Nicorandil

This chemical does not meet GHS hazard criteria for 1.5% (1 of 66) of reports.

Danger

H302 (98.5%): Harmful if swallowed [Warning Acute toxicity, oral]

P264, P264+P265, P270, P280, P301+P317, P305+P354+P338, P317, P330, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 66 reports by companies from 7 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Drug-Induced Liver Injury Severity and Toxicity (DILIst)

Nicorandil

DILI Positive

DOI:10.1016/j.drudis.2019.09.022

C - Cardiovascular system

QC - Cardiovascular system

Nicorandil is a potassium channel opener with nitrovasodilator (NO donor) actions, making it both an arterial and a venous dilator. It causes sustained dilation of both the arterial resistance and conductive vessels that increases coronary blood flow, however the effect of the drug on coronary arteries does not involve the coronary steal phenomenon. Activation of potassium channels lead to hyperpolarization of the smooth muscle cells, followed by arterial dilation and afterload reduction. Nicorandil is shown to increase pooling in the capacitance vessels with a decrease in preload through relaxing the venous vascular system. Overall, improved blood flow and reduced infarct size are achieved through reduction of end-diastolix pressure and decreased extravascular component of vascular resistance. Open studies showed the effectiveness of nicorandil treatment on various types of angina pectoris.

Nicorandil mediates its therapeutic efficacy via two main mechanisms. Nicorandil is an activator and opener of ATP-sensitive (ATP-dependent) potassium channels (KATP channels) that are composed of Kir6.x-type subunits and sulfonylurea receptor (SUR) subunits. Nicorandil binding sites are located in the sulfonylurea receptor 2 (SUR2) in the ATP-sensitive potassium channel, which are regulatory subunits of the channel that exhibit an ATPase activitiy. There are 2 types of SUR2 subunits (2A/2B) that have identical nucleotide binding domains (NBD), where SUR2A is more predominantly expressed in skeletal and cardiac myocytes and SUR2B in smooth muscle cells. Nicorandil more potently activates SUR2B/Kir6.2 than SUR2A/Kir6.2 channels to cause hyperpolarization. ATP-NBD1 interaction influences the channel signalling by nicorandil, and the response of the channel to nicorandil is also facilitated and heightened by the interaction of ATP or ADP with NBD2. Potentiated activity of ATP-sensitive channels have cardioprotective role by limiting the duration of action potentials and preventing intraceullar calcium overload. This attenuates cellular injury by preserving cellular energetics and ultimately cell survival. KATP channel-dependent membrane hyperpolarization can also lead to vasodilation via reduction in Ca2+ influx through the voltage-gated Ca2+ channels and regulation of intracellular Ca2+ mobilization in smooth muscle cells. Nicorandil contain a nitrate moiety in its structure, making it a good dilator of vascular smooth muscle like other nitroglycerin esters. Direct relaxation of venous vascular system arises from NO-donor mediated stimulation of guanylyl cyclase and increased levels of intracellular cyclic GMP (cGMP). Elevated levels of cGMP contributes to the total relaxing effect of nicorandil at higher concentrations of the drug.