Istradefylline

Istradefylline is indicated as adjunctive treatment to levodopa/carbidopa in adult patients with Parkinson's disease (PD) experiencing "off" episodes.

Istradefylline is a selective adenosine A_2A receptor inhibitor. These receptors are found in the basal ganglia, a region of the brain that suffers degeneration in Parkinson's disease, and is also significantly involved in motor control. A_2A receptors are also expressed on GABAergic medium spiny neurons within the indirect striato-pallidal pathway. The GABAergic action of this pathway is thereby reduced. Istradefylline has 56 times the affinity for A_2A receptors than A₁ receptors.

Dosing Information: The recommended dosage of Istradefylline is 20 mg administered orally once daily. The dosage may be increased to a maximum of 40 mg once daily, based on individual need and tolerability. Initial dose titration is not required. Istradefylline can be taken with or without food.

Dosage Adjustment with Strong CYP 3A4 Inhibitors: The maximum recommended dosage of Istradefylline with concomitant use of strong CYP3A4 inhibitors is 20 mg once daily.

Dosing with Strong CYP 3A4 Inducers: Avoid use of Istradefylline with strong CYP3A4 inducers.

Dosage Adjustment in Patients with Hepatic Impairment: The maximum recommended dosage of Istradefylline in patients with moderate hepatic impairment (Child-Pugh B) is 20 mg once daily. Closely monitor patients with moderate hepatic impairment for adverse reactions when on Istradefylline treatment. Avoid use of Istradefylline in patients with severe hepatic impairment (Child-Pugh C).

Dosage Adjustment for Tobacco Smokers: The recommended dosage of Istradefylline in patients who use tobacco in amounts of 20 or more cigarettes per day (or the equivalent of another tobacco product) is 40 mg once daily

The following clinically significant adverse reactions are:

• Dyskinesia
• Hallucinations / Psychotic Behavior
• Impulse Control / Compulsive Behaviors

There are no adequate data on the developmental risk associated with the use of Istradefylline in pregnant women. There are no data on the presence of istradefylline in human milk, the effects of istradefylline on the breastfed infant, or the effects of istradefylline on milk production. Istradefylline was present in the milk of lactating rats at concentrations up to 10 times that in maternal plasma. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for Istradefylline, and any potential adverse effects on the breastfed infant from Istradefylline or from the underlying maternal condition

Dyskinesia: Monitor patients for dyskinesia or exacerbation of existing dyskinesia.
Hallucinations/Psychotic Behavior: Consider dosage reduction or stopping Istradefylline if occurs.
Impulse Control/Compulsive Behaviors: Consider dosage reduction or stopping Istradefylline if occurs

Pediatric Use: Safety and effectiveness in pediatric patients have not been established.

Geriatric Use: No adjustment of Istradefylline dosage is recommended on the basis of age. Of the total number of PD patients who received Istradefylline in clinical trials, 53% were ≥65 years and 13% were ≥75 years of age. No overall differences in effectiveness were observed between these patients and younger patients

Antiparkinson drugs

Keep below 30°C temperature, away from light & moisture. Keep out of the reach of children.