Viagra Works for the Long Haul March 14
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Oct. 21, 2003 (Salt Lake City) — With prostate cancer treatment success often comes at a heavy price: erectile over the counter erectile dysfunction drug
Michael Zelefsky, MD, of Memorial Sloan-Kettering Cancer Center, N.Y., tells WebMD that the radiation-associated erectile dysfunction usually “begins about six months after they have concluded therapy, but it can occur at any time during or after treatment.” He says that he has already reported that “about 70% of men initially respond to Viagra. However, they didn’t know if the response would be durable.”
In the new study, which was presented at the 45th Annual Meeting of the American Society for Therapeutic Radiology and Oncology, Zelefsky and his colleagues studied the “ed pills
The results, he says, were surprising. “I didn’t really expect them to still be taking the drug and I expected that for many men the effect would diminish with time.” But after almost four years, 96% of the men who initially responded to Viagra were still taking the drug and all but six of those men said the drug was still effective.
All of the men in the study had prostate cancer that was confined to the prostate gland. They received radiation therapy by either external beam treatment or by brachytherapy, in which citrate pfizer sildenafil “seeds” implanted in the prostate deliver radiation directly to the tumor.
The external radiation is done while the patient lies in a special box that allows multiple radiation beams to be directed directly to the prostate gland from all sides, while the rest of the body is protected from the radiation.
Prostate cancer is mainly found in older men. After prostate cancer has been diagnosed, tests are done to determine if it has spread outside the gland. Because there are different treatments available, determining how much the cancer has spread this will help in deciding what treatment is best for the cancer.
Surgery to remove the cancer is one option that is used to treat prostate cancer. Radiation is another therapy used in treating this cancer. Erectile dysfunction can occur in men treated with either one of these treatments.
Zelefsky says the men who reported that Viagra stopped working were those who were treated with extremely high-dose external radiation.
Richard Valicenti, MD, associate professor radiation oncology, at Thomas Jefferson University Hospital, in Philadelphia, tells WebMD that the study is “important since it shows that treatment with Viagra can deliver a durable response.” But Valicenti, who wasn’t involved in the study, says that he, too, is a little surprised by the results, especially because of the fairly large range in the length of treatment and because drug tolerance is common.
“We don’t really know how often they are taking the drug. We know that with repeated use tolerance develops for many drugs and we expect it for this drug as well,” he says.
If tolerance does develop, the new erectile dysfunction drug, Levitra, could be an option says Zelefsky. He says his group is erectile dysfunction
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