01 October 2010
Doctors often use drugs in combination. Sometimes one medicine will enhance the effectiveness of another. Or a drug will have side effects that are eased by a different medicine. Now, researchers have found one drug that does both, and the name of the medicine may surprise you.
This story starts with a powerful anti-cancer drug called doxorubicin. It's effective, but it has a lot of serious side effects, including damage to the heart.
Researchers were looking for a way to ease those cardiac symptoms. Using laboratory mice, they tried out a drug originally developed to treat angina - chest pain - but which turned out to be a hugely successful drug for quite a different problem.
"We are using Viagra, which has been utilized by a vast number of patients for the last 12 years for treatment of erectile dysfunction with virtually no evidence of life-threatening side effects," said Rakesh Kukreja of Virginia Commonwealth University, an author of a paper describing the research.
Viagra [sildenafil], it turns out, did a good job of easing the heart-related side-effects of the cancer treatment. But the researchers were worried it might also reduce the tumor-fighting properties of doxorubicin. However, in their study, Kukreja says it actually increased the effectiveness of the cancer drug.
"That was a huge surprise. We thought that, in order for this drug to be used for protecting the heart, we needed to rule out that it did not interfere with the efficacy of doxorubicin for treatment of cancer. So we found the opposite results, where we saw, actually, enhanced anti-tumor effect of doxorubicin in prostate cancer."
And in a couple of other cancers, too.
Kukreja says the next step will be human trials, to see how the doxorubicin-Viagra combination works in actual patients.
A paper describing the research is published online by the Proceedings of the National Academy of Sciences.