Treatment of Palmar Plantar Erythrodysesthesia (PPE) With Topical Sildenafil

Subjects will be given 2 types of topical creams, one containing 1% sildenafil and one containing placebo control. Subjects will be randomized to apply sildenafil cream to either the right or left hand/foot; placebo cream will be applied to the opposite hand/foot. The cream will be supplied to subjects with proper labeling to indicate right and left application assignment. Cream will be applied to each affected hand/foot two times per day.