Version July 2025
Serdexmethylphenidate/dexmethylphenidate has a high potential for abuse and misuse, which can lead to the development of a substance use disorder, including addiction. Misuse and abuse of CNS stimulants, including serdexmethylphenidate/dexmethylphenidate, can result in overdose and death, and this risk is increased with higher doses or unapproved methods of administration, such as snorting or injection.
Before prescribing serdexmethylphenidate/dexmethylphenidate, assess each patient’s risk for abuse, misuse, and addiction. Educate patients and their families about these risks, proper storage of the drug, and proper disposal of any unused drug. Throughout serdexmethylphenidate/dexmethylphenidate treatment, reassess each patient’s risk of abuse, misuse, and addiction and frequently monitor for signs and symptoms of abuse, misuse, and addiction.
Attention-deficit/hyperactivity disorder (ADHD):
Note: Serdexmethylphenidate/dexmethylphenidate (Azstarys) has a different pharmacokinetic profile and base composition of methylphenidate and should not be substituted for any other methylphenidate products on a mg:mg basis. Azstarys is a fixed-dose combination product, titration increments based on available capsule strengths. Discontinue medication if no improvement is seen after appropriate dosage adjustment over a 1-month period of time.
Children ≥6 years: Azstarys: Oral: Initial: Serdexmethylphenidate 39.2 mg/dexmethylphenidate 7.8 mg capsule once daily in the morning; after 1 week, may titrate dose based on response and tolerability to a higher dose of serdexmethylphenidate 52.3 mg/dexmethylphenidate 10.4 mg capsule once daily or if necessary, decrease dose to serdexmethylphenidate 26.1 mg/dexmethylphenidate 5.2 mg capsule once daily. Discontinuation may be necessary for paradoxical aggravation of symptoms or other adverse reactions; maximum daily dose: serdexmethylphenidate 52.3 mg/dexmethylphenidate 10.4 mg per day.
Adolescents: Azstarys: Oral: Initial: Serdexmethylphenidate 39.2 mg/dexmethylphenidate 7.8 mg capsule once daily in the morning for 1 week then increase to serdexmethylphenidate 52.3 mg/dexmethylphenidate 10.4 mg capsule once daily; maximum daily dose: serdexmethylphenidate 52.3 mg/dexmethylphenidate 10.4 mg per day. A dose reduction or discontinuation may be needed for paradoxical aggravation of symptoms or other adverse reactions.
Converting from other methylphenidate products to Azstarys: Discontinue other methylphenidate product and begin Azstarys according to initial and titration dosing shown above.
Children ≥6 years and Adolescents: There are no dosage adjustments provided in manufacturer's labeling (has not been studied); however, dosage adjustment unlikely because renal elimination is not an important factor in the clearance of serdexmethylphenidate or dexmethylphenidate.
Children ≥6 years and Adolescents: There are no dosage adjustments provided in manufacturer's labeling (has not been studied).
(For additional information see "Serdexmethylphenidate and dexmethylphenidate: Drug information")
Attention-deficit/hyperactivity disorder: Oral: Initial: Serdexmethylphenidate 39.2 mg/dexmethylphenidate 7.8 mg once daily in the morning; after 1 week, may increase dose to serdexmethylphenidate 52.3 mg/ dexmethylphenidate 10.4 mg once daily; maximum dose: serdexmethylphenidate 52.3 mg/ dexmethylphenidate 10.4 mg once daily. A dose reduction or discontinuation may be needed for paradoxical aggravation of symptoms or other adverse reactions.
Converting from other methylphenidate products to serdexmethylphenidate/dexmethylphenidate: Discontinue other methylphenidate product and begin serdexmethylphenidate/dexmethylphenidate according to initial and titration dosing; do not substitute on a mg-per-mg basis.
There are no dosage adjustments provided in the manufacturer's labeling (has not been studied); however, since little unchanged drug is eliminated in the urine, dosage adjustment in renal impairment is not required.
There are no dosage adjustments provided in the manufacturer's labeling.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. See Dexmethylphenidate monograph. Also refer to Methylphenidate for adverse effects seen with other methylphenidate products.
Frequency not defined:
Endocrine & metabolic: Weight loss
Nervous system: Drug abuse, drug dependence
Neuromuscular & skeletal: Linear skeletal growth rate below expectation
Postmarketing: Cardiovascular: Peripheral vascular disease, Raynaud's disease
Hypersensitivity (eg, bronchospasm, rash, pruritus) to serdexmethylphenidate, dexmethylphenidate, methylphenidate, or any component of the formulation; concomitant use with or within 14 days of monoamine oxidase inhibitors.
Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Concerns related to adverse effects:
• Cardiovascular events: CNS stimulant treatment has been associated with sudden death in patients with preexisting structural cardiac abnormalities or other serious cardiac disease. Consistent with other studies, a large retrospective cohort study involving 1,200,438 children, adolescents, and young adults (2 to 24 years of age) prescribed methylphenidate, dexmethylphenidate, dextroamphetamines, amphetamine salts, pemoline, or atomoxetine found no evidence that current use of an ADHD medication increased risk for sudden cardiac death, acute MI, or stroke (Cooper 2011).
• Hypersensitivity: Hypersensitivity reactions, including angioedema and anaphylactic reactions, have been reported in patients treated with methylphenidate-containing products.
• Hypertension/tachycardia: May occur; monitor blood pressure and heart rate in all patients.
• Peripheral vasculopathy: Stimulants are associated with peripheral vasculopathy, including Raynaud phenomenon; signs and symptoms are usually intermittent and mild, and generally improve with dose reduction and discontinuation. Peripheral vasculopathy effects have been observed at different times, at therapeutic doses, and in all age groups. Digital ulceration and/or soft tissue breakdown have been observed rarely; monitor for digital changes during therapy and seek further evaluation (eg, rheumatology) if necessary.
• Priapism: Prolonged and painful erections, sometimes requiring surgical intervention, have been reported with use of methylphenidate-containing products, in both pediatric and adult patients. Priapism has been reported to develop after some time on the drug, often subsequent to an increase in dose but also during a period of drug withdrawal (drug holidays or discontinuation). Patients with certain hematological dyscrasias (eg, sickle cell disease), malignancies, perineal trauma, or concomitant use of alcohol, illicit drugs, or other medications associated with priapism may be at increased risk (Eiland 2014). Patients who develop abnormally sustained or frequent and painful erections should discontinue therapy and seek immediate medical attention. An emergent urological consultation should be obtained in severe cases. In patients with severe cases of priapism that were slow to resolve and/or required detumescence by aspiration, avoidance of stimulants and atomoxetine may be preferred (Eiland 2014).
Disease-related concerns:
• Cardiovascular disorders: Avoid use in patients with known structural cardiac abnormalities, cardiomyopathy, serious cardiac arrhythmia, coronary artery disease, or other serious cardiac disease.
• Psychiatric disorders: Use with caution in patients with preexisting psychosis (may exacerbate symptoms of behavior and thought disorder) or bipolar disorder (may induce mixed/manic episode). New-onset psychosis or mania may occur with stimulant use. Patients should be screened for bipolar disorder and risk factors for developing a manic episode prior to treatment (eg, comorbid or history of depressive symptoms; family history of suicide, bipolar disorder, or depression); consider discontinuation if psychotic or manic symptoms (eg, delusional thinking, hallucinations, mania) occur.
• Seizure disorder: Limited information exists regarding stimulant use in seizure disorder. Whereas patients with attention-deficit hyperactivity disorder are at an increased risk for seizure activity compared to the general population, a retrospective study using drug claims data showed that the use of stimulant medications was associated with a lower risk (Cortese 2013; Wiggs 2018). Manufacturers of some stimulants recommend discontinuing therapy if seizures occur.
• Tourette syndrome/tics: Use with caution in patients with Tourette syndrome or other tic disorders. Stimulants may exacerbate tics (motor and phonic) and Tourette syndrome; however, evidence demonstrating increased tics is limited. Evaluate for tics and Tourette syndrome prior to therapy initiation (AACAP [Murphy 2013]; Pliszka 2007).
Special populations:
• Pediatric: Use of CNS stimulants has been associated with appetite suppression, weight loss, and slowing of growth rate; monitor growth rate, height, and weight during treatment. A long-term (12-month) study reported lower than expected increases in height and weight in patients 6 to 12 years of age on serdexmethylphenidate and dexmethylphenidate; treatment interruption may be necessary in patients who are not increasing in height or gaining weight as expected.
Other warnings/precautions:
• Discontinuation of therapy: Abrupt discontinuation, rapid dose reduction, or administration of an antagonist may result in withdrawal symptoms, including dysphoric mood, fatigue, vivid, unpleasant dreams, insomnia or hypersomnia, increased appetite, and psychomotor retardation or agitation.
CNS stimulant treatment has been associated with sudden death in children and adolescents with preexisting structural cardiac abnormalities; one study reported methylphenidate increased risk for arrhythmia and myocardial infarction (MI) in youth without congenital heart disease (Shin 2016) and a retrospective case-control study reported an association with stimulants and sudden unexplained death in youth (Gould 2009). However, as noted in reviews (Martinez-Raga 2013; Westover 2012) several large studies have not found an association between prescription stimulants and cardiovascular events; though most retrospective studies were large (n=55,383 to 2,131,953), some had statistical power or methodological limitations (Westover 2012). A large retrospective cohort study involving 1,200,438 children and young adults (aged 2 to 24 years) prescribed attention-deficit hyperactivity disorder (ADHD) medication (methylphenidate, dexmethylphenidate, dextroamphetamines, amphetamine salts, pemoline, or atomoxetine) found no evidence that ADHD medication was associated with an increased risk of serious cardiovascular events (ie, acute MI, sudden cardiac death, stroke) in current (adjusted hazard ratio: 0.75; 95% CI: 0.31 to 1.85) or former (adjusted hazard ratio: 1.03; 95% CI: 0.57 to 1.89) users compared with nonusers, nor in current compared with former users. Results were similar with multiple alternative analyses to assess for bias or study assumptions. While point estimates of relative risks for ADHD drugs did not demonstrate increased risk, the upper limit of the 95% CI suggested a doubling of the risk could not be ruled out, although absolute magnitude of increased risk would be low. Data on any individual medication, other than methylphenidate, were too sparse for separate regression analyses (Cooper 2011). Prior to treatment with medications for ADHD, the American Heart Association and the American Academy of Pediatrics recommend that all children and adolescents diagnosed with ADHD have a thorough cardiovascular assessment, including patient and family health histories, determination of all medications used (prescribed and over-the-counter), and a physical examination focused on cardiovascular disease risk factors. An ECG is not mandatory but is reasonable to consider prior to stimulant medication therapy. Prompt evaluation and appropriate referral and testing, if warranted, should occur if any cardiac symptoms present (Vetter 2008).
Evaluation of the effect of stimulants on growth in ADHD diagnosed children <12 years receiving treatment for at least 3 years with stimulants has shown decreased height and weight changes over time compared to age matched control; height: 4.7 to 5.5 cm/year compared to 6.3 cm/year and 2.1 to 3.3 kg/year compared to 4.4 kg/year (Poulton 2016). In 5,315 pediatric patients (age range: 8 to 17 years) actively treated with stimulants (methylphenidate, dexmethylphenidate, dextroamphetamine, atomoxetine, lisdexamfetamine), significant reductions in total femoral, femoral neck, and lumbar bone mineral density (BMD) were observed compared to matched unmedicated controls (n=1,967); also reported were significantly more subjects in the stimulant-treated group with BMD measurements in the osteopenic range compared to matched controls (38.3% to 21.6%); of note, there was no data on duration of medication treatment, dosing, or therapy changes (Howard 2017). A longitudinal cohort-controlled trial reported no difference in peak height velocity and final adult height in subjects with ADHD and/or treated with stimulants (Harstad 2014).
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, Oral:
Azstarys: Serdexmethylphenidate 26.1 mg and dexmethylphenidate 5.2 mg [contains fd&c blue #1 (brilliant blue)]
Azstarys: Serdexmethylphenidate 39.2 mg and dexmethylphenidate 7.8 mg [contains fd&c blue #1 (brilliant blue), fd&c red #40 (allura red ac dye)]
Azstarys: Serdexmethylphenidate 52.3 mg and dexmethylphenidate 10.4 mg [contains fd&c red #40 (allura red ac dye), fd&c yellow #6 (sunset yellow)]
No
Capsules (Azstarys Oral)
26.1-5.2 mg (per each): $17.41
39.2-7.8 mg (per each): $17.41
52.3-10.4 mg (per each): $17.41
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Treatment with serdexmethylphenidate/dexmethylphenidate should include "drug holidays" or periodic discontinuation in order to assess the patient's requirements, decrease tolerance, and limit suppression of linear growth and weight. Medications used to treat attention-deficit hyperactivity disorder should be part of a total treatment program that may include other components such as psychological, educational, and social measures. Azstarys is fixed molar combination of 30% dexmethylphenidate (active drug, d-enantiomer of methylphenidate) and 70% serdexmethylphenidate (prodrug of dexmethylphenidate).
C-II
Oral: Capsule: Administer in the morning without regard to food. May swallow capsule whole, or sprinkle contents in applesauce or water.
Oral administration in water or food: Open capsule and sprinkle contents into 50 mL of water or over 2 tablespoons of applesauce; consume within 10 minutes; do not store for future use.
Oral: Administer in the morning without regard to food. Capsules may be opened, and the contents sprinkled onto 50 mL of water or 2 tablespoons of applesauce. The prepared mixture should be administered immediately after or within 10 minutes of mixing; do not store for future use.
Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C to 30°C (59°F to 86°F). Protect from moisture. Dispense in tight container.
An FDA-approved patient medication guide, which is available with the product information and as follows, must be dispensed with this medication:
Azstarys: https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/212994s000lbl.pdf#page=26
Treatment of attention-deficit hyperactivity disorder (ADHD) (Azstarys: FDA approved in ages ≥6 years and adults).
Serdexmethylphenidate/dexmethylphenidate may be confused with methylphenidate, dexmethylphenidate.
Azstarys may be confused with Astatin brand name for atorvastatin [multiple international markets].
Refer to individual components.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program
Acebrophylline: May increase stimulatory effects of CNS Stimulants. Risk X: Avoid
Amifampridine: Agents With Seizure Threshold Lowering Potential may increase neuroexcitatory and/or seizure-potentiating effects of Amifampridine. Risk C: Monitor
Antihypertensive Agents: Dexmethylphenidate may decrease therapeutic effects of Antihypertensive Agents. Risk C: Monitor
Antipsychotic Agents: May increase adverse/toxic effects of Dexmethylphenidate-Methylphenidate. Dexmethylphenidate-Methylphenidate may increase adverse/toxic effects of Antipsychotic Agents. Specifically, the risk of extrapyramidal symptoms may be increased when these agents are combined. Risk C: Monitor
Atomoxetine: May increase hypertensive effects of Sympathomimetics. Atomoxetine may increase tachycardic effects of Sympathomimetics. Risk C: Monitor
Bornaprine: Sympathomimetics may increase anticholinergic effects of Bornaprine. Risk C: Monitor
BuPROPion: May increase neuroexcitatory and/or seizure-potentiating effects of Agents With Seizure Threshold Lowering Potential. Risk C: Monitor
Cannabinoid-Containing Products: May increase tachycardic effects of Sympathomimetics. Risk C: Monitor
Cocaine (Topical): May increase hypertensive effects of Sympathomimetics. Management: Consider alternatives to use of this combination when possible. Monitor closely for substantially increased blood pressure or heart rate and for any evidence of myocardial ischemia with concurrent use. Risk D: Consider Therapy Modification
Dihydralazine: Sympathomimetics may decrease therapeutic effects of Dihydralazine. Risk C: Monitor
Doxofylline: Sympathomimetics may increase adverse/toxic effects of Doxofylline. Risk C: Monitor
Esketamine (Injection): May increase adverse/toxic effects of Sympathomimetics. Specifically, the risk for elevated heart rate, hypertension, and arrhythmias may be increased. Risk C: Monitor
Esketamine (Nasal): May increase hypertensive effects of CNS Stimulants. Risk C: Monitor
Fluorodopa F18: Coadministration of CNS Stimulants and Fluorodopa F18 may alter diagnostic results. Management: Discontinue medications used to treat Parkinson disease, including dopamine reuptake inhibitors and dopamine releasing agents, such as psychostimulants, 12 hours prior to fluorodopa F 18 administration if these medications can be safely withheld. Risk D: Consider Therapy Modification
Guanethidine: May increase hypertensive effects of Sympathomimetics. Guanethidine may increase arrhythmogenic effects of Sympathomimetics. Risk C: Monitor
Inhalational Anesthetics: Dexmethylphenidate-Methylphenidate may increase hypertensive effects of Inhalational Anesthetics. Management: Avoid the use of dexmethylphenidate/methylphenidate on the day of a planned surgery with an inhalational anesthetic. Risk D: Consider Therapy Modification
Iobenguane Radiopharmaceutical Products: CNS Stimulants may decrease therapeutic effects of Iobenguane Radiopharmaceutical Products. Management: Discontinue all drugs that may inhibit or interfere with catecholamine transport or uptake for at least 5 biological half-lives before iobenguane administration. Do not administer these drugs until at least 7 days after each iobenguane dose. Risk X: Avoid
Ioflupane I 123: Coadministration of Dexmethylphenidate and Ioflupane I 123 may alter diagnostic results. Risk C: Monitor
Iohexol: Agents With Seizure Threshold Lowering Potential may increase adverse/toxic effects of Iohexol. Specifically, the risk for seizures may be increased. Management: Discontinue agents that may lower the seizure threshold 48 hours prior to intrathecal use of iohexol. Wait at least 24 hours after the procedure to resume such agents. In nonelective procedures, consider use of prophylactic antiseizure drugs. Risk D: Consider Therapy Modification
Iomeprol: Agents With Seizure Threshold Lowering Potential may increase adverse/toxic effects of Iomeprol. Specifically, the risk for seizures may be increased. Management: Discontinue agents that may lower the seizure threshold 48 hours prior to intrathecal use of iomeprol. Wait at least 24 hours after the procedure to resume such agents. In nonelective procedures, consider use of prophylactic antiseizure drugs. Risk D: Consider Therapy Modification
Iopamidol: Agents With Seizure Threshold Lowering Potential may increase adverse/toxic effects of Iopamidol. Specifically, the risk for seizures may be increased. Management: Discontinue agents that may lower the seizure threshold 48 hours prior to intrathecal use of iopamidol. Wait at least 24 hours after the procedure to resume such agents. In nonelective procedures, consider use of prophylactic antiseizure drugs. Risk D: Consider Therapy Modification
Kratom: May increase adverse/toxic effects of Sympathomimetics. Risk X: Avoid
Landiolol: Sympathomimetics may decrease therapeutic effects of Landiolol. Risk C: Monitor
Levothyroxine: May increase therapeutic effects of Sympathomimetics. Sympathomimetics may increase therapeutic effects of Levothyroxine. Levothyroxine may increase adverse/toxic effects of Sympathomimetics. Specifically, the risk of coronary insufficiency may be increased in patients with coronary artery disease. Risk C: Monitor
Monoamine Oxidase Inhibitors: May increase hypertensive effects of Dexmethylphenidate. Risk X: Avoid
PHENobarbital: Dexmethylphenidate may increase serum concentration of PHENobarbital. Risk C: Monitor
Polyethylene Glycol-Electrolyte Solution: Agents With Seizure Threshold Lowering Potential may increase adverse/toxic effects of Polyethylene Glycol-Electrolyte Solution. Specifically, the risk of seizure may be increased. Risk C: Monitor
Primidone: Dexmethylphenidate may increase serum concentration of Primidone. Dexmethylphenidate may increase active metabolite exposure of Primidone. Specifically, phenobarbital concentrations could become elevated. Risk C: Monitor
Serotonergic Agents (High Risk): Dexmethylphenidate-Methylphenidate may increase serotonergic effects of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Risk C: Monitor
Sodium Phosphates: Agents With Seizure Threshold Lowering Potential may increase adverse/toxic effects of Sodium Phosphates. Specifically, the risk of seizure or loss of consciousness may be increased in patients with significant sodium phosphate-induced fluid or electrolyte abnormalities. Risk C: Monitor
Solriamfetol: CNS Stimulants may increase hypertensive effects of Solriamfetol. CNS Stimulants may increase tachycardic effects of Solriamfetol. Risk C: Monitor
Solriamfetol: Sympathomimetics may increase hypertensive effects of Solriamfetol. Sympathomimetics may increase tachycardic effects of Solriamfetol. Risk C: Monitor
Sympathomimetics: May increase adverse/toxic effects of Sympathomimetics. Risk C: Monitor
Tedizolid: May increase adverse/toxic effects of Sympathomimetics. Specifically, the risk for increased blood pressure and heart rate may be increased. Risk C: Monitor
Food may delay time to peak drug levels. Management: Administer without regard to meals.
Serdexmethylphenidate is a prodrug of dexmethylphenidate; dexmethylphenidate is the d-threo enantiomer of racemic methylphenidate; refer to the methylphenidate monograph for additional information.
Data collection to monitor pregnancy and infant outcomes following exposure to attention-deficit hyperactivity disorder medications is ongoing. Health care providers are encouraged to enroll patients exposed to serdexmethylphenidate/dexmethylphenidate during pregnancy in the National Pregnancy Registry for Psychostimulants (1-866-961-2388).
Prior to initiation of therapy, assess medical history and family history of sudden death or ventricular arrhythmia, and physical exam to assess for cardiac disease; patients should receive further evaluation if findings suggest cardiac disease, such as ECG and echocardiogram; promptly conduct cardiac evaluation in patients who develop exertional chest pain, unexplained syncope, or any other symptom of cardiac disease during treatment. For children already taking a stimulant, it is reasonable to evaluate medical and family history, review physical examination, and order ECG if not done prior to initiation (Vetter 2008).
Monitor growth (weight and height in children; baseline and periodically during therapy); blood pressure and heart rate (baseline, following dose increases, and periodically during treatment); appetite and sleep patterns; assess for motor or verbal tics or Tourette syndrome at baseline; observe for abnormal movements. Patients should be reevaluated at appropriate intervals to assess continued need of the medication. Observe for signs/symptoms of new or worsening aggression or hostility, depression, delusional thinking, hallucinations, or mania. Monitor for visual disturbances. Observe for digital changes suggestive of peripheral vasculopathy (eg, Raynaud phenomenon). Monitor for signs of misuse, abuse, substance use disorder, and diversion.
The exact mechanism of action of serdexmethylphenidate/dexmethylphenidate in attention-deficit hyperactivity disorder is unknown. Serdexmethylphenidate is a prodrug of dexmethylphenidate. Dexmethylphenidate is the more active, d-threo-enantiomer, of racemic methylphenidate. It is a CNS stimulant that blocks the reuptake of norepinephrine and dopamine, and increases their release into the extraneuronal space. Studies (in vitro) with serdexmethylphenidate demonstrated little or no affinity to monoaminergic reuptake transporters.
Distribution: Vd: Serdexmethylphenidate: 29.3 L/kg.
Protein binding: Serdexmethylphenidate: ~56%; dexmethylphenidate ~47%.
Metabolism: Serdexmethylphenidate is likely converted to dexmethylphenidate mainly in the lower GI tract; dexmethylphenidate is metabolized via de-esterification to inactive metabolite d-α-phenyl-piperidine acetate (d-ritalinic acid).
Bioavailability: Serdexmethylphenidate: <3%.
Half-life elimination: Serdexmethylphenidate: 5.7 hours; dexmethylphenidate: 11.7 hours.
Time to peak: Dexmethylphenidate: ~2 hours; may be delayed to 4 to 4.5 hours with food.
Excretion: Serdexmethylphenidate: Urine: ~62% (~0.4% as unchanged drug); feces: ~37% (~11% as unchanged drug).
