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Causality: well established
Causality assessment · Causality: well established
Ivermectin and Neurotoxicity: is the FAERS signal real?
A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.
Ivermectin ↔ Neurotoxicity
n=246 co-reports · PRR 17.3 · ROR 17.9
Ivermectin is an antiparasitic used for onchocerciasis, strongyloidiasis, and scabies; neurotoxicity — drowsiness, confusion, ataxia, and in heavy infection a post-treatment encephalopathy — reflects massive release of parasite antigen or drug crossing a damaged blood-brain barrier, and coma carries 246 co-reports here (PRR 17.3). Risk is greater in Loa loa and in onchocerciasis co-infection, where the label advises caution.
Regulatory basis: ivermectin prescribing information — neurotoxicity caution in Loa loa; post-treatment encephalopathy literature.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Coma follows treatment |
| Strength | met | PRR 17.3, large |
| Consistency | met | Reproduced across case series |
| Specificity | met | Fairly specific to heavy microfilaraemia |
| Biological gradient | partial | Related to parasite burden |
| Plausibility | met | Antigen release and drug CNS toxicity |
| Coherence | met | Fits the pharmacology |
| Experiment | n/a | Too rare for trial detection |
| Analogy | met | Analogous to other antifilarial reactions |
This table is this page's own qualitative read of the literature cited above, not an automated or citation-gated assessment — see the note at the bottom of this page.
✗ No ClinicalTrials.gov results-posting trial in the top search hits for ivermectin captured neurotoxicity as a tracked adverse event in a usable structure. Post-treatment neurotoxicity is rare and restricted to high-microfilaraemia patients, so trials could not capture it as a coded event.