Xanthinol is a drug prepared from theophylline used as a

vasodilator Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, ...

. It is most often used as the salt with

niacin Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variet ...

(nicotinic acid), known as xanthinol nicotinate.

References

Vasodilators Xanthines Diols {{cardiovascular-drug-stub