Characterization of the Synergistic Antibacterial Effect of Verapamil on Bacterial Isolates From Cancer Patients

NCT07505446 | Not Yet Recruiting

• 1 other identifier: Verapamil use in MDR bacteria
• Study Type: observational
• Target: 100
• Locations: 0 countries
• Sites: N/A

Brief Summary

Multidrug-resistant (MDR) bacteria represent a significant global health challenge, particularly among immunocompromised populations such as cancer patients undergoing chemotherapy. These patients are highly susceptible to severe infections due to weakened immune defenses, often necessitating the use of broad-spectrum or combination antibiotic therapy. Combination regimens may enhance treatment efficacy through synergistic effects, helping to overcome bacterial resistance mechanisms and improve clinical outcomes. In recent years, there has been growing interest in the use of non-antibiotic drugs as adjunctive agents to enhance antimicrobial activity. These agents, often referred to as antibiotic adjuvants or resistance modifiers, may improve antibiotic effectiveness through mechanisms such as inhibition of bacterial efflux pumps, disruption of biofilm formation, or interference with resistance pathways. Verapamil, a widely used calcium channel blocker, has demonstrated potential antimicrobial and resistance-modifying properties. Experimental evidence suggests that verapamil can inhibit bacterial efflux pumps, thereby increasing intracellular concentrations of antibiotics and enhancing their activity against resistant organisms. This study aims to evaluate the in vitro synergistic antibacterial activity of verapamil in combination with selected antibiotics against MDR, extensively drug-resistant (XDR), and pandrug-resistant (PDR) bacterial isolates obtained from cancer patients. Standard microbiological methods will be used to determine antimicrobial susceptibility and minimum inhibitory concentrations, while combination effects will be assessed using established synergy testing approaches. The findings of this study may contribute to identifying novel, cost-effective strategies to combat antimicrobial resistance through drug repurposing and optimization of existing antibiotic therapies.

Conditions

Antibiotic Resistance; Multi Drug Resistant Organisms

Keywords

Verapamil; Antibiotic Adjuvant; Efflux Pump Inhibitor; Antimicrobial Synergy; Checkerboard Assay; Fractional Inhibitory Concentration Index (FICI); Minimum Inhibitory Concentration (MIC); MDR / XDR / PDR Bacteria; Cancer Patient Isolates

Outcome Measures

Primary Outcomes (1)

• Characterization of the synergistic antibacterial effect of Verapamil on bacterial isolates from patients in South Egypt Cancer Institute

  Determination of the antibiotic sensitivity patterns of the bacterial isolates as measured by MIC values

  Baseline

Interventions

verapamil DRUG

Intervention Name: Verapamil Other Names: Verapamil hydrochloride Clinical specimens from cancer patients collected for routine testing will be included. Bacterial isolates will be cultured on appropriate media and identified using standard microbiological methods and/or automated systems. Antimicrobial susceptibility testing will be performed using the Kirby-Bauer disk diffusion method or automated systems according to CLSI 2025 guidelines. A stock solution of verapamil will be prepared under aseptic conditions. The antibacterial activity of selected antibiotics alone and in combination with verapamil will be evaluated. Minimum inhibitory concentrations (MICs) will be determined using the broth microdilution method. Synergistic interactions will be assessed using the checkerboard method and quantified by fractional inhibitory concentration index (FICI).

Eligibility Criteria

• Age: 18 Years - 90 Years
• Sex: all
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study will be carried out on clinical specimens of cancer patients already withdrawn for routine testing during the study period

You may qualify if:

• Bacterial isolates from clinical samples submitted for the SECI laboratory for culture and sensitivity testing that are:
• MDR: resistant to one or more agent within three or more of antimicrobial classes
• XDR: resistant to one or more agent within all but two antimicrobial classes
• PDR: resistant to all agents within all antimicrobial classes.

You may not qualify if:

• Bacterial isolates from non-cancer patients.
• Contaminant or non-pathogenic isolates.
• Duplicate isolates from the same patient with identical antibiogram.
• Bacterial isolates that are neither MDR, XDR OR PDR.

Sponsors & Collaborators

• Assiut University: lead

Related Publications (6)

• Yin Q, Shen J, Zhang Z, Yu H, Li Y. Reversal of multidrug resistance by stimuli-responsive drug delivery systems for therapy of tumor. Advanced Drug Delivery Reviews. 2013. doi:10.1016/j.addr.2013.04.011

  BACKGROUND

• Jang J, Kim R, Woo M, et al. Efflux attenuates the antibacterial activity of Q203 in Mycobacterium tuberculosis. Antimicrob Agents Chemother. 2017. doi:10.1128/AAC.02637-16

  BACKGROUND

• Vega-Chacón Y, de Albuquerque MC, Pavarina AC, Goldman GH. Verapamil inhibits efflux pumps in Candida albicans, exhibits synergism with fluconazole, and increases survival of Galleria mellonella. Virulence. 2021. doi:10.1080/21505594.2020.1868814

  BACKGROUND

• Duckett SG, Ginks M, Shetty AK, Knowles BR, Totman JJ, Chiribiri A, Ma YL, Razavi R, Schaeffter T, Carr-White G, Rhode K, Rinaldi CA. Realtime fusion of cardiac magnetic resonance imaging and computed tomography venography with X-ray fluoroscopy to aid cardiac resynchronisation therapy implantation in patients with persistent left superior vena cava. Europace. 2011 Feb;13(2):285-6. doi: 10.1093/europace/euq383. Epub 2010 Oct 25. No abstract available.

  PMID: 20974762 BACKGROUND

• Soons JA, Ricci AJ, Steele CR, Puria S. Cytoarchitecture of the mouse organ of corti from base to apex, determined using in situ two-photon imaging. J Assoc Res Otolaryngol. 2015 Feb;16(1):47-66. doi: 10.1007/s10162-014-0497-1. Epub 2014 Oct 28.

  PMID: 25348579 BACKGROUND

• Enoh J, Orega M, Yao A, Cisse L, Couitchere L, Attimere Y, Niangue M, Andoh J. [Choleriform diarrhea in children in Abdijan]. Arch Pediatr. 2003 Nov;10(11):1009-10. doi: 10.1016/j.arcped.2003.09.026. No abstract available. French.

  PMID: 14613700 BACKGROUND

MeSH Terms

Interventions

Verapamil

Intervention Hierarchy (Ancestors)

Phenethylamines; Ethylamines; Amines; Organic Chemicals

Central Study Contacts

Ahmed I Khalaf Mohamed, Demonstrator

CONTACT

+201144427816; drahmednafady0794@gmail.com

Enas A Daef, professor

CONTACT

+201223971411; Deafenas@yahoo.com

Study Design

• Study Type: observational
• Observational Model: OTHER
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Demonstrator of Cancer Biology, South Egypt Cancer Institute, Assiut University

Study Record Dates

• First Submitted: March 26, 2026
• First Posted: April 1, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): May 1, 2027
• Study Completion (Estimated): June 1, 2027
• Last Updated: April 8, 2026

Record last verified: 2026-04