Istradefylline Side Effects

Medically reviewed by Drugs.com. Last updated on Oct 15, 2024.

Applies to istradefylline: oral tablet.

Serious side effects of istradefylline

Along with its needed effects, istradefylline may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking istradefylline:

More common side effects

• seeing, hearing, or feeling things that are not there
• twitching, twisting, uncontrolled repetitive movements of tongue, lips, face, arms, or legs

Less common side effects

• actions that are out of control
• anxiety
• attack, assault, force
• confusion
• confusion as to time, place, or person
• delusions of persecution, mistrust, suspiciousness, or combativeness
• dry mouth
• false beliefs that cannot be changed by facts
• hyperventilation
• increased sexual urges
• irregular heartbeats
• irritability
• restlessness
• shaking
• shortness of breath
• talking, feeling, and acting with excitement
• trouble sleeping
• unusual excitement, nervousness, or restlessness

Other side effects of istradefylline

Some side effects of istradefylline may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common side effects

• difficulty having a bowel movement (stool)
• nausea

Less common side effects

• decreased appetite
• diarrhea
• dizziness
• rash

For healthcare professionals

Applies to istradefylline: oral tablet.

General adverse events

The most commonly reported adverse reactions have included dyskinesia, dizziness, constipation, nausea, hallucinations, and insomnia.^[Ref]

Nervous system

• Very common (10% or more): Dyskinesia (up to 17%)
• Common (1% to 10%): Dizziness

Across clinical trials, dyskinesia occurred in 15% of patients receiving 20 mg once a day and 17% of patients receiving 40 mg once a day (compared to 8% for placebo); 1% of patients discontinued treatment because of dyskinesia.

Gastrointestinal

• Common (1% to 10%): Constipation, nausea

Dermatologic

• Common (1% to 10%): Rash

Metabolic

• Common (1% to 10%): Decreased appetite, increased blood glucose

Hepatic

• Common (1% to 10%): Blood alkaline phosphatase increased

Respiratory

• Common (1% to 10%): Upper respiratory tract inflammation

Renal

• Common (1% to 10%): Blood urea increased

Psychiatric

• Common (1% to 10%): Hallucinations, abnormal thinking and behavior, insomnia
• Rare (less than 0.1%): Impulse control disorder
• Postmarketing reports: Increased libido

Across clinical trials, hallucinations occurred in 2% of patients receiving 20 mg once a day and 6% of patients receiving 40 mg once a day (compared to 3% for placebo); 1% of patients discontinued treatment because of hallucinations. Across clinical trials, abnormal thinking and behavior (paranoid ideation, delusions, confusion, mania, disorientation, aggressive behavior, agitation, or delirium) occurred in 1% of patients receiving 20 mg once a day and 2% of patients receiving 40 mg once a day (compared to 1% for placebo). Across clinical trials, 1 patient taking 40 mg/day reported an impulse control disorder. There were no reports in the patients taking 20 mg/day or placebo.

Further information

Istradefylline side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer