NOURIANZ

Clinical safety rating: caution

Comprehensive clinical and safety monograph for NOURIANZ (NOURIANZ).

How it works

Nouri anze (istradefylline) is a selective adenosine A2A receptor antagonist. It modulates the activity of the basal ganglia by blocking A2A receptors, which are highly expressed in the striatum, thereby enhancing dopaminergic function and reducing motor symptoms associated with Parkinson's disease.

What the body does with it

Metabolism	Primarily metabolized by CYP1A1 and CYP3A4, with minor contributions from CYP2C8 and CYP2C9. N-dealkylation and O-demethylation are major pathways.
Excretion	Primarily hepatic metabolism via CYP3A4, with minimal renal excretion. Approximately 58% of the dose is excreted in feces (as unchanged drug and metabolites) and 1% in urine as unchanged istradefylline.
Half-life	Terminal elimination half-life is approximately 23 hours in healthy subjects; in patients with Parkinson's disease, the half-life may be prolonged (up to 29 hours) due to decreased clearance. This supports once-daily dosing.
Protein binding	Approximately 96% bound to plasma proteins, primarily albumin and α1-acid glycoprotein.
Volume of Distribution	Volume of distribution is approximately 2.3 L/kg, indicating extensive extravascular distribution. This large Vd reflects penetration into tissues, including the brain, consistent with its central mechanism of action.
Bioavailability	Absolute oral bioavailability is approximately 60%, but food increases exposure; taking with food (especially high-fat meals) increases AUC by about 2-fold and Cmax by 1.6-fold.
Onset of Action	Oral administration: Clinical effects on motor fluctuations (reduction in OFF time) are typically observed within 1–2 weeks of initiating therapy, with maximal benefit often seen by 4 weeks.
Duration of Action	Once-daily dosing provides sustained reduction in OFF time over a 24-hour period. The duration of action is consistent with its long half-life, allowing continuous adenosine A2A receptor blockade.

Classification & Brands

Dosing & administration

20 mg orally three times daily (approximately 6 hours apart) for adults.

Dosage form	TABLET
Renal impairment	No dose adjustment recommended for mild to moderate renal impairment (eGFR 30-89 mL/min). Not recommended for severe renal impairment (eGFR <30 mL/min) or end-stage renal disease (ESRD) as no data available.
Liver impairment	No dose adjustment for mild hepatic impairment (Child-Pugh A). Not recommended for moderate to severe hepatic impairment (Child-Pugh B or C) due to lack of data.
Pediatric use	Safety and efficacy in pediatric patients (<18 years) have not been established; no recommended dosing.
Geriatric use	No specific dose adjustment required based on age alone, but monitor renal function due to age-related decline; dose adjustment for renal impairment as per adult guidelines.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for NOURIANZ (NOURIANZ).

Breastfeeding	No data on presence in human milk, effects on breastfed infant, or milk production. M/P ratio unknown. Caution advised; consider developmental and health benefits of breastfeeding alongside mother's clinical need.
Teratogenic Risk	Animal studies show no evidence of teratogenicity at clinically relevant exposures. Human data are insufficient to establish risk; use only if potential benefit justifies potential risk to fetus. Risks across trimesters are unknown due to lack of adequate human studies.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

["History of hypersensitivity to istradefylline or any component of the formulation.","Concurrent use of strong CYP1A1 inducers (e.g., rifampin, smoking) due to potential for reduced efficacy."]

Clinical Precautions

Precautions

["May cause dyskinesia or exacerbate existing dyskinesia; monitor and consider levodopa dose reduction.","May cause hallucinations or psychotic-like behavior; use with caution in patients with pre-existing psychiatric disorders.","May cause orthostatic hypotension; monitor blood pressure, especially during dose titration.","May impair ability to drive or operate machinery; advise caution until effect is known.","Risk of impulse control disorders (e.g., pathological gambling, hypersexuality); monitor and consider dose reduction if symptoms develop.","Not recommended in patients with severe hepatic impairment (Child-Pugh class C)."]

Clinical Tips & Counseling

Drug interactions

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NOURIANZ

Clinical safety rating: caution

Comprehensive clinical and safety monograph for NOURIANZ (NOURIANZ).

How it works

What the body does with it

Metabolism	Primarily metabolized by CYP1A1 and CYP3A4, with minor contributions from CYP2C8 and CYP2C9. N-dealkylation and O-demethylation are major pathways.
Excretion	Primarily hepatic metabolism via CYP3A4, with minimal renal excretion. Approximately 58% of the dose is excreted in feces (as unchanged drug and metabolites) and 1% in urine as unchanged istradefylline.
Half-life	Terminal elimination half-life is approximately 23 hours in healthy subjects; in patients with Parkinson's disease, the half-life may be prolonged (up to 29 hours) due to decreased clearance. This supports once-daily dosing.
Protein binding	Approximately 96% bound to plasma proteins, primarily albumin and α1-acid glycoprotein.
Volume of Distribution	Volume of distribution is approximately 2.3 L/kg, indicating extensive extravascular distribution. This large Vd reflects penetration into tissues, including the brain, consistent with its central mechanism of action.
Bioavailability	Absolute oral bioavailability is approximately 60%, but food increases exposure; taking with food (especially high-fat meals) increases AUC by about 2-fold and Cmax by 1.6-fold.
Onset of Action	Oral administration: Clinical effects on motor fluctuations (reduction in OFF time) are typically observed within 1–2 weeks of initiating therapy, with maximal benefit often seen by 4 weeks.
Duration of Action	Once-daily dosing provides sustained reduction in OFF time over a 24-hour period. The duration of action is consistent with its long half-life, allowing continuous adenosine A2A receptor blockade.

Classification & Brands

Dosing & administration

20 mg orally three times daily (approximately 6 hours apart) for adults.

Dosage form	TABLET
Renal impairment	No dose adjustment recommended for mild to moderate renal impairment (eGFR 30-89 mL/min). Not recommended for severe renal impairment (eGFR <30 mL/min) or end-stage renal disease (ESRD) as no data available.
Liver impairment	No dose adjustment for mild hepatic impairment (Child-Pugh A). Not recommended for moderate to severe hepatic impairment (Child-Pugh B or C) due to lack of data.
Pediatric use	Safety and efficacy in pediatric patients (<18 years) have not been established; no recommended dosing.
Geriatric use	No specific dose adjustment required based on age alone, but monitor renal function due to age-related decline; dose adjustment for renal impairment as per adult guidelines.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for NOURIANZ (NOURIANZ).

Breastfeeding	No data on presence in human milk, effects on breastfed infant, or milk production. M/P ratio unknown. Caution advised; consider developmental and health benefits of breastfeeding alongside mother's clinical need.
Teratogenic Risk	Animal studies show no evidence of teratogenicity at clinically relevant exposures. Human data are insufficient to establish risk; use only if potential benefit justifies potential risk to fetus. Risks across trimesters are unknown due to lack of adequate human studies.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

None

Side Effect Profile

Serious Effects

Absolute Contraindications

["History of hypersensitivity to istradefylline or any component of the formulation.","Concurrent use of strong CYP1A1 inducers (e.g., rifampin, smoking) due to potential for reduced efficacy."]