Comparative Effectiveness of Oral Ivermectin, Topical Permethrin, and Its Combination in the Treatment of Scabies

Poster
2024 Prague [Global Evidence Summit]
Genuino R1, Cagayan M2, Capule F3, Garcia Jr F4, Ladia M5, Santos M6, Yabes A2, Batac M7
1Department of Anatomy, University of the Philippines Manila, Manila, Metro Manila, Philippines; Makati Medical Center Department of Dermatology, Makati, Metro Manila, Philippines
2Department of Pharmacology and Toxicology, College of Medicine, University of the Philippines Manila, Manila, Metro Manila, Philippines
3Department of Pharmacy, College of Pharmacy, University of the Philippines Manila, Manila, Metro Manila, Philippines
4Department of Health Policy and Administration, College of Public Health, University of the Philippines Manila, Manila, Metro Manila, Philippines
5Institute of Clinical Epidemiology, National Institutes of Health, University of the Philippines Manila, Manila, Metro Manila, Philippines
6Mapua School of Health Sciences, Makati, Metro Manila, Philippines
7Department of Dermatology, College of Medicine, University of the Philippines Manila, Manila, Metro Manila, Philippines

BACKGROUND:

Scabies, caused by Sarcoptes scabiei var. hominis, is a prevalent and burdensome skin disease in the Philippines, ranking second in disability. Recognized as a neglected tropical disease (NTD) by the WHO, scabies management is targeted for inclusion in universal healthcare programs worldwide by 2030. Current treatment involves topical neurotoxic drugs like permethrin, but issues such as expense and inconvenience hinder compliance. Oral ivermectin, recommended by the WHO only recently, is more cost-effective and easier to administer but is considered a second-line option in clinical practice guidelines. This research aimed to determine the comparative efficacy, safety, cost-effectiveness, and acceptability of oral ivermectin, alone or in combination with topical permethrin, versus topical permethrin alone, in the treatment of classic scabies among Filipino patients.

METHODS:

This 4-part study was conducted from July 2021 to September 2023 and aimed to compare the efficacy, safety, cost-effectiveness, and acceptability of oral ivermectin alone or in combination with topical permethrin versus topical permethrin alone for treating classic scabies among Filipino patients. Quantitative methods included a systematic review and network meta-analysis of 38 randomized controlled trials (RCTs) and a pharmacoeconomic evaluation using decision tree modeling. Qualitative methods involved a multiple case study of patient experiences and perceptions and in-depth interviews with physicians.

RESULTS:

There seems to be comparable efficacy between oral ivermectin and permethrin, with limited evidence favoring the combination ivermectin/permethrin regimen. Adverse events were minor, and cost-effectiveness analyses favored ivermectin-based regimens over permethrin. Patient and physician perspectives supported the effectiveness of all treatments, with oral ivermectin recognized as safe but underutilized.

CONCLUSION:

Evidence synthesis suggests that oral ivermectin, especially in combination with permethrin, could be a viable and cost-effective alternative for scabies treatment in the Philippines. The optimal dosing regimen, safety in specific populations, and factors influencing treatment choice need further exploration. Recommendations include advocating for oral ivermectin inclusion in regulatory guidelines and national formulary, considering it as a first- or second-line treatment, and conducting further research, including mixed-methods designs, to confirm efficacy, safety, and cost-effectiveness in different settings. Shared decision-making, considering ethical, logistical, socioeconomic, and psychological aspects, is crucial in implementing effective scabies control programs.