OpenClaim

Istradefylline Side Effects

The most commonly reported side effects of istradefylline include death, hallucination, and dyskinesia, based on 5,778 FDA adverse event reports from 2007 to 2025. 10.7% of reports found the drug to be ineffective.

Istradefylline side effects

Percentages show how often each reaction appears relative to total reports for istradefylline.

1
Death11.7%677
2
Drug Ineffective10.7%617
3
Hallucination10.3%595
4
Dyskinesia8.3%477
5
Condition Aggravated7.7%447
6
Dizziness7.2%416
7
Product Dose Omission Issue6.1%352
8
Constipation6.1%351
9
Fall5.7%330
10
Tremor4.5%259
11
Therapy Non-responder4.4%252
12
Insomnia3.9%225
13
Fatigue3.5%200
14
Nausea3.4%195
15
Parkinson^s Disease3.1%177

These are voluntary reports and do not establish that istradefylline caused these reactions.

Report severity

43.3%Serious2,500 reports
12.7%Hospitalizations736 reports
15.2%Fatal876 reports

Seriousness is determined by the reporter, not by OpenClaim.

Istradefylline drug interactions

Other drugs that appear in adverse event reports alongside istradefylline. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Levodopa6.1%350
2
Pimavanserin6.1%350
3
Carbidopa3.8%217
4
Amantadine1.5%85
5
Apomorphine-hydrochloride0.8%49
6
Entacapone0.7%42
7
Opicapone0.5%29
8
Rotigotine0.5%27
9
Ropinirole-hydrochloride0.5%27
10
Rasagiline-mesylate0.5%27
11
Droxidopa0.4%25
12
Zonisamide0.4%24
13
Pramipexole-dihydrochloride0.4%22
14
Foscarbidopa0.3%19
15
Foslevodopa0.3%19

Taken alongside

1
Carbidopa42.6%2,461
2
Levodopa40.3%2,326
3
Ergocalciferol13.5%782
4
Amantadine11.6%668
5
Aspirin10.4%599
6
Atorvastatin-calcium9.4%542
7
Levothyroxine-sodium7.9%456
8
Rasagiline-mesylate7.5%435
9
Gabapentin7.1%412
10
Pramipexole-dihydrochloride6.8%391
11
Entacapone6.5%378
12
Acetaminophen6.4%369
13
Omeprazole6.3%365
14
Clonazepam6.3%364
15
Ropinirole-hydrochloride6.3%362

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports istradefylline side effects

6.0% of istradefylline adverse event reports involve female patients and 8.8% involve male patients. The largest age group is elderly at 77%. These figures reflect who reports side effects, not underlying risk.

Sex

Female6.0%
Male8.8%
Unknown85.2%

Age group

< 20.2%
2–110.0%
12–170.0%
18–6422.9%
65+76.9%

What is istradefylline used for

Conditions and purposes for which patients were taking istradefylline when the adverse event was reported.

Autonomic Nervous System ImbalanceAbuliaAdjuvant TherapyAutonomic NeuropathyBenign Prostatic HyperplasiaBlood DisorderCardiac DisorderCerebral Artery OcclusionCerebral Artery StenosisCerebral PalsyDementiaDementia Alzheimer^s TypeDyskinesiaDelusionDementia

Showing 15 of 72 indications

Istradefylline brand names and reporting trend

Istradefylline is sold under the brand name Nourianz.

Brand names

Nourianz293

Quarterly reports (20072025)

201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking istradefylline with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.