Alpha-blockers are used to treat a variety of conditions, including high blood pressure, Raynaud's disease and to improve urine flow in older men with enlarged prostates. Now, a new study suggests there is a higher risk of ischemic stroke for men who take alpha-blockers but who are not already taking other blood pressure medications.

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Older men who take alpha-blockers are at increased risk of ischemic stroke during the first 21 days of treatment, according to the latest study.

The study is published in the Canadian Medical Association Journal and was led by Dr. Chao-Lun Lai, from the National Taiwan University Hospital, Hsin-Chu Branch.

The researchers explain that alpha-blockers were originally developed to control hypertension, but they are now mainly used by older men with prostate hypertrophy.

The drugs work by relaxing certain muscles and helping small blood vessels stay open. Alpha-blockers keep the hormone norepinephrine from tightening muscles in the walls of smaller arteries and veins.

By blocking that effect, alpha-blockers keep the vessels open and relaxed, improving blood flow and lowering blood pressure.

However, these drugs can have adverse effects, say the researchers, who note that men starting alpha-blockers can see a large decrease in blood pressure within the first few days, increasing risk of stroke.

To investigate to what extent this medication increases stroke risk, the team studied a group of 7,502 Taiwanese men over the age of 50 as they entered the initiation phase of alpha-blockers.

No increased risk for men already taking blood pressure meds

Each patient who took part in the study had both a first stroke and a new prescription of alpha-blockers during the study period, which took place over 3 years.

Fast facts about stroke in the US
  • Stroke kills nearly 130,000 Americans each year
  • Every 4 minutes, an average of one American dies from stroke
  • Around 87% of strokes are ischemic strokes - when blood flow to the brain is blocked.

Learn more about stroke

Results show an increased ischemic stroke risk for men during the first 21 days of starting treatment and a reduced risk 22-60 days after starting treatment.

In detail, men who were not taking other blood pressure drugs has a two-fold increased risk of ischemic stroke during the first 21 days, compared with men who started taking alpha-blockers later.

Interestingly, men who were already taking other blood pressure medications did not have an increased risk of stroke, likely because their bodies were already accustomed to the medications and their blood pressure-stabilizing effects.

As a result of their findings, the researchers "recommend caution when prescribing alpha-blockers to patients who are not taking other antihypertensive medications."

Though their study involved a large sample size, the team admits to some study limitations. For example, they did not include 5-alpha-reductase inhibitors - which is an alternative treatment for benign prostatic hyperplasia.

Additionally, they were not able to determine from the data whether prescribed medications were actually taken by the patients.

Finally, because the study was carried out mainly among Chinese men in Taiwan, the team says further research is needed to investigate whether other ethnicities face the same increased stroke risks.

Medical News Today recently reported on a study that suggested speaking at least two languages may protect against cognitive impairment after stroke.