Characterizing pharmacobezoar formation: a descriptive analysis from VigiBase

Abstract

Introduction: Pharmacobezoars are concretions of drugs that can persist within the gastrointestinal tract and can lead to mechanical obstruction and pharmacological toxicity. We aimed to provide a descriptive analysis of reported cases of pharmacobezoar in VigiBase, the World Health Organization global database of adverse event reports for medicines and vaccines.

Methods: We conducted a descriptive analysis of all de-duplicated individual case safety reports related to pharmacobezoars recorded in VigiBase, from its inception in 1968 to March 2, 2025. In a subgroup analysis, we selected reports containing at least one Preferred Term related to drug overdose, misuse, or suicidal behavior to identify potential cases of acute intoxication.

Results: A total of 632 individual case safety reports related to pharmacobezoars were analyzed. These primarily involved male patients (n = 318; 50.3%), with a median age of 60.0 years (IQR 43.0-71.0 years). Overall, 432 reports (68.4%) described serious adverse drug reactions. The most frequently involved drugs were carbidopa/levodopa (n = 148; 23.4%), quetiapine (n = 63; 10.0%), sucralfate (n = 46; 7.3%), nifedipine (n = 41; 6.5%), and acetylsalicylic acid (n = 40; 6.3%). The subgroup analysis included 158 reports related to acute intoxications, mostly involving female patients (n = 103; 65.2%), with a median age of 43.0 years (IQR 24.0-54.0 years). Almost all were serious (n = 156; 98.7%), with quetiapine, venlafaxine, ibuprofen, acetylsalicylic acid, paracetamol, and lorazepam most frequently reported.

Discussion: The findings highlight the clinical severity and heterogeneous presentation of pharmacobezoars. Carbidopa/levodopa was frequently reported, possibly reflecting underlying conditions such as Parkinson disease with delayed gastric motility. The high prevalence of psychotropics underscores the need for targeted prevention in at-risk populations, particularly those with psychiatric comorbidities.

Conclusions: While pharmacobezoars are rare, their association with serious and potentially fatal outcomes warrants increased clinical awareness. Early recognition and appropriate management may be particularly important in cases involving high-risk drugs.

Keywords: Bezoars; VigiBase; drug overdose; pharmacovigilance; poisoning.