A study conducted by Dr. Chao-Lun Lai and his team, from the National Taiwan University Hospital, Hsin-Chu Branch, suggests that older men taking alpha-blockers may be at an increased risk of ischemic stroke, if they are not already taking other blood pressure medications. Alpha blockers are themselves used to treat high blood pressure – or hypertension – but can also be taken to improve urine flow in men with enlarged prostates.
According to Lai and his team, while alpha-blockers were originally designed to treat hypertension, they are now often prescribed to men with prostate enlargement. The results of the study were published in the Canadian Medical Association Journal.
Alpha-blockers work by inhibiting norepinephrine – a hormone that acts to tighten the muscles in the walls of small blood vessels, thereby helping small arteries and veins to stay open. Blood vessels which are more open allow blood to move freely, which lowers overall blood pressure.
Sometimes the decrease in blood pressure in patients taking alpha-blockers for the first time can be extreme, leading to an increased risk of stroke. In order to further understand the risk of stroke, the researchers followed 7,502 Taiwanese men ages 50 and older, as they started treatment with alpha-blockers.
The study was conducted over a 3 year period in which all of the patients experienced a first stroke which precipitated their being prescribed alpha-blockers. The study investigators found that ischemic stroke risk was increased during the initial 21 days of treatment, which was then reduced during days 22 to 60 of treatment with alpha-blockers.
Men enrolled in the study who were not taking any other medications to control blood pressure had a 2 times higher risk of stroke during the initiation phase of treatment with alpha-blocker drugs. Importantly, men who were already taking other drugs to control blood pressure showed no increased risk of stroke after starting treatment with alpha-blockers.
In response to their findings, the study investigators, “recommend caution when prescribing alpha-blockers to patients who are not taking other antihypertensive medications.” While the team conducted the study using a large sample size, they do point out a few limitations to their trial design.
Firstly, the researchers did not compared treatment with alpha-blockers to alternative treatments for benign prostatic hyperplasia – or enlarged prostate – such as 5-alpha-reductase inhibitor drugs. In addition, the researchers could not guarantee patient adherence to a treatment schedule, as it was unclear from the data collected whether all patients took the medication as prescribed.
It is also unclear whether the results of this study will be applicable to older men of other ethnicities, as the study was conducted using only Taiwanese patients. The researchers point out the need for further clinical trials in order to substantiate their results.
Sources:
- Stroke risk for older men who take alpha-blockers – http://www.medicalnewstoday.com/articles/303667.php
- Lai, C., Kuo, R., Chen, H., Chen., M., Chan., K., and Lai, M. (2015). Risk of ischemic stroke during the initiation period of α-blocker therapy among older men. Can Med Assoc J.
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