Editing Vasospasm (section)

==Treatment==
The occurrence of vasospasm can be reduced by preventing the occurrence of [[atherosclerosis]]. This can be done in several ways, the most important being lifestyle modifications—decreasing [[low-density lipoprotein]] (LDL), [[quitting smoking]], [[physical activity]], and control for other risk factors including [[diabetes]], [[obesity]], and [[hypertension]]. [[Pharmacological therapy|Pharmacological therapies]] include [[hypolipidemic agent]]s, [[thrombolytics]] and [[anticoagulants]]. Pharmacological options for reducing the severity and occurrence of [[ischemia|ischemic episodes]] include the [[organic nitrates]], which are rapidly metabolized to release [[nitric oxide]] in many tissues,<ref>{{cite web |url=https://www.ncbi.nlm.nih.gov/books/NBK547928/ |date=2018-04-27 |title=Organic Nitrates |access-date=2023-03-27 |language=en |pmid=31643263 }}</ref> and are classified as having either long-acting (i.e. [[isosorbide dinitrate]]) or short-acting (i.e. [[nitroglycerin]]) durations of action.

These drugs work by increasing [[nitric oxide]] levels in the blood and inducing coronary [[vasodilation]] which will allow for more coronary blood flow due to a decreased coronary resistance, allowing for increased oxygen supply to the vital organs (myocardium). The nitric oxide increase in the blood resulting from these drugs also causes dilation of systemic veins which in turn causes a reduction in venous return, ventricular work load and ventricular radius. All of these reductions contribute to the decrease in ventricular wall stress which is significant because this causes the demand of oxygen to decrease. In general organic nitrates decrease oxygen demand and increase oxygen supply. It is this favourable change to the body that can decrease the severity of ischemic symptoms, particularly angina.

Other medications used to reduce the occurrence and severity of vasospasm and ultimately ischemia include [[L-type calcium channel#L-type calcium channel|L-type]] [[calcium channel blockers]] (notably [[nimodipine]], as well as [[verapamil]], [[diltiazem]], [[nifedipine]]) and beta-receptor antagonists (more commonly known as [[beta blockers]] or β-blockers) such as [[propranolol]].

L-type calcium channel blockers can induce dilation of the coronary arteries while also decreasing the heart's demand for oxygen by reducing [[Myocardial contractility|contractility]], heart rate, and wall stress. The reduction of these latter three factors decreases the contractile force that the myocardium must exert in order to achieve the same level of [[cardiac output]].

Beta-receptor antagonists do not cause vasodilation, but like L-type calcium channel blockers, they do reduce the heart's demand for oxygen. This reduction similarly results from a decrease in heart rate, afterload, and wall stress.

===Adverse effects===
Like most pharmacological therapeutic options, there are risks that should be considered. For these drugs in particular, vasodilation can be associated with some adverse effects which might include orthostatic hypotension, reflex [[tachycardia]], headaches and palpitations. Tolerance may also develop over 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]].