May 19 (HealthDay News) -- Men taking Flomax to treat an enlarged prostate face more than double the risk for serious complications should they need cataract surgery, a new Canadian study has found.

It's not the first time that Flomax (tamsulosin) has been linked to cataract complications. A study in 2005 found that men taking Flomax or other alpha-blockers before cataract surgery had complications during and immediately after the procedure. The U.S. Food and Drug Administration called for stronger warnings about the drug, and Boehringer Ingelheim Pharmaceuticals, which makes Flomax, sent warning letters to doctors about the potential problems.

In the new study, 7.5 percent of the men who had taken Flomax in the two weeks before cataract surgery had a serious complication, compared with 2.7 percent of those who had not taken the drug, for a 2.3 times greater risk.

The problems were not found to the same extent among men taking other alpha-blockers, said the lead researcher, Dr. Chaim M. Bell, a scientist at the Keenan Research Centre at St. Michael's Hospital in Toronto and assistant professor at the University of Toronto.

"Patients that were prescribed tamsulosin had an over twofold increase in their risk of adverse events after cataract surgery," Bell said. The findings are in the May 20 issue of the Journal of the American Medical Association.

Whether stopping the drug before cataract surgery would reduce the risk of complications is not clear, he said. But before taking Flomax, people should be made aware of the risks, including the risk associated with cataract surgery, he said.

In addition, he said, surgeons need to know if a patient is taking Flomax so that the procedure can be adjusted to take the risks into account. "A better system needs to be in place to better identify patients taking Flomax so that surgeons can best prepare during the operation," he said.

A spokeswoman for Boehringer Ingelheim said the drug maker continues to stand behind its product and believes Flomax is safe when used in the prescribed manner.

"Boehringer Ingelheim is analyzing the data to determine whether it will impact our understanding of the risks and benefits of Flomax capsules in any way," said company spokeswoman Susan Holz.

Information given doctors and patients states "that if patients are considering cataract surgery, they should tell their eye surgeon if they are taking or have taken Flomax," Holz said. "This information is also included in all patient communications regarding Flomax. The Flomax Prescribing Information also states that the patient's eye surgeon should be prepared for possible modifications to the surgical technique for any patient who has taken Flomax."

For the study, Bell's team collected data on 96,128 Canadian men, 66 years and older, who had cataract surgery between 2002 and 2007. Among them, 3,550 had taken Flomax in the two weeks before cataract surgery, and 1,006 had taken the drug more than two weeks before their surgery. In addition, 9,109 men had been taking similar drugs.

In the two weeks after surgery, 284 of the men had a serious complication. Of these, 175 underwent another operation because of a lost lens or lens fragment, 35 had retinal detachment and 26 had both complications. An additional 100 had suspected inflammation within or around the eye.

Flomax is often prescribed to treat an enlarged prostate, a condition known as benign prostatic hyperplasia, or BPH, which affects almost three of four men 70 and older. Symptoms include difficulty urinating. Flomax accounted for $1 billion in sales in 2007, according to the researchers.

Dr. David F. Chang, a clinical professor of ophthalmology at the University of California, San Francisco, said that the study strengthens the existing evidence about risks associated with taking Flomax before cataract surgery.

Most doctors who perform cataract surgery, Chang said, would not start taking the drug themselves if they knew they were likely to need cataract surgery. "If we ophthalmologist were patients, we would want to hear about some of the options," he said. "If I needed cataract surgery, I might want to put off taking any alpha-blocker or possibly take another drug."

Chang was a researcher on the original study that linked Flomax with cataract surgery complications, and "this study supports the observations we laid out," he said.

But, he said, because the risks of complications are relatively small, men who are already taking Flomax should not stop taking the drug and should not be afraid to undergo cataract surgery. "The risks are acceptable," he said. "On the other hand, it would be a shame to have a patient start on an elective medicine like Flomax within a few months of when they need cataract surgery."

SOURCES: Chaim M. Bell, M.D., Ph.D., scientist, Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, and assistant professor, University of Toronto; David F. Chang, M.D., clinical professor, ophthalmology, School of Medicine, University of California, San Francisco; Susan Holz, spokeswoman, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Conn.; May 20, 2009, Journal of the American Medical Association