Names and pronunciation
(iz-tra′de-fye′leen) Nourianz
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Drug reference
(iz-tra′de-fye′leen) Nourianz
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Func. class.: Anti-Parkinson agent
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Chem. class.: Adenosine receptor antagonist I
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ACTION: Adenosine A2A receptor antagonist that acts through a nondopa- minergic mechanism to improve motor function
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USES: Adjuvant treatment in patients with Parkinson’s disease experiencing “off” episodes
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CONTRAINDICATIONS Hypersensitivity Precautions: Behavioral changes, breastfeeding, children, contraception requirements, dyskinesia, ge- riatric, hepatic disease, impulse control symptoms, infants, pregnancy, psychosis, re- productive risk, tobacco smoking
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SIDE EFFECTS CNS: Dyskinesia, psychosis, dizziness, hallucinations, insomnia GI: Nausea, constipation
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INTERACTIONS Increased: istradefylline effect—strong CYP3A4 inhibitors (ketoconazole, itracon- azole, clarithromycin); max 20 mg daily Decreased: istradefylline effect—strong CYP3A4 inducers (carBAMazepine, rifAMPin, phenytoin, St. John’s wort); avoid using together Drug: herb Decreased: istradefylline effect—St. John’s wort; avoid using together
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DOSAGE AND ROUTES Adults PO 20 mg daily; adjust dose based on response and tolerability; max: 40 mg daily; 20 or more ciga- rettes, 40 mg daily
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Available forms: Tabs 20, 40 mg
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Administer: May give without regard to meals
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Assess: • Parkinson’s disease: Assess for decreas ing “off” episodes, tremors usually first appearing in hands/foot while at rest, slow movement, rigidity, postural instability, problems with speech and voice, inconti- nence, difficulty swallowing, inability to start movements or continue repeated movement, excessive sweating, constipa- tion, dry skin, mood changes • Dyskinesia: Assess for grimacing, eye blinking, lip smacking, repetitive move- ments, these should lessen with treatment • Hallucinations/psychosis/impulse control/compulsive behaviors: Assess for these effects, and if present, decreased dose or discontinuation of treatment may be needed • Monitor LFTs in hepatic disease
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Evaluate: • Therapeutic response: decreasing symptoms of Parkinson’s disease
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CLINICAL CONSIDERATIONS
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Patient and caregiver information: • To identify if tobacco is used and, if so, how much per day; dosage change may be needed • To identify all Rx, OTC, herbals, sup- plements that are used and discuss with health care provider • Pregnancy/breastfeeding: Identify if pregnancy is planned or suspected or if breastfeeding, use in pregnancy is not recommended; adequate contraception should be used in women of childbearing age
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PHARMACOKINETICS • Protein binding 98%, metabolized by CYP1A1, CYP3A4, with a minor contribution from CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C18, and CYP2D6 metabolites 39% and excreted urine (39%), feces (48%); half-life 83 hr; dosage modifications are needed in heavy smoking; peak 4 hr (fast- ing), increased with high-fat meal
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