Related Experiment Video
Updated: Feb 13, 2026

Measuring RAN Peptide Toxicity in C. elegans
Published on: April 30, 2020
Verapamil as a culprit of palbociclib toxicity
Jasmine L Gowarty1, Jon D Herrington1
1Scott and White Medical Center-Temple, Temple, TX, USA.
Abstract:
A promising drug, palbociclib, received accelerated approval as a first line treatment when used with the aromatase inhibitor, letrozole, for postmenopausal women with hormone receptor positive advanced or metastatic breast cancer. We report a case of a patient who presented with febrile neutropenia, grade 3 stomatitis with lip swelling, periorbital edema, and transaminitis while on palbociclib and verapamil. Labs normalized upon discontinuation of verapamil and our patient was able to continue treatment with palbociclib and letrozole. Verapamil's inhibition of both permeability-glycoprotein (P-gp) and CYP3A4 is suspected to have led to the adverse side effects seen in our patient.
Related Concept Videos
Toxicity Testing in Animals
Toxic Reactions: Overview
Toxicity falls into two primary categories: local and systemic.
Local toxicity appears at the exposure site, such as protein denaturation caused by caustic substances.
In contrast, systemic toxicity requires the toxic agent's absorption and distribution,...
Drug Toxicity: Overview
Bioactivation and Tissue Toxicity
Drug Toxicity: Risk factors
Drug toxicity: Idiosyncratic Reactions

