Impotence drugs make chemotherapy more effective in rats
A US study has found that drugs used to treat impotence appear to help improve the effectiveness of chemotherapy in rats with brain tumours.
Researchers at Cedars-Sinai Medical Centre found that 'phosphodiesterase5 (PDE5) inhibitor' drugs like Viagra (sildenafil) and Levitra (vardenafil), which increase bloodflow to the penis in people with erectile dysfunction (ED), can also increase the flow of blood - and chemotherapy drugs - across the blood-brain barrier of laboratory rats.
This barrier limits the ability of substances like drugs from moving from the bloodstream into the brain - and therefore limits the effectiveness of chemotherapy.
Study author and neurosurgeon Dr Keith Black, chairman of the Department of Neurosurgery at Cedars-Sinai Medical Centre, commented: "This is the first study to show that oral administration of PDE5 inhibitors increases the rate of transport of compounds across the blood-brain tumour barrier and improves the effectiveness of the anti-tumour drug adriamycin in the treatment of brain tumours in a rat model."
The researchers investigated the impact of the ED drug vardenafil (Levitra) in 29 rats with brain tumours and have now published their findings in the journal Brain Research.
They found that rats treated with the anti-cancer drug adriamycin alone survived for an average of 42 days.
However, animals which also received the ED drug vardenafil survived for an average of 53 days, indicating that the additional drug helped to improve the delivery of the anti-cancer drug to the tumour.
Dr Black concluded: "The combination of vardenafil and adriamycin resulted in longer survival and smaller tumour size."
Black KL, Yin D, Ong JM, Hu J, Konda BM, Wang X, Ko MK, Bayan JA, Sacapano MR, Espinoza A, Irvin DK, & Shu Y (2008). PDE5 inhibitors enhance tumor permeability and efficacy of chemotherapy in a rat brain tumor model. Brain research, 1230, 290-302 PMID: 18674521