An appraisal of povidone-iodine and wound healing

Infection is one of the most frequent complications of wound healing despite the use of antibiotics and modern sterile technique; it accounts for considerable patient morbidity, discomfort, and prolonged hospitalization, and it must be avoided to permit proper healing. For this purpose, topical antiseptics have been employed for several years. Among these povidone-iodine formulations (polyvinylpyrrolidone iodine; PVP-I; e.g., Betadine preparations), which consist of a water-soluble complex of elemental iodine and a synthetic polymer, have a broad antimicrobial spectrum, and have not been reported to develop bacterial resistance. Because some reports have suggested that PVP-I may interfere with wound healing, a critical review of studies concerning PVP-I and wound healing was undertaken, with emphasis placed on in vivo models that replicate, as closely as possible, human wound healing. Four forms of PVP-I were evaluated: PVP-I solution, PVP-I skin cleanser/surgical scrub, PVP-I ointment, and PVP-I cream. PVP-I solutions had virtually no deleterious effect on wound healing: application of 10% PVP-I solution to rat, guinea pig, rabbit, or pig wounds did not reduce wound tensile strength or delay re-epithelialization. In three human studies, no significant difference in healing was observed for 1%, 5% or 10% PVP-I solution except for a slight delay during the first 24 hours after the application of 5% PVP-I solution in one study; healing was normal by 72 hours. PVP-I skin cleansers/surgical scrubs contain ammonium nonoxynol-4-sulphate and lauramide DEA which, like all detergents, can cause tissue damage and delay healing. This was substantiated by a guinea pig study in which the detergent component but no the antiseptic produced these effects. In human trials, no damage occurred if cleansing of the wound with PVP-I skin cleansers/surgical scrubs was followed by saline irrigation. These results are consistent with recommendations for promptly rinsing the wound with water to remove the detergent if detergent-containing PVP-I preparations are used for wound care. PVP-I ointment (10%) delayed wound closure inn rats during the fourth through tenth days post-treatment; however, during the next two weeks, healing was accelerated, and by day 24, healing was equal to the controls. No delays occurred when pigs or rabbits were tested. In human wounds, no delays occurred in healing, even when gel-type occlusive dressings were added to the wounds; in fact, bandage-wearing time was shortened in those patients treated with PVP-I ointment. PVP-I cream (5%) was also studied in humans; the cream formulation appeared to decrease healing time. Based on these studies, it can be concluded that povidone-iodine preparations do not have a deleterious effect on wound healing.