Fantofarone (Synonyms: SR 33557)

Fantofarone is a highly potent Calcium Channel antagonist.

It can be seen that the calcium channel blockers VIZ and Fantofarone (SR) possess a weak intrinsic antimalarial property compared to CQ, and both appear slightly more potent on the CQ-resistant than on the CQ-sensitive parasites. Interestingly, Fantofarone is ca. 10 times more potent than verapamil. Fantofarone (SR) is 10 times more potent than the phenylalkylamine verapamil (VR) on the two P. fdciparum strains. As revealed by the isobolograms, the two calcium channel blockers potentiate the CQ sensitivity activity on the CQ-resistant P. fufcipurum strain, verapamil appearing 2 to 3 times more potent than Fantofarone. Furthermore, when used at similar subinhibitory fractions of their IC50, VR is 2 to 3 times more potent than Fantofarone in decreasing CQ resistance[1].

Treatment with isosorbide dinitrate (0.3 mg/kg, i.v.) or Fantofarone (50 mg/kg, i.v.), a reduction is observed in the occurrence and severity of vasospasm, whereas verapamil (0.2 mg/kg, i.v.) is much less effective. Although it totally inhibits distal AIV, isosorbide dinitrate does not significantly affect proximal diameter decrease. The most potent compound with regard to both the distal and proximal vasospasms is Fantofarone, which significantly reduces AIV throughout the experiment. Verapamil does not reduce AIV significantly[2].

References:
[1]. Adovelande J, et al. Synergy between two calcium channel blockers, verapamil and fantofarone (SR33557), in reversing chloroquine resistance in Plasmodium falciparum. Biochem Pharmacol. 1998 Feb 15;55(4):433-40.
[2]. Dongay B, et al. Effect of fantofarone, a new Ca2+ channel antagonist, on angioplasty-induced vasospasm in an atherosclerotic rabbit model. Biochem Pharmacol. 1998 Jun 15;55(12):2047-50.