Lactulose in vincristine-induced constipation.

Constipation which is resistant to the usual range of laxatives is a troublesome undesirable effect of vincristine. Lactulose in doses up to 25 ml thrice daily proved to be a simple and effective treatment in six patients with refractory vincristine-induced constipation, and a successful prophylactic in two other patients. Palatable, and without any serious undesirable effects, lactulose can improve the quality of life for patients with a malignant tumour which is responsive to vincristine.