Does ivermectin affect metabolism or efficacy of systemic corticosteroids used as chemo supportive care?
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Executive summary
Available sources show no clear pharmacokinetic interaction between ivermectin and systemic corticosteroids such as prednisone or dexamethasone, and interaction checkers list no direct interaction between ivermectin and prednisone (no interactions found on Drugs.com) [1]. Clinical guidance and cohort studies instead focus on the opposite clinical issue: corticosteroids increase risk of Strongyloides hyperinfection, and many institutions recommend screening or empiric ivermectin prophylaxis when high‑dose steroids are given to at‑risk patients (WHO guidance; retrospective and protocol implementation studies) [2] [3] [4].
1. No signal that ivermectin changes corticosteroid metabolism
Drug interaction databases consulted in the available record do not report that ivermectin alters prednisone metabolism or the efficacy of systemic corticosteroids; Drugs.com lists “no interactions found” between ivermectin and prednisone in its interaction checker [1], and general ivermectin interaction listings enumerate drug interactions but do not identify a steroid‑metabolism effect for corticosteroids in the cited materials [5] [6]. Available sources do not mention direct CYP‑mediated reduction in steroid levels caused by ivermectin.
2. Clinical concern runs the other way: steroids increase parasitic risk
The dominant theme across guidelines and studies is that systemic corticosteroids—by suppressing host immunity—can precipitate life‑threatening Strongyloides hyperinfection or disseminated disease; that risk motivates empiric ivermectin treatment or screening before or during high‑dose steroid therapy in endemic or at‑risk populations (WHO advisory; AJTMH review; retrospective cohorts) [2] [7] [3]. Institutions implemented protocols giving ivermectin to many patients receiving high‑dose corticosteroids for COVID‑19 to avoid this complication [4].
3. Evidence base: prophylaxis and cohort data, not drug‑drug pharmacology
The studies and guidance available are clinical and epidemiologic: retrospective cohort analyses and protocol implementation reports evaluate ivermectin’s role in preventing Strongyloides complications when corticosteroids are needed, rather than randomized trials testing ivermectin’s effect on steroid pharmacokinetics [3] [4]. WHO explicitly recommends considering presumptive ivermectin treatment for people from endemic areas before starting corticosteroids [2]. These pieces of evidence address clinical outcomes, not biochemical interaction.
4. Safety signals and case reports—complex causality
There are isolated case reports and pharmacovigilance entries noting neuropsychiatric events where both ivermectin and corticosteroids were given off‑label (a Reactions Weekly report links hyperactive delirium/psychosis to combined ivermectin and prednisone in one COVID‑19 case) [8]. Such reports do not establish a causal pharmacokinetic interaction; they document adverse events in polypharmacy contexts where attribution is uncertain. Available sources do not present controlled data showing that ivermectin potentiates steroid toxicity or vice versa [8].
5. How major societies position ivermectin vs. steroids (conflicting roles)
In COVID‑19 care guidelines cited, professional societies strongly recommend systemic corticosteroids for critically ill patients because of mortality benefit, and they advise against using ivermectin for COVID‑19 outside trials because of low certainty of benefit — thus positioning steroids and ivermectin in fundamentally different roles (steroids: proven benefit in severe COVID; ivermectin: not recommended for COVID use) [9]. This reflects differing evidence thresholds and intended uses, not an interaction between the drugs.
6. Practical takeaway for clinicians and patients
For clinicians: do not presume ivermectin will alter corticosteroid metabolism based on current reports — check interaction databases (Drugs.com/DrugBank/Medscape) which show no documented steroid‑metabolism interaction in the supplied sources [1] [5] [6] [10]. For patients from or with exposure to Strongyloides‑endemic regions who will receive high‑dose or prolonged corticosteroids, follow guidance to screen or give presumptive ivermectin to prevent hyperinfection (WHO, AJTMH, cohort reports) [2] [7] [3] [4].
7. Limits, uncertainties, and what’s not in the record
The sources provided do not include detailed pharmacokinetic studies that would rule out subtle metabolic interactions between ivermectin and specific corticosteroids (available sources do not mention randomized PK studies of ivermectin plus corticosteroids). They also do not cover every steroid formulation/dose or interactions with cancer chemotherapy regimens used for supportive care beyond the COVID‑era cohort and guidance documents cited (not found in current reporting). If precise PK data are required for a specific steroid (e.g., dexamethasone at high chemo‑supportive doses), targeted pharmacologic studies or drug‑interaction monographs beyond these sources would be needed.
Bottom line: current reporting and interaction checkers in the supplied sources show no documented ivermectin‑mediated reduction of systemic corticosteroid efficacy, while multiple clinical authorities warn that systemic corticosteroids increase the risk of severe Strongyloides disease and therefore recommend screening or empiric ivermectin in at‑risk patients [1] [2] [3] [4] [9].