Niflumic acid, a Ca2+-activated Cl- channel blocker, is an analgesic and anti-inflammatory agent used in the treatment of rheumatoid arthritis.Target: Othersniflumic acid, an inhibitor of calcium-activated chloride currents. Niflumic acid does not block directly calcium channels or activate potassium channels. Niflumic acid selectively reduces a component of noradrenaline- and 5-HT-induced pressor responses by inhibiting a mechanism which leads to the opening of voltage-gated calcium channels [1]. Niflumic acid molecule is completely buried in the substrate-binding hydrophobic channel. The conformations of the binding site in PLA(2) as well as that of niflumic acid are not altered upon binding [2]. Niflumic acid (NFA) produces biphasic behavior on human CLC-K channels that suggests the presence of two functionally different binding sites: an activating site and a blocking site [3].

References:
[1]. Criddle, D.N., et al., Inhibitory action of niflumic acid on noradrenaline- and 5-hydroxytryptamine-induced pressor responses in the isolated mesenteric vascular bed of the rat. Br J Pharmacol, 1997. 120(5): p. 813-8.
[2]. Jabeen, T., et al., Non-steroidal anti-inflammatory drugs as potent inhibitors of phospholipase A2: structure of the complex of phospholipase A2 with niflumic acid at 2.5 Angstroms resolution. Acta Crystallogr D Biol Crystallogr, 2005. 61(Pt 12): p. 1579-
[3]. Picollo, A., et al., Mechanism of interaction of niflumic acid with heterologously expressed kidney CLC-K chloride channels. J Membr Biol, 2007. 216(2-3): p. 73-82.