Istradefylline
NOURIANZ
What it isAdenosine A2A receptor antagonist; off episodes in Parkinson disease.
Why this oneIt reduces off time without directly stimulating dopamine receptors, offering a mechanistically distinct levodopa add-on.
What limits itDyskinesia can worsen; hallucinations and impulse-control disorders occur, and CYP3A4 modifiers alter exposure.
FDA-approved for
- Parkinson OFF episodes (2019)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Adjunct to levodopa/carbidopa for Parkinson's 'off' episodes | Adult | 20 mg QD | 20 mg QD | 40 mg QD |
| Same, in patients smoking ≥20 cigarettes/day | Adult (heavy smoker) | 40 mg QD | 40 mg QD | 40 mg QD |
Renal No adjustment needed
Hepatic Moderate impairment (Child-Pugh B): max 20 mg QD; avoid in severe impairment.
Instructions
- May be taken with or without food
- Initial dose titration is not required
Cautions
- May cause or worsen dyskinesia
- Hallucinations/psychotic behavior — avoid in major psychotic disorder
- Impulse control/compulsive behaviors
Adverse reactions
- Dyskinesia
- Dizziness
- Constipation
- Nausea
- Hallucination
- Insomnia
Pregnancy May cause fetal harm (animal teratogenicity at clinically relevant exposures); no adequate human data.
Lactation No human data; present in rat milk.
NO BOXED WARNINGS
Principal riskWorsening dyskinesia; hallucinations
Cost, est. cash$300–$5,000/month
Generic entry2027 est.
Classes and tags
Clinical profile
Legacy pregnancy categoryNot assigned — PLLR-era drug
Defining liabilityOrthostasis, hallucinations, dyskinesia and impulse-control symptoms; abrupt withdrawal can be hazardous.
Mechanism of action: Istradefylline ballicule
Open Istradefylline in the interactive console ↗
Memory aids: mascots and interaction avatars
tremor/spilling coffee → Parkinson’s medication
coffee → similar structure to caffeine, but not a methylxanthine
Manuel Noriega
