Possible Interaction: Acetylcysteine and Nitroglycerin

“In both groups, NAC potentiated the increase in CBF in response to nitroglycerin.”

“It has been suggested that the addition of N-acetylcysteine to nitroglycerin reverses the development of tolerance, potentiates the hemodynamic response to nitroglycerin and may improve in-hospital prognosis in unstable angina.”

“Kaplan-Meier curves showed a higher probability (p < 0.01) of no failure of medical treatment in the group receiving both nitroglycerin and N-acetylcysteine than in those receiving placebo, N-acetylcysteine or nitroglycerin alone.”

“The combination of nitroglycerin and N-acetylcysteine was associated with a high incidence of side effects (35%), mainly intolerable headache, which was almost twice as frequent as in patients receiving nitroglycerin alone.”

“We conclude that NAC attenuates tolerance development to a continuous NTG infusion in a specific patient subgroup and that this occurs despite the same amount of neurohormonal counter-regulation and intravascular volume expansion compared with patients with tolerance development.”

“BACKGROUND N-acetylcysteine NAC ) has been shown to potentiate the effects of nitroglycerin (NTG) and to have antioxidant activity.”

“Both the development of nitrate tolerance and the administration of N-acetylcysteine significantly change the normal vasodilator profile of nitroglycerin in humans.”

“N-acetylcysteine had no effect on nitroglycerin-… blood flow after 1 h nitroglycerin … N-acetylcysteine : 6.3 +/- 1.3 ml/100 g per min vs. nitroglycerin plus placebo: 3.5 +/- 0.3 … (4.4 +/- 0.6 vs. 3.1 +/- 0.5 ml/100 g per min, p < 0.05).”

“ N-Acetylcysteine (NAC), a sulfhydryl donor, has been reported to potentiate the effect of nitroglycerin and reverse tolerance in humans.”

“These results suggest that chronic oral administration of N-acetylcysteine fails to prevent the development of tolerance to the anti-anginal or haemodynamic effects of glyceryl trinitrate.”

“Furthermore, interaction of NTG and NAC may lead to the formation of S-nitroso-NAC, which strongly inhibits platelet aggregation.”

“Previous studies in man have shown that the sulfhydryl donor N-acetylcysteine NAC ) potentiates the systemic and coronary vasodilator effects of NTG.”

“It is concluded that combined administration of NTG and NAC in patients with unstable angina pectoris may augment the clinical efficacy of NTG, largely by reducing the incidence of acute myocardial infarction.”

“ N-acetylcysteine (NAC) has been shown to potentiate the haemodynamic and antiplatelet effects of nitroglycerine (NTG) in man, and to limit the development of haemodynamic tolerance to NTG.”

“Short- and long-term studies indicated that also in patients with unstable angina pectoris and threat of infarct, the intravenous or oral administration of N-acetylcysteine in association with nitroglycerin is highly effective in decreasing the risk of worsening, mainly by preventing the occurrence of acute myocardial infarction.”