Dose-related haemodynamic effects and pharmacokinetics of oral nicorandil in patients evaluated for chest pain

Nicorandil-induced hyperkalemia in a uremic patient

Nicorandil is an antianginal agent with nitrate-like and ATP-sensitive potassium channel activator properties. After activation of potassium channels, potassium ions are expelled out of the cells, which lead to membrane hyperpolarization, closure of voltage-gated calcium channels, and finally vasodilation. We present a uremic case suffering from repeated junctional bradycardia, especially before hemodialysis. After detailed evaluation, nicorandil was suspected to be the cause of hyperkalemia which induced bradycardia. This case reminds us that physicians should be aware of this potential complication in patients receiving ATP-sensitive potassium channel activator.

Intravenous nicorandil prevents thiamylal-fentanyl-induced bronchoconstriction in humans

OBJECTIVE

Nicorandil has a hybrid property between nitrates and potassium channel openers and has been reported to cause a concentration-dependent relaxation of isolated guinea pig trachealis. Experimental asthma in a guinea pig model was also inhibited by nicorandil. However, no clinical data on the bronchorelaxant effects of this drug have been published. The aim of this study was to investigate whether intravenous nicorandil prevents thiamylal-fentanyl-induced bronchoconstriction.

DESIGN

Double-blind, prospective, placebo-controlled, randomized study.

PATIENTS

A total of 36 patients were randomly allocated to two groups: a control group (n = 18) and a nicorandil group (n = 18).

INTERVENTIONS

Intravenous administration of nicorandil or a placebo (normal saline).

MEASUREMENTS AND MAIN RESULTS

Anesthesia was induced with 5 mg/kg thiamylal and 0.3 mg/kg vecuronium. A continuous infusion of 15 mg x kg(-1) x hr(-1) thiamylal was then used to maintain the anesthesia. Controlled ventilation was maintained, delivering 50% nitrous oxide in oxygen. At 20 mins after the induction of anesthesia, the control group patients were given a 6 mL/hr continuous infusion of normal saline and the nicorandil group patients were given a 6 mg x hr(-1) (6 mL/hr) continuous infusion of nicorandil for 60 mins. At 30 mins after the start of the study, both groups received a 5-microg/kg dose of fentanyl. Systolic and diastolic arterial pressure, heart rate, mean airway resistance, expiratory airway resistance, and dynamic lung compliance were measured for the baseline condition, just before the administration of fentanyl (T30), at three consecutive 6-min intervals after the fentanyl injection (T36, T42, and T48) and 30 mins after the fentanyl injection (T60). Both groups had comparable baseline values for mean airway resistance, expiratory airway resistance, and dynamic lung compliance. In the control group, both mean airway resistance and expiratory airway resistance increased significantly at T36-60, compared with the baseline values, and dynamic lung compliance decreased significantly at T36-60, compared with the baseline value. In the nicorandil group, no changes in mean airway resistance, expiratory airway resistance, or dynamic lung compliance occurred at T36-60.

CONCLUSIONS

Our observations suggest that the intravenous administration of nicorandil has a bronchodilator effect in humans.

Safety of oral nicorandil before coronary artery bypass graft surgery

Nicorandil is a K(ATP) channel opener used to treat angina. It is cardioprotective and a vasodilator. We conducted a prospective, randomized, double-blind, placebo-controlled study to assess oral nicorandil in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). Twenty-two patients received nicorandil (10 mg twice a day) and 23 patients received placebo. Haemodynamic data were recorded before induction of anaesthesia (T0), 5 and 20 min after starting mechanical ventilation (T1, T2), before aortic cannulation (T3), after 30 min of CPB (T4), 10 min after CPB (T5) and after 3, 8 and 18 h in the intensive care unit (T6, T7, T8). Serum proteins (creatine kinase metabolite and cardiac troponin I) were measured before and 8 and 18 h after surgery. Haemodynamic values did not differ between the two groups. There was no tachycardia during the study, no significant difference in hypotensive episodes, ST segment changes and no changes in cardiac enzymes. Myocardial infarction after surgery was similar in the two groups. Vasoactive therapy was similar in the two groups. Nicorandil can be continued safely up to premedication without deleterious haemodynamic consequences, but a myocardial protective effect of nicorandil in CABG surgery was not found.

[Nicorandil: acute hemodynamic effects of 2 different oral doses of a potassium channel opener in patients with coronary heart disease]

BACKGROUND

In medical treatment of angina pectoris the 3 major groups of antianginal agents are nitrates, beta blockers and calcium antagonists. Now a new class of drugs is introduced in the therapy: the potassium channel openers. One of the first potassium channel openers is nicorandil. We examined the acute hemodynamic effects of 2 different oral nicorandil doses in patients with coronary heart disease.

PATIENTS AND METHODS

Twenty patients with angiographic proven coronary heart disease and stable angina pectoris were treated with a dose of 2 x 10 mg Nicorandil on day 1 and 2 x 20 mg Nicorandil on day 2, while being hemodynamically monitored on an intensive care unit with a pulmonary artery catheter.

RESULTS

Through the hemodynamic monitoring a dose dependent, significant reduction of systolic blood pressure was found (6%/9%), while the heart rate increased dose dependently (6%/11%). The rate pressure product as a marker of myocardial oxygen demand did not increase significantly.

CONCLUSION

The oral application of nicorandil causes an acute, dose dependent, significant decrease in systolic blood pressure and induces a reflextachycardia.