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

Background: 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.

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

Methods: 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.

Results: 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.

Conclusion: 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.