The use of 5,6 benzo-[alpha]-pyrone (coumarin) and heating by microwaves in the treatment of chronic lymphedema of the legs.

Sixty patients with leg lymphedema from a variety of etiologies were divided into randomized two groups, matched by Grade, duration, age, sex, and cause of lymphedema. Using a double-blind format, one group received 5,6 benzo-[alpha]-pyrone (coumarin 1,2 benzopyrone, 400 mg/day) for six months; the other received a placebo. For the next six months, both groups received a standardized regimen of heat (using microwaves) coupled with compression garments. Benzopyrone produced approximately 20% reduction in the volume (p = 10(-4)) and improvement in circumferences and tonometry (p = 10(-5) and 10(-7)). Symptoms (feelings of swelling, pain, heaviness and loss of mobility) were also significantly improved (p = 0.03 to 10(-7)). During the second six months, when microwave heat therapy was added to drug therapy, the patients who had previously received the placebo showed significant improvement (p = 0.03 to 10(-9)) in signs and symptoms of lymphedema. Some, but not all, of the group that was receiving benzopyrones were also significantly improved by heat therapy (p = 0.8 to 0.002). Taking benzopyrones for 12 months plus heat treatment for six months was significantly better, for some criteria, than the placebo plus heat therapy (p = 0.7 to 0.04). On the other hand, heat plus either placebo or benzopyrone was often significantly better than either the active or inactive drug without heat (p = 0.8 to 10(-9)).