For Safer Use of Ivermectin in All Patients

Abstract

The difficult experience of treating scabies in an elderly hospital reaffirmed my determination and responsibilities as a pharmacist. In 2000, there was no effective treatment for scabies in Japan. With the Japan Pharmaceutical Association as well as the Japanese Dermatological Association, the indication of ivermectin which is the intestinal fecal nematode was expanded for scabies. Since it was found that the administration of ivermectin through a tube to patients who could not take it orally had a dose loss of 50% depending on the injection method, an appropriate administration method was proposed. However, the oral administration of ivermectin has side effects including systemic liver damage, and external preparations require labor for systemic application, and recurrence from unapplied areas is also a problem. Therefore, we devised a whole-body bathing, in which patients are immersed in a fluid that contains ivermectin. The repeated ivermectin bathing three times a week cured scabies and has no problematic side effects in the clinical trial, suggesting that this method is a safer treatment. Next, in Okinawa, phenothrin-resistant head lice infestation was prevalent, and no medical drug for this infestation is available in Japan yet. Hence, to address this situation, we conducted a clinical trial to investigate the efficacy and safety of a combination regimen of 5% topical phenothrin and the unapproved 0.5% topical ivermectin. Consequently, 92% and 100% effectiveness were obtained in Okinawa and Tsukuba, respectively. As a result, we were able to conduct research aimed to maximize the safety and effectiveness of ivermectin in Japan.