Sclerotherapy / Asclera® is considered the medical treatment of choice used to eliminate varicose veins and spider veins. The treatment is minimally invasive. The procedure also can improve related symptoms such as aching, swelling, burning, and night cramps. Treated veins tend to fade within a few weeks, although occasionally it may take up to two months to see the full results. In some instances, several sclerotherapy treatments may be needed.