A Correlation Study between Drug Dose and Shock Severity in Adults with Amlodipine Poisoning

Background:Calcium channel blockers (CCBs) are increasingly implicated in cardiovascular drug poisoning. Among CCBs, amlodipine is associated with the highest rates of acute toxicity and fatalities. However, the dose-outcome relationship in amlodipine poisoning has not been extensively studied. This study aimed to investigate the correlation between the ingested dose of amlodipine and the severity of shock in affected patients by analyzing clinical data from documented cases. Methods:This study included adult patients treated for amlodipine poisoning-induced shock at the emergency department of Peking University Third Hospital between January 2018 and December 2022. Additionally, cases reported in the literature from January 1997 to December 2022 were also included. Patients were categorized into two groups: shock and refractory shock. Results:This study included a total of 80 patients, with 37 experiencing shock and 43 presenting with refractory shock. Significant differences were observed between the two groups in terms of sex distribution (p=0.037) and the ingested amlodipine dose (p=0.001). Through binary logistic regression analysis, the amlodipine dose was identified as an independent predictor of shock severity (p=0.005). A subgroup analysis was performed on patients who were poisoned by ingesting amlodipine alone, further confirming the significant dose difference (p=0.003) between the shock and refractory shock categories. The area under the receiver operating characteristic curve (AUC) for predicting refractory shock in patients with amlodipine poisoning was 0.723 [95% CI: 0.613, 0.833]. The optimal cutoff dose for predicting refractory shock was 347.5 mg, with a sensitivity of 0.651 and a specificity of 0.784. Sensitivity analyses, excluding cases of mixed poisoning, yielded a higher AUC of 0.795 [95% CI: 0.634, 0.956], with a slightly adjusted cutoff dose of 350 mg, a sensitivity of 0.867, and a specificity of 0.737. Dose‒response relationship plots demonstrated that the incidence of refractory shock increased as the ingested amlodipine dose increased. Conclusion:In adult patients with amlodipine poisoning, the severity of shock was correlated with the ingested dose of the drug. When the ingested amlodipine dose exceeds 347.5 mg, it is crucial to be cautious of the development of refractory shock. Trial registration:Retrospectively registered.