Granisetron Hcl(BRL 43694A) is a serotonin 5-HT3 receptor antagonist used as an antiemetic to treat nausea and vomiting following chemotherapy.IC50 Value: 17uM (GR reduced 5-HT-evoked contractions) [1]Target: 5-HT3 receptorin vitro: In rat forestomach GR reduced 5-HT-evoked contractions at IC50 17 /- 6 uM. In isolated rabbit heart, GR 0.003-0.03 nM dose-dependently reduced s-HT tachycardia; at high levels GR reduced submaximal and maximal responses to 5-HT [1].in vivo: Leukocyte accumulation was dose-dependently inhibited by granisetron both at 6 and 72 h after induction of inflammation. Granisetron increased PGE(2) level at a lower dose (50 microg/pouch) but higher doses (100 and 200 microg/pouch) inhibited the release. At the same time, TNFalpha production was decreased by the lower dose and increased by higher doses of granisetron in a reciprocal fashion [2]. The GTDS displayed non-inferiority to oral granisetron: complete control was achieved by 60% of patients in the GTDS group, and 65% in the oral granisetron group (treatment difference, -5%; 95% confidence interval, -13-3). Both treatments were well tolerated, the most common adverse event being constipation [3].Clinical trial: Effect of External Heat on a Transdermal Granisetron Patch in Pharmacokinetics (PK) of Healthy Subjects. Phase 1

References:
[1]. Sanger GJ, Nelson DR. Selective and functional 5-hydroxytryptamine3 receptor antagonism by BRL 43694 (granisetron). Eur J Pharmacol. 1989 Jan 10;159(2):113-24.
[2]. Maleki-Dizaji N, Eteraf-Oskouei T, Fakhrjou A, The effects of 5HT3 receptor antagonist granisetron on inflammatory parameters and angiogenesis in the air-pouch model of inflammation. Int Immunopharmacol. 2010 Sep;10(9):1010-6.
[3]. Boccia RV, Gordan LN, Clark G, Efficacy and tolerability of transdermal granisetron for the control of chemotherapy-induced nausea and vomiting associated with moderately and highly emetogenic multi-day chemotherapy: a randomized, double-blind, phase III