The Poison Review

Venlafaxine Pharmacobezoar Causing Intestinal Ischemia Requiring Emergency Hemicolectomy. Lung D et a. J Med Toxicol 2011 Mar 4. [Epub ahead of print]

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Yesterday we discussed the humongous review of pharmacobezoars that appears in the current issue of Clinical Toxicology.  This morning, while trolling through PubMed, I came across this spectacular case report recently posted online before publication.

The report describes a 28-year-old woman who ingested up to 10 g of venlafaxine ER tablets.  At 5 hours after ingestion she had mild tachycardia but was asymptomatic except for tremulousness.  She was treated with lorazepam and a single 100 g dose of activated charcoal; no other GI decontamination was carried out because of concern for possible seizures.  Twenty-eight hours after ingestion, she developed right lower quadrant pain and an elevated white blood cell count.  CT scan (reproduced above) showed “extensive scalloping of the wall of the entire right colon with air in the wall”. On laparotomy the cecum and ascending colon were necrotic. There were more than 80 venlafaxine ER tabelets in the cecum.  A right hemicolectomy was performed.

Venlafaxine (Effexor) inhibits reuptake of serotonin and norepinephrine.  The authors hypothesize that the cecal necrosis was caused by developing intestinal obstruction, perhaps exacerbated by focal vasoconstriction caused by the local effects of the drug.

This is a fascinating well written article.  Its concise discussion of pharmacobezoars is more informative (and certainly more digestible) than the Clinical Toxicology behemoth.  The illustrations are amazing. Recommended reading.

[The CT scan reproduced above is from the article, which is available through Open Access under  terms of the Creative Commons Attribution Noncommercial License.]