Pharmacobezoars Described and Demystified
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Clinical Toxicology ISSN: 1556-3650 (Print) 1556-9519 (Online) Journal homepage: https://www.tandfonline.com/loi/ictx20 Pharmacobezoars described and demystified Serge-Emile Simpson To cite this article: Serge-Emile Simpson (2011) Pharmacobezoars described and demystified, Clinical Toxicology, 49:2, 72-89, DOI: 10.3109/15563650.2011.559472 To link to this article: https://doi.org/10.3109/15563650.2011.559472 Published online: 03 Mar 2011. Submit your article to this journal Article views: 641 Citing articles: 25 View citing articles Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=ictx20 Clinical Toxicology (2011) 49, 72–89 Ó 2011 Informa Healthcare USA, Inc. ISSN 1556-3650 print/ISSN 1556-9519 online DOI: 10.3109/15563650.2011.559472 REVIEW Pharmacobezoars described and demystified SERGE-EMILE SIMPSON Albert Einstein Medical Center, Department of Emergency Medicine, Philadelphia 19141, USA Introduction. A bezoar is a concretion of foreign material that forms and persists in the gastrointestinal tract. Bezoars are classified by their material origins. Phytobezoars contain plant material, trichobezoars contain hair, lactobezoars contain milk proteins, and pharmacobezoars contain pharmaceutical products. Tablets, suspensions, and even insoluble drug delivery vehicles can, on rare occasions, and sometimes under specific circumstances, form pharmacobezoars. The goal of this review is to catalog and examine all of the available reports in the English language medical literature that convincingly describe the formation and management of pharmacobezoars. Methods. Articles included in this review were identified by performing searches using the terms ‘‘bezoar,’’ ‘‘pharmacobezoar,’’ and ‘‘concretion’’ in the following databases: OVID MEDLINE, PubMed, and JSTOR. The complete MEDLINE and JSTOR holdings were included in the search without date ranges. The results were limited to English language publications. Articles that described nonmedication bezoars were not included in the review. Articles describing phytobezoars, food bezoars, fecal impactions, illicit drug packet ingestions, enteral feeding material bezoars, and hygroscopic diet aid bezoars were excluded. The bibliographic references within the articles already accumulated were then examined in order to gather additional pharmacobezoar cases. The cases are grouped by pharmaceutical agent that formed the bezoar, and groupings are arranged in alphabetical order. Discussions and conclusions specific to each pharmaceutical agent are included in that agent’s subheading. Discussion. Patterns and themes that emerged in the review of the assembled case reports are reviewed and presented in a more concise format. Conclusion. Pharmacobezoars form under a wide variety of circumstances and in a wide variety of patients. They are difficult to diagnose reliably. Rules for suspecting, diagnosing, and properly managing a pharmacobezoar are highly dependent on the pharmaceutical agent or agents involved. Becoming familiar with the sparse data available on pharmacobezoars and maintaining a high index of suspicion in future clinical encounters may be the best way to improve diagnostic sensitivity and accuracy. Keywords Gut and hepatotoxicity; Organ/tissue specific; Complications of poisoning; GI; Pharmaceuticals; Other; Gastrointestinal decontamination Introduction under specific circumstances, form pharmacobezoars. The goal of this review is to catalog and examine all of the A bezoar is a concretion of foreign material that forms and available reports in the English language medical literature persists in the gastrointestinal (GI) tract. The word that convincingly describe the formation and management ‘‘bezoar’’ is thought to be derived from the Arabic word of pharmacobezoars. ‘‘badzehr’’ or the Persian word ‘‘panzehr,’’ both of which are terms meaning counterpoison.1 Hard, stone-like bezoars Methods occasionally discovered in a stomach of a ruminant animal, such as a cow or a goat, were prized in antiquity as antidotal Articles included in this review were identified by perform- talismans. Bezoars found in humans are classified by their ing searches using the terms ‘‘bezoar,’’ ‘‘pharmacobezoar,’’ material origins. Phytobezoars contain plant material, and ‘‘concretion’’ in the following databases: OVID trichobezoars contain hair, lactobezoars contain milk MEDLINE, PubMed, and JSTOR. The complete MEDLINE proteins, and pharmacobezoars contain pharmaceutical and JSTOR holdings were included in the search without products. Tablets, suspensions, and even insoluble drug date ranges. The results were limited to English language delivery vehicles can, on rare occasions, and sometimes publications. Resulted articles were then screened for appropriate content. Articles that described nonmedication bezoars were not included in the review. Articles describing phytobezoars, food bezoars, or fecal impactions that may Received 1 December 2010; accepted 28 January 2011. have formed under the indirect influence of a drug were Address correspondence to Serge-Emile Simpson, MD, Albert excluded. Articles describing illicit drug packet ingestions Einstein Medical Center, Department of Emergency Medicine, were excluded. Articles describing pure enteral feeding 5501 Old York Road, Philadelphia 19141, USA. E-mail: material bezoars were not included, as these are food [email protected] bezoars despite the fact that feeds may be pharmaceutical 72 Pharmacobezoars described and demystified 73 products. Similarly, articles describing bezoars caused by noted. On laparotomy, the authors discovered ‘‘a large bolus hygroscopic diet aids, such as glucomannan or psyllium of inspissated charcoal in the caecum’’ and evidence of local fiber, were excluded because they are not strictly therapeutic bowel ischemia without perforation. The patient underwent products. Published opinions or letters to the editor that a right hemicolectomy and survived. The authors concluded discussed pharmacobezoars and their management were that the patient’s critical illness and the lack of cathartic included in this review. The articles collected in the manner coadministration with MDAC were causative factors in the described above, however, proved to be an incomplete formation of the bezoar. catalog of eligible literature. The bibliographic references Merriman and Stokes5 reported an unusual case of AC within the articles already accumulated were then examined bezoar-induced SBO. The patient was a teenaged boy with a in order to gather additional pharmacobezoar cases. history of a high gastric reduction 7 months earlier, anorexia nervosa, and severe malnutrition who was being treated for a Activated charcoal combined opiate, benzodiazepine, and tricyclic antidepres- There are a number of case reports that suggest therapeutic sant (TCA) overdose. He was given two 50 g doses of AC, 4 h use of activated charcoal (AC) can generate hard concretions apart, without a cathartic. Within 24 h, the patient developed a in the GI tract. AC bezoars typically cause a mechanical GI bowel obstruction and underwent laparotomy. A 6 cm 6 5cm tract obstruction without systemic toxicity. charcoal bezoar was identified in the mid-jejunum and Watson et al.2 reported an unconfirmed case of intestinal manually fragmented without the need for enterotomy or obstruction caused by AC. The patient was an adult man bowel resection. In comparison to the cases above, this patient being treated for a serious acute overdose of carbamazepine received a small amount of charcoal. The authors suggested and thioridazine. The patient was intubated and started on a that the combined anticholinergic and opiate ingestion, multidose activated charcoal (MDAC) regimen (240 g in the together with the patient’s history of bariatric surgery, perhaps first 24 h) along with repeat doses of magnesium citrate via slowed the transit of the charcoal. nasogastric (NG) tube. Clinical and radiographic signs of The capacity for inspissated AC to cause perforation was bowel obstruction developed within 24 h. Magnesium demonstrated in a case report by Gomez et al.6 The patient citrate cathartics as well as multiple saline enemas was a young woman who underwent MDAC therapy for an encouraged the patient to pass several ‘‘hard, black chunks’’ apparently mild amitriptyline overdose. The patient received of particulate matter per rectum, and the obstruction was two 50 g of AC over 4 h, and developed peritonitis 2 days resolved. MDAC was resumed without further incident. The later. Her surgeons discovered an obstructing AC bezoar authors did not actually demonstrate an AC bezoar at the site and a 4-cm diameter perforation together at the sigmoid where it formed. colon. The patient’s methadone use and hospital prescribed Ray et al.3 demonstrated an AC bezoar during lapar- benztropine may have contributed to the obstruction. The otomy. Their patient was a young man being treated for a authors noted that cathartics were not used. In another case massive amitriptyline overdose. The patient was critically report, by Mizutani et al.,7 a patient receiving MDAC for an ill, requiring blood pressure support with epinephrine and organophosphate insecticide ingestion developed a serious military antishock trousers. He received phenytoin, diaze- hemorrhagic rectal ulcer after passing several ‘‘coarse- pam, and morphine for treatment of seizures and agitation. surfaced briquettes’’ measuring 3–5 cm in diameter in her The authors administered 30–60 g of AC every 4–6