Ivermectin exposures reported to the Poisons Information Helpline in South Africa during the COVID-19 pandemic

Background. Ivermectin is an antiparasitic drug that has shown in vitro activity against COVID-19. Clinical studies supporting ivermectin for COVID-19 prevention and treatment are conflicting, with important limitations. Public support for ivermectin is significant, with extensive off-label use despite the conflicting views on its efficacy. Ivermectin tablets and injectable formulations are not registered in South Africa for human use by the South African Health Products Regulatory Authority. The National Department of Health does not currently recommend the use of ivermectin for COVID-19. Objectives. To describe cases of ivermectin exposure reported to the Poisons Information Helpline of the Western Cape (PIHWC) before and after publication of the drug's in vitro activity against SARS-CoV-2. Methods. In a retrospective review, ivermectin-related calls reported to the PIHWC from 1 June 2015 to 30 June 2020 (period 1) were compared with calls received from 1 July 2020 to 31 July 2021 (period 2), dichotomised according to the first publication indicating ivermectin activity against SARS-CoV-2. Results. Seventy-one cases were screened, and 65 were included for analysis; 19 cases were reported during period 1 and 46 during period 2. During period 2, 25 ivermectin cases (54.3%) were related to COVID-19 use. Of these, 24 cases (52.2%) involved veterinary preparations, 3 (6.5%) human preparations and 19 (41.3%) unknown preparations. Fourteen cases (73.7%) during period 1 and 30 (65.2%) during period 2 were reported to be symptomatic. The most common organ systems involved were the central nervous (n=26 cases; 40.0%), gastrointestinal (n=18; 27.7%), ocular (n=9; 13.8%) and dermatological (n=5; 7.7%) systems. Conclusion. Ivermectin-related exposure calls increased during study period 2, probably as a result of ivermectin being used as preventive and definitive therapy for COVID-19 in the absence of robust evidence on efficacy, dosing recommendations or appropriate formulations.