Verapamil ((±)-Verapamil) is a calcium channel blocker and a potent and orally active first-generation P-glycoprotein (P-gp) inhibitor. Verapamil also inhibits CYP3A4. Verapamil has the potential for high blood pressure, heart arrhythmias and angina research[1][2][3].

The EverFluor FL Verapamil (EFV) uptake by TR-iBRB2 cells is inhibited by cationic drugs, and inhibits by verapamil in a concentration-dependent manner with an IC50 of 98.0 μM[4].

Given orally Verapamil is useful for the prophylaxis of atrioventricular reentry tachycardia, and also in modulating the atrioventricular nodal response in atrial fibrillation[2].Verapamil is injected i.v. into a femoral vein prior to ischemia. Verapamil (1 mg/kg) significantly decreases the incidence of ventricular arrhythmias including premature ventricular contractions (PVC), ventricular tachycardia (VT) and ventricular fibrillation (VF) for 45-min coronary artery occlusion. Total arrhythmia scores are significantly increased when the heart is subjected to ischemia. Verapamil (1 mg/kg) significantly prevents the enhancement of total arrhythmia scores induced by ischemia[5].

[1]. Gowarty JL, et al. Verapamil as a culprit of palbociclib toxicity. J Oncol Pharm Pract. 2019 Apr;25(3):743-746. [2]. Krikler DM. Verapamil in arrhythmia. Br J Clin Pharmacol. 1986;21 Suppl 2:183S-189S. [3]. Rehnqvist N,et al. Effects of metoprolol vs verapamil in patients with stable angina pectoris. The Angina Prognosis Study in Stockholm (APSIS). Eur Heart J. 1996 Jan;17(1):76-81. [4]. Kubo Y, et al. Blood-to-Retina Transport of Fluorescence-Labeled Verapamil at the Blood-Retinal Barrier. Pharm Res. 2018 Mar 12;35(5):93. [5]. Zhou P, et al. Anti-arrhythmic effect of Verapamil is accompanied by preservation of cx43 protein in rat heart. PLoS One. 2013 Aug 12;8(8):e71567.