Ask the Experts

[as published in the VHL Family Forum, March 1996]

Question: I have a blood clotting problem for which my doctor has prescribed Coumadin. Should I be concerned about the effects of Coumadin on tumor growth in VHL? -- Clark C., Washington

Answer: Coumadin (warfarin) is a "blood thinner" that predisposes those taking it to bleed. It is used in people who have artificial heart valves, thrombophlebitis, pulmonary embolus, myocardial infarction, atrial fibrillation, etc. Coumadin interacts with many other drugs and has several side effects. The primary side effect of Coumadin is the predisposition to bleed. Coumadin should be used when its benefit outweighs its risk of side effects.

VHL tumors are generally highly vascular (hemangioblastoma, angiomas, renal carcinoma) but they usually do not spontaneously bleed. The predisposition to bleed caused by Coumadin could be a problem with VHL tumors, but it is hard to know exactly how much. As usual, one would have to carefully weigh risks versus benefits, and act accordingly. I personally do not want to use Coumadin in a VHL patient unless there was a very good reason to do so, that is, there were unequivocal benefits.

-- Col. J. M. Lamiell, M.D., Chief, Clinical Investigation Regulatory Office, U.S. Army Medical Education Department, Fort Sam Houston, Texas.