Erectile dysfunction drugs boost chemo

LOS ANGELES, July 29 (UPI) -- Medications prescribed for erectile dysfunction increased delivery of cancer-fighting drugs to treat malignant brain tumors, U.S. researchers said.

Researchers at the Cedars-Sinai Medical Center's Maxine Dunitz Neurosurgical Institute said Viagra, or sildenafil and Levitra, or vardenafil, are known as PDE5 inhibitors because they block an enzyme, phosphodiesterase5, that interrupts a series of biochemical events that cause the decreased blood flow of erectile dysfunction.

A laboratory rat study, published online ahead of print in the journal Brain Research, found that similar biochemical interactions in the small vessels of the brain play a major role in the blood-brain tumor barrier, which impedes delivery of anti-tumor drugs into brain tumors. PDE5 inhibitors were found to open the barrier and increase drug transport in this early animal study.

"This is the first study to show that oral administration of PDE5 inhibitors increases the rate of transport of compounds across the blood-brain tumor barrier and improves the effectiveness of the anti-tumor drug adriamycin in the treatment of brain tumors in a rat model," neurosurgeon Dr. Keith L. Black said in a statement.