Effects Of Methadone On The Vascular System

Methadone is used as a long-term treatment of dependence on opioid drugs. Methadone maintenance is often used to help patients stay off heroin, but it may also be used to help patients stop abusing prescription narcotics such as oxycontin. Like virtually all medications, methadone has a long list of side effects, as noted by Drs. Michael Weaver and John Hopper in the medical reference UpToDate, some of which impact the vascular system.

Orthostatic Hypotension

Methadone use may result in orthostatic hypotension. This means that when the patient who is taking methadone stands up after having been sitting down, his blood vessels dilate, and his blood pressure goes down. This may cause lightheadedness, dizziness, or in more severe cases, fainting.

Phlebitis

Phlebitis, also known as thrombophlebitis, is the inflammation of a blood vein. This inflammation may cause pain and tenderness around the inflamed blood vessel. Patients with phlebitis may notice that the area is warm or red, and there may be swelling around the inflamed blood vessel as well. The medical reference UpToDate does not quantify what percentage of patients may be expected to experience this side effect of methadone, but does indicate that it is a significant potential adverse effect.

Syncope

Another potential effect that methadone may have on the circulatory system is that of syncope. Syncope is a medical term used to indicate a brief loss of consciousness and muscle control--also known as "passing out" or fainting. This may be due to a closely-related side effect of methadone: low blood pressure, or hypotension. Hypotension may result in fainting because there is not enough blood going to the brain; without this needed blood, the person loses consciousness.

Abnormal Heart Rates and Rhythms

Methadone may also influence the cardiovascular system in a variety of dangerous ways. Abnormal heart rhythms, called arrhythmias, are a risk for patients taking methadone. Bradycardia, which is a heart rate of fewer than 60 beats per minute, may also be experienced by patients on methadone. A life-threatening heart rhythm known as ventricular fibrillation may occur. Also, patients are at risk for a rhythm known as torsade de pointes, named for its characteristic appearance on the electrocardiogram, or ECG. Finally, patients are at risk for cardiac arrest due to these abnormal rhythms.