gastric 0.06-119 mg total (21).

Massive overdose with controlled-release carbamazepine resulting in delayed peak serum concentrations and life-threatening toxicity

INTRODUCTION

Peak serum levels following overdose with immediate-release formulations of carbamazepine have been reported to occur up to 2 days postingestion. We report a case of poisoning with carbamazepine controlled-release resulting in peak levels 96 h postingestion.

CASE REPORTS

A 31-year-old female presented following a suspected polypharmacy overdose. She was haemodynamically stable with a Glasgow Coma Scale score of 3 and was endotracheally intubated in the emergency department. A single-dose of activated charcoal was administered on admission and her neurological status improved gradually Results of qualitative urine drug screen available 24 h postadmission to the intensive care department revealed benzodiazepines and carbamazepine. The serum carbamazepine concentration at this time was 66 micromol/L (therapeutic 17-42 micromol/L). A history of therapy with controlled-release carbamazepine was discovered. Repeat-dose activated charcoal and whole-bowel irrigation were commenced, but poorly tolerated. Serum carbamazepine levels continued to rise and gastrointestinal tract decontamination was ceased due to the presence of an ileus. By day 4, the serum carbamazepine concentration peaked at 196 micromol/L. This was associated with coma, generalized intermittent seizure activity and hypotension. Charcoal haemoperfusion was commenced due the presence of end-organ toxicity and failed gastrointestinal tract decontamination. Serum carbamazepine concentrations fell from 176 to 106 micromol/L after 1 h of haemoperfusion and the patient was rousable to voice and could obey commands at this time. She confirmed ingestion of 300 Tegretol-CR (200 mg) on extubation and was discharged without long-term sequelae.

CONCLUSION

Unrecognized poisoning with controlled-release carbamazepine has the potential to produce significant delayed carbamazepine toxicity and delayed peak serum carbamazepine concentrations. This may occur much later than previously reported with immediate-release carbamazepine preparations.

Sustained-release bupropion overdose: a new entity for Australian emergency departments

Bupropion hydrochloride (Zyban, Glaxo Wellcome Australia, Melbourne, Vic., Australia) was released in Australia in November 2000 as adjunctive therapy to assist with smoking cessation, having previously been used as an antidepressant in the US since 1989. The toxicity profile of bupropion hydrochloride in overdose differs considerably from other antidepressants, with prominent neurological manifestations and little cardiovascular toxicity. A case of bupropion overdose demonstrating the typical toxic syndrome is presented, together with a review of the literature and a discussion of the magnitude of the demand for bupropion and of the potential differences in presentation of overdoses in Australia.

Late increase in acetaminophen concentration after overdose of Tylenol Extended Relief

We report a case demonstrating a late increase in acetaminophen concentration after ingestion of Tylenol Extended Relief (extended-release acetaminophen; McNeil Consumer Products) along with drugs known to slow gastrointestinal motility. Coingestants that slow gastrointestinal motility are known to affect the interpretation of serum drug concentrations. However, this case illustrates potentially significant differences between extended-release and immediate-release acetaminophen and demonstrates an exception to the current manufacturer recommendation for the use of the Rumack-Matthew nomogram in this setting.

Controlled release drugs in overdose. Clinical considerations

The main characteristic of overdose with controlled release formulations is the delay in presentation and onset of clinical effects. There is a prolonged absorption phase which leads to a delayed time to maximum plasma concentration and usually a prolonged time with levels close to the peak concentration. Absorption may continue for more than 24 hours. Overdose with controlled release formulations of toxic drugs therefore requires a longer period of observation as the onset of symptoms may be as late as 16 to 20 hours after ingestion. Treatment nomograms calculated for standard formulations are not appropriate for controlled release formulations. The optimal gastrointestinal decontamination method is controversial, but in serious overdoses it should include gastric lavage and activated charcoal followed by whole bowel irrigation as a means of clearing whole tablets from the gastrointestinal tract. Pharmacobezoar formation should be suspected if, despite apparently effective gastrointestinal decontamination, there is evidence of continuing absorption. These are best diagnosed with endoscopy and the treatment options include endoscopic removal, whole bowel irrigation and surgery.

Whole-bowel irrigation versus activated charcoal in sorbitol for the ingestion of modified-release pharmaceuticals

Overdose with modified-release pharmaceuticals is an increasing phenomenon. This study examines whole-bowel irrigation as a potential decontamination strategy after overdose with enteric-coated acetylsalicylic acid and compares it with administration of activated charcoal in sorbitol, which is currently the recommended intervention. A three-phase randomized crossover protocol was used in 10 adult volunteers. Each volunteer ingested nine 325 mg doses of enteric-coated acetylsalicylic acid on three occasions, with at least 1 week between each administration period. Serum samples were analyzed for salicylic acid concentration by HPLC. Both interventions decreased peak salicylic acid concentration, time-to-zero salicylic acid concentration, and AUC when compared with control (p less than 0.01). Whole-bowel irrigation was superior to activated charcoal in sorbitol by all three criteria (p less than 0.05). Adverse effects were qualitatively and quantitatively greater during activated charcoal in sorbitol, and the volunteers preferred whole-bowel irrigation over charcoal in sorbitol. Our data suggest that whole-bowel irrigation should be considered for overdose of other modified-release pharmaceuticals.

[Fatal poisoning by the retard form of verapamil. Therapeutic considerations]

A 60-year-old woman swallowed 2.4 g verapamil in a retard form (Isoptin retard). Depsite intensive efforts she died 44 hours later in a coma due to circulatory collapse. In contrast to other reported cases of poisoning, the verapamil concentration in plasma continued to rise. This atypical course with continuing absorption of verapamil was due to small-intestinal deposits of the drug, found at autopsy.

Fatal overdose from Bendectin

A three-year old male ingested approximately 100 tablets of Bendectin. He developed tonic-clonic seizures followed by cardiac arrest. Toxicologic analysis yielded high levels of doxylamine, dicyclomine, and pyridoxine in blood, peritoneal fluid, and tissue homogenates. The antihistamine, doxylamine succinate appears to be the toxic constituent. Analytical methods used to document the case are herein described.