Erectile Dysfunction drugs help treat brain tumors: study

In a study using laboratory animals, researchers found that medications commonly prescribed for erectile dysfunction opened a mechanism called the blood-brain tumor barrier and increased delivery of cancer-fighting drugs to malignant brain tumors.

Tests in rats showed two erectile dysfunction drugs — Schering-Plough’s Levitra and Pfizer’s Viagra — helped carry a chemotherapy drug past the blood-brain barrier, the team at Cedars-Sinai Medical Centre in Los Angeles said.

Viagra (sildenafil) and Levitra (vardenafil) are known as PDE5 inhibitors because they block an enzyme, phosphodiesterase5, which interrupts a series of biochemical events that cause the decreased blood flow of erectile dysfunction. This laboratory rat study, published online ahead of print in the journal, 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.

“We chose adriamycin for this study because it is one of the most effective drugs against brain tumour cell lines in the laboratory but it has very little effect in animals and humans because it is unable to cross the blood-brain tumour barrier,” neurosurgeon Dr. Keith Black, who led the study, said in a statement.

“The combination of vardenafil and adriamycin resulted in longer survival and smaller tumour size,” Black said.

Although the researchers exposed the laboratory animals to doses of sildenafil and vardenafil that are comparable to the dose range approved for erectile dysfunction in humans, there were no detectable side effects in the rats, and neither drug increased transport of tracers into normal brain tissue.

The experiments were conducted at Cedars-Sinai Medical Center’s Maxine Dunitz Neurosurgical Institute and published in Brain Research.

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