Possible Interaction: Quinine and Verapamil

“The presence of 2 μM verapamil had no effect on mefloquine resistance; however, the presence of verapamil modulated the activities of QN and QD in a manner parallel to that observed for CQ.”

“Increased susceptibility to quinine after addition of verapamil was noted.”

“ Verapamil and quinine , both at levels suitable for human trials that produced only partial sensitization of the MDR1-transgenic mice, were fully sensitizing when used in combination.”

“When used in association, verapamil and quinine reversed doxorubicin resistance in a synergistic fashion.”

“It has been shown that the combination of verapamil and quinine , and of verapamil and cyclosporine A, behave synergistically in the circumvention of multidrug resistance.”

“At each dose level of verapamil tested, the combination with quinine proved more effective than either drug individually in reversing resistance to doxorubicin and vinblastine and synergistic chemosensitizing interaction was observed.”

“Cyclosporine A (50 … mg/kg), verapamil (5mg/kg) or mefloquine (… the brain-to-plasma quinine concentration ratio (by factors of 3.8-, 1.8-, 1.9- and 2.5-fold, respectively) and …-hydroxyquinine ratio in plasma (by factors 2.1-, 3.7-, 1.8- and 2.0-fold, respectively).”

“Furthermore, verapamil had the remarkable effect of antagonizing the QN response while potentiating the QD response of K76I parasites.”

“The structurally related antimalarials amodiaquine and quinine also inhibited labeling of the two proteins, while verapamil and doxycycline had no effect.”

“It was found that although most of the drugs used … prolong the survival of the animals, the administration of verapamil and more so … of aspirin or quinine formate led to a 50 to 100% loss of venom and … toxicity, depending on the drug and the origin of the venom.”