Does long-term ivermectin use affect liver or kidney function?
Executive summary
Available clinical and pharmacovigilance reporting shows ivermectin is generally well tolerated at standard single doses but has been associated with rare liver injury and occasional transient liver enzyme rises; kidney injury is much less commonly reported and clinical trials did not find kidney-specific side effects [1] [2] [3]. Animal studies and small experimental series report liver and renal biochemical changes after repeated or high-dose exposure, raising plausibility for organ effects with long or excessive dosing — but large human long‑term safety studies are not described in the available material [4] [5] [6].
1. What the clinical safety record says: mostly safe but not risk‑free
Regulatory and clinical summaries describe ivermectin as “relatively free of toxicity” at standard single doses and report only low rates of transient aminotransferase elevations after single‑dose therapy, but they also document very rare cases of clinically apparent drug‑induced liver injury (DILI) following ivermectin [7] [1]. A pharmacovigilance analysis found cases of hepatitis, hepatocellular injury and cholestasis reported when ivermectin was used — including in some COVID‑19 users — indicating real, if uncommon, hepatic risk [2]. Several clinical sources and drug guides therefore advise caution and to stop the drug if signs of liver injury occur [3] [1].
2. Kidney effects in humans: uncommon in trials, but expert caution exists
Clinical trial summaries and drug references state that kidney‑specific side effects were not prominent in trials and that nephrotoxicity was not a reported common outcome in human studies [3] [8]. However, infectious‑disease experts warned during the COVID era that indiscriminate or high‑dose use could potentially harm liver or kidneys — a cautionary stance reflecting limited trial data on off‑label, repeated, or high‑dose regimens rather than documented widespread kidney injury [9] [10]. MedicalNewstoday and other drug guides likewise report no clear kidney adverse‑effect signal from clinical trials while still advising monitoring in patients with preexisting organ disease [3] [11].
3. Animal and small experimental studies: repeated/high doses show organ changes
Multiple animal studies find biochemical and histological changes in liver and kidney after repeated or high‑dose ivermectin, including altered liver enzymes, increased urea/creatinine, and renal histopathology; some studies also show mitigation of damage with antioxidants [4] [5] [6]. These findings establish biological plausibility that prolonged or excessive exposure can affect liver and kidney tissues, but animal dosing and human clinical contexts differ and cannot be equated directly [4] [5].
4. Context: dose, duration, underlying disease and drug interactions matter
Reports of liver injury frequently involve nonstandard scenarios — multiple doses, high doses, concomitant medications, or use outside approved indications (e.g., self‑treatment for COVID) — and drug interactions or host factors (genetic variants in drug transport/metabolism) have been implicated in serious neurologic adverse events in some trials [12] [2]. Regulatory bodies emphasize that ivermectin is approved for specific parasitic diseases at weight‑based single or short‑course dosing; longer or higher dosing regimens used off‑label were not well studied in available reporting [3] [13].
5. How common and how severe are these problems?
Available pharmacovigilance and case reports indicate liver injury is rare but can be severe (jaundice, cholestasis, biopsy‑proven DILI in case reports), while kidney complications in humans appear uncommon in published trials [14] [2] [3]. The exact incidence of serious hepatic or renal adverse events with long‑term ivermectin in humans cannot be quantified from the supplied sources; they describe scattered case reports and pharmacovigilance signals rather than large prospective long‑term safety cohorts [2] [1].
6. What this means for patients and clinicians
For approved, short‑course, weight‑based therapy for parasitic infections, ivermectin’s human safety record is favorable though clinicians should monitor liver enzymes if clinical concern arises and avoid uncontrolled high‑dose or prolonged self‑administration [7] [1] [3]. For repeated, long‑term, or off‑label use (for example during the COVID‑19 period), available sources document warnings from experts and case reports of hepatic injury, and animal studies show organ changes — reasons to require medical supervision, baseline organ assessment, and caution about drug interactions or genetic susceptibilities [9] [2] [4].
Limitations: available sources do not include large, dedicated human studies of “long‑term” ivermectin exposure in otherwise healthy people, so incidence estimates and definitive causation for chronic renal or hepatic disease are not established in the current reporting (not found in current reporting).