Understanding Perceptions and Experiences on Acceptability of Oral Ivermectin, Topical Permethrin, and their Combination in the Treatment of Adult Filipino Patients with Scabies: A Multiple Case Study

Abstract

Background and objective: Oral ivermectin, a broad-spectrum anti-parasitic drug, alone or in combination with permethrin, may be a cheaper and more convenient alternative drug to topical permethrin alone in the treatment of classic scabies. There are no previous studies on the treatment acceptability of the three interventions among individual patients with scabies in the Philippines.The purpose of this study was to understand the experiences and perceptions on treatment acceptability for oral ivermectin, topical permethrin or combination treatment among patients with scabies using the multiple-case study approach.

Methods: We conducted a qualitative multiple case study among adult Filipino patients with classic scabies who were prescribed oral ivermectin, topical permethrin or its combination at a government tertiary hospital dermatology outpatient clinic from December 2022 to September 2023. Semi-structured interviews were used as the primary source of data and analyzed together with chart reviews, Dermatology Life Quality Index (DLQI) scores, and clinical images. Interviews were transcribed, coded, and triangulated with other secondary data. A three-person research team employed a reflexive and iterative process of familiarization, coding, and thematic analysis using a modified Theoretical Framework of Acceptability (TFA) to generate case descriptions, within-case analyses, and cross-case syntheses.

Results: The acceptability of scabies treatments (permethrin, ivermectin, and combination therapy) was generally positive. Permethrin, used in three patient cases, was generally perceived as effective but itch relief varied. The burden of whole-body application of permethrin was context-dependent, influenced by living arrangements and family support. Perceived affordability of permethrin was linked to socioeconomic status. Ivermectin, used by one patient case, was perceived as highly effective with no side effects. Its single dose use did not interfere with patient routine. Combination therapy was also considered effective but potential antagonistic effects and the cost of adding permethrin made it less preferred. Reluctance in taking oral pills was noted. All patients valued medical advice and deferred to their physicians for treatment decisions.

Conclusion and recommendations: All three treatment options were considered effective and safe. Patients generally preferred permethrin over oral ivermectin due to its topical nature and perceived lower side effects. However, affordability and logistical challenges, especially for large households and low-income families, were noted with permethrin. Oral ivermectin elicited hesitation due to its controversial role in COVID-19 and veterinary use. Concerns about added costs and potential antagonism in combination therapy were raised. Despite these considerations, patients ultimately relied on physicians for treatment decisions. This study underscores the importance of understanding patient perspectives, experiences, and the patient-physician relationship in choosing scabies interventions. Addressing patient concerns, providing education, and ensuring ease of use and affordability can enhance treatment acceptability and adherence for better outcomes.

Keywords: acceptability; case study; ivermectin; permethrin; qualitative research; scabies.

Figure 1

Modified Theoretical Framework of Acceptability (TFA). Note: Prospective – prior to participating in the intervention; Concurrent – while participating in the intervention; Retrospective – after participating in the intervention. Source: 7 domains and definitions by Sekhon et al., 2017; an 8^th domain on accessibility was added by this study.