time due compensatory response of the body, as well as depletion of -SH groups of glutathione which are essential for the metabolism of the drugs to their active forms. Potential side effects: Verapamil: hypotension, bradycardia, constipation Diltiazem: hypotension, bradycardia, risk of heart block Nifedipine: hypotension Propranolol: asystole, asthma attacks Contraindications Organic nitrates should not be taken with PDE5 inhibitors (i.e. sildenafil) since both NO and PDE5 inhibitors increase cyclic GMP levels and the sum of their pharmacodynamic effects will greatly exceed the optimal therapeutic levels. What you could see upon taking both medications at the same time, as caused by the much higher induction of relaxation of smooth muscle cells, include a severe drop in blood pressure. Beta-receptor antagonists should be avoided in patients with reactive pulmonary disease to avoid asthma attacks. Also Beta-receptor antagonists should be avoided in patients with AV node dysfunction and/or patients on other medications which might cause bradycardia (i.e. calcium channel blockers). The potential for these contraindications and drug-drug interaction could lead to asystole and cardiac arrest. Certain calcium channel blocker should be avoided with some beta-receptor blockers since they may cause severe bradycardia and other potential side effects. Corrective therapy Since vasospasms can be caused by atherosclerosis and contribute to the severity of ischemia there are some surgical options which can restore circulation to these ischemic areas. Regarding coronary vasospasm, one surgical intervention, referred to as percutaneous coronary intervention or angioplasty, involves placing a stent at the site of stenosis in an artery and inflating the stent using a balloon catheter. Another surgical intervention is coronary artery bypass. See also Coronary artery vasospasm Raynaud's phenomenon, a vasospastic disorder Reversible cerebral vasoconstriction syndrome References External links Angiology Neurosurgery