The 2020 American College of Obstetricians and Gynecologists (ACOG) committee opinion on topical hemostatic agents in obstetric and gynecologic surgery notes that topical caustic agents include aluminum chloride, ferric subsulfate 20% (Monsel’s solution), silver nitrate, and zinc chloride paste. The guidance explains that these agents coagulate proteins, resulting in tissue necrosis and eschar formation, which promotes thrombus formation and hemostasis. Additionally, these agents are commonly used on the cervix and vagina but are not recommended for intra-abdominal use. Of note, the guidance does not provide comparative data for these caustic agents, and the agents are not ranked in terms of effectiveness. [1]
Available review articles suggest that several topical caustic and astringent agents are used to achieve hemostasis in dermatologic and minor surgical settings. These agents include aluminum chloride, ferric subsulfate 20% (Monsel’s solution), ferric sulfate, silver nitrate, zinc chloride, alum (aluminum potassium sulfate), calcium sulfate, tannic acid, and Negatol solution. Evidence indicates that they primarily act by coagulating proteins, leading to tissue necrosis, eschar formation, and thrombus formation, and some also have astringent effects that produce superficial or localized coagulation. Aluminum chloride is reported to be used at concentrations of 5% to 25% and generally does not cause pigment changes on the skin or tissue. Ferric subsulfate is described as a highly acidic brown solution applied as a paste or liquid; it can denature proteins but may also stain skin, teeth, and soft tissues. Ferric sulfate appears to have lower astringent properties, and healing may be faster than with aluminum chloride, although higher concentrations can temporarily pigment tissue. Silver nitrate is applied to superficial wounds, including pyogenic granulomas, and forms a thin eschar that usually sloughs off within several days, but it may result in permanent pigmentation. Zinc chloride, used at concentrations of 8% to 40%, is escharotic and may cause permanent tissue injury; its current use is uncommon. Alum and aluminum sulfate have been reported to provide hemostasis in gingival tissues with fewer systemic effects than concentrated epinephrine. Calcium sulfate appears to be biocompatible, resorbable, and associated with minimal inflammatory response. Lastly, tannic acid and Negatol solution are noted to have limited hemostatic effects. Of note, the reviews do not provide comparative data; however, authors suggest that potential differences among these agents relate to tissue toxicity, risk of pigmentation, and concentration-specific effects. [2], [3]
A 2020 investigation aimed to evaluate three chemical cautery solutions, ferric subsulfate, silver nitrate, and aluminum chloride hexahydrate, for their effects on time to hemostasis, pain upon application, and associated pigmentary changes (see Table 1). Twelve patients with six or more skin tags on the bilateral neck or axilla participated in the study, with two skin tags treated with each cautery solution. The time to hemostasis and pain response were recorded during the procedure, and at a two-week follow-up, patient satisfaction and pigmentary changes were assessed using a survey and digital photography. The results showed no significant differences in time to hemostasis among the three solutions. Pain responses differed significantly, with aluminum chloride hexahydrate and ferric subsulfate producing lower pain scores compared to silver nitrate. Pigmentary changes were observed in 25% of sites treated with ferric subsulfate, 17% with aluminum chloride, and 50% with silver nitrate, although this difference was not statistically significant. The study concluded that these chemical cautery solutions differ in pain upon application and the likelihood of pigmentary changes, which may be relevant factors to consider when selecting a cautery agent. [4]