Phenol as a novel sclerosing agent: A safety and efficacy study on experimental animals

Varicose and ectatic cutaneous vessels are common chronic conditions that might need surgical treatment. There are several treatment modalities, but all can cause complications and have significant recurrence rates. A new effective and safe treatment with low or no recurrence is needed. Phenol seems to be a potential therapeutic agent.

To assess the efficacy and safety of phenol as a sclerosing agent in the treatment of varicose veins and other vascular ectatic conditions.

The dorsal ear veins of white New Zealand rabbits were injected with 0.1 ml of a sclerosing agent. Four experimental groups were used to test the sclerosant efficacy of different concentrations of phenol (1%, 5%, 20% and 50%). Sodium tetradecyl sulphate (STS), a commonly used sclerosing agent, was used as a positive control, while normal saline was used as a negative control. The blood vessels of the treated ears were photographed before and 1 h, 2 days, 8 days and 45 days after treatment. Biopsies from the treated areas were obtained for histologic examinations.

A concentration of 1% phenol was too low to cause significant vascular changes, whereas a concentration of 5% phenol caused 90% lumen narrowing. Interestingly, 1% STS only caused 25% lumen narrowing. Concentrations of 20 and 50% phenol caused 100% lumen narrowing but caused haemorrhage and necrosis. Toxicity monitoring showed no apparent haematologic, cardiac, pulmonary, hepatic or renal toxicity associated with the concentrations of phenol used in this study.

A concentration of 5% phenol appears to be a potent and safe sclerosing agent for ectatic small vessels. This provides a significant new therapeutic option, which may eventually advance to the clinic and have an impact on the treatment of patients suffering from varicose veins and other vascular ectatic conditions.