To investigate the effects of verapamil on left ventricular systolic and diastolic function in patients with hypertrophic cardiomyopathy, we studied 14 patients at catheterization with a nonimaging scintillation probe before and after serial intravenous infusions of low-, medium-, and high-dose verapamil (total dose 0.17 to 0.72 mg/kg). Percent change in radionuclide stroke counts after verapam...

OBJECTIVE To evaluate prospectively the effects of pretreatment with verapamil on the maintenance of sinus rhythm after direct current (DC) cardioversion. DESIGN Randomised, active control, open label, parallel group comparison of verapamil versus digoxin. SETTINGS Multicentre study in three teaching and three non-teaching hospitals in Sweden. PATIENTS 100 consecutive patients with atrial...

BACKGROUND Non-dihydropyridine calcium antagonists such as verapamil are equally effective in reducing proteinuria as ACE inhibitors in hypertensive patients with diabetic nephropathy. To date it is unknown whether verapamil elucidates such an antiproteinuric capacity in non-diabetic renal disease. METHODS We performed a double-blind, placebo-controlled, random cross-over study which compared...

The effects of verapamil on the cytotoxicity and accumulation of multiple drugs were studied in a model of pleiotropic resistance generated by doxorubicin (DOX) selection of the human sarcoma cell line MES-SA. The in vitro sensitivity of the DOX-resistant variant (named Dx5), which is 50- to 100-fold resistant to DOX compared to MES-SA, was enhanced approximately 7-fold by verapamil (3 microgra...

BACKGROUND Verapamil is traditionally applied prophylactically in transradial procedures to prevent radial artery spasm. However, verapamil may have side effects and is contraindicated in some clinical settings. METHODS AND RESULTS During an investigator-initiated, randomized, double-blind trial, we evaluated the need for preventive verapamil administration. After vascular access was establis...

We investigated the effect of the phenylalkylamine Ca(2+) channel inhibitor verapamil on voltage-dependent K(+) (Kv) channels in rabbit coronary arterial smooth muscle cells using a whole-cell patch clamp technique. Verapamil reduced the Kv current amplitude in a concentration-dependent manner. The apparent K(d) value for Kv channel inhibition was 0.82 microM. Although verapamil had no effect o...

P-glycoprotein (P-gp; ABCB1) actively transports a broad range of structurally unrelated compounds out of the cell. An important step in the transport cycle is coupling of drug binding with ATP hydrolysis. Drug substrates such as verapamil bind in a common drug-binding pocket at the interface between the TM (transmembrane) domains of P-gp and stimulate ATPase activity. In the present study, we ...

objective(s): chemoresistance remains the main causes of treatment failure and mortality in cancer patients. there is an urgent need to investigate novel approaches to improve current therapeutic modalities and increase cancer patients' survival. induction of drug efflux due to overexpression of                  p-glycoproteins is considered as an important leading cause of multidrug resis...

Calcium channel antagonists have diverse effects on cardiac electrophysiology. We studied the effects of verapamil, diltiazem, and nifedipine on HERG K+ channels that encode IKr in native heart cells. In our experiments, verapamil caused high-affinity block of HERG current (IC50=143.0 nmol/L), a value close to those reported for verapamil block of L-type Ca2+ channels, whereas diltiazem weakly ...

The binding of verapamil to the protein human serum albumin (HSA) was examined by using high-performance affinity chromatography. Many previous reports have investigated the binding of verapamil with HSA, but the exact strength and nature of this interaction (e.g. the number and location of binding sites) is still unclear. In this study, frontal analysis indicated that at least one major bindin...