Oseltamivir and Neuropsychiatric events: is the FAERS signal real?
Oseltamivir ↔ Neuropsychiatric events
Oseltamivir is a neuraminidase inhibitor for influenza; neuropsychiatric events — delirium, confusion, and in rare cases self-injury — have been reported, particularly in children and adolescents (delirium 66 co-reports here, PRR 5.1). The reports prompted regulatory review and warning label changes, but causality remains uncertain because influenza itself can cause encephalopathy and delirium, and controlled trials have not confirmed an excess.
Regulatory basis: oseltamivir prescribing information — neuropsychiatric events; regulatory reviews of delirium/self-injury.
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | partial | Onset during treatment |
| Strength | met | PRR 5.1, moderate |
| Consistency | met | Reported across case series |
| Specificity | not established | Not specific to oseltamivir |
| Biological gradient | not established | Cannot exclude influenza encephalopathy |
| Plausibility | not established | No established dose relationship |
| Coherence | partial | Mechanism debated |
| Experiment | not established | Not reproduced in trials |
| Analogy | partial | Debated analogy to influenza-related delirium |
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.
✓ Trial evidence found — A Study of Intravenous Zanamivir Versus Oral Oseltamivir in Adults and Adolescents Hospitalized With Influenza (NCT01231620)
| Adverse event | Intravenous (IV) Zanamivir 300mg Twice Daily (n=201) · Intravenous (IV) Zanamivir 600mg Twice Daily (n=209) · Oral Oseltamivir 75mg Twice Daily (n=205) | ||
|---|---|---|---|
| Delirium febrile | 0/201 | 0/209 | 1/205 |
| Encephalopathy | 1/201 | 0/209 | 1/205 |
Post-marketing signal terms appear in this trial's posted adverse-event tables; per-arm counts shown as affected/at-risk. View on ClinicalTrials.gov →