Causality assessment · Causality: well established

Levodopa and Dyskinesia: is the FAERS signal real?

n=760 co-reports · PRR 33.3 · ROR 35.5

Levodopa side-effect profile All assessments See in the full list

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.

Causality: well established

Levodopa ↔ Dyskinesia

n=760 co-reports · PRR 33.3 · ROR 35.5

Levodopa is the most effective treatment for Parkinson's disease, but after years of therapy most patients develop levodopa-induced dyskinesias — involuntary choreiform movements tied to peak drug levels — reflecting pulsatile dopamine-receptor stimulation (760 co-reports here, PRR 33.3). The effect is so characteristic of chronic levodopa use that reducing the dose, adding a COMT or MAO-B inhibitor, or using continuous delivery are the standard management strategies.

Regulatory basis: levodopa/carbidopa prescribing information — dyskinesia; Parkinson's-disease treatment literature.

Bradford Hill viewpoint	Status	Note
Temporality (necessary)	met	Dyskinesias emerge after months to years
Strength	met	PRR 33.3, large
Consistency	met	Universally reproduced in practice
Specificity	met	Highly specific to dopaminergic therapy
Biological gradient	met	Related to dose and duration
Plausibility	met	Pulsatile dopamine-receptor stimulation
Coherence	met	Fits the pharmacology
Experiment	met	Trial and registry data support it
Analogy	met	Analogous to dopamine-agonist dyskinesia

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 Placebo- and Ropinirole-Controlled Study for SPM 962 in Advanced Parkinson's Disease Patients (NCT01628926)

Adverse event	SPM 962 (n=168) · Ropinirole (n=167) · Placebo (n=85)
Dyskinesia	27/168	23/167	1/85

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 →