methylphenidate hydrochloride CD - Lannett Company, LLC

Prior to treating patients with Methylphenidate HCl Extended-Release Capsules CD, assess:

• The risk for abuse, misuse, and addiction [see Warnings and Precautions (5.1)].
• For the presence of cardiac disease (e.g., perform a careful history, family history of sudden death or ventricular arrhythmia, and physical exam) [see Warnings and Precautions (5.2)].
• The risk for developing a manic episode (e.g., history of depressive symptoms or a family history of suicide, bipolar disorder, or depression) [see Warnings and Precautions (5.4)].
• For a family history for tics or Tourette syndrome and clinically evaluate patients for motor or verbal tics or Tourette syndrome [see Warnings and Precautions (5.10)].

The recommended starting dosage of Methylphenidate HCl Extended-Release Capsules CD in pediatric patients 6 years of age and older is 20 mg once daily.  Dosage may be adjusted weekly in 10 mg to 20 mg increments to the maximum recommended dosage of 60 mg per day.

Take Methylphenidate HCl Extended-Release Capsules CD orally once daily in the morning, before breakfast [see Clinical Pharmacology ( 12.3 )].

Swallow the extended-release capsules whole with the aid of liquids. Alternatively, open the extended-release capsules and sprinkle the contents onto a small amount (tablespoon) of applesauce and administer immediately and then drink fluids.  Do not store for future use.  Do not crush or chew the extended-release capsules.

If paradoxical aggravation of ADAD symptoms or Methylphenidate HCl Extended-Release Capsules CD-associated adverse reactions occur, reduce dosage or, if necessary, discontinue Methylphenidate HCl Extended-Release Capsules CD. If ADHD improvement is not observed after appropriate dosage adjustment over a one-month period, discontinue Methylphenidate HCl Extended-Release Capsules CD.

Methylphenidate HCl Extended-Release Capsules CD has a high potential for abuse and misuse. The use of Methylphenidate HCl Extended-Release Capsules CD exposes individuals to the risks of abuse and misuse, which can lead to the development of a substance use disorder, including addiction. Misuse and abuse of CNS stimulants, including Methylphenidate HCl Extended-Release Capsules CD, can result in overdose and death [see Overdosage ( 10 )], and this risk is increased with a higher dosage or unapproved methods of administration, such as snorting or injection.

Before prescribing Methylphenidate HCl Extended-Release Capsules CD, assess each patient’s risk for abuse, misuse, and addiction. Educate patients and their families about these risks and proper disposal of any unused drug. Advise patients and/or their caregivers to store Methylphenidate HCl Extended-Release Capsules CD in a safe place, preferably locked, and instruct patients and/or their caregivers to not give Methylphenidate HCl Extended-Release Capsules CD to anyone else. Throughout Methylphenidate HCl Extended-Release Capsules CD treatment, reassess each patient’s risk of abuse, misuse, and addiction and frequently monitor for signs and symptoms of abuse, misuse, and addiction.

Sudden death has been reported in patients with structural cardiac abnormalities or other serious cardiac disease who were treated with CNS stimulants at the recommended dosage.

Prior to treating patients with Methylphenidate HCl Extended-Release Capsules CD, assess for the presence of cardiac disease (e.g., perform a careful history, family history of sudden death or ventricular arrhythmia, and physical exam). Avoid Methylphenidate HCl Extended-Release Capsules CD use in patients with known structural cardiac abnormalities, cardiomyopathy, serious cardiac arrhythmia, coronary artery disease, or other serious cardiac problems.

CNS stimulants cause an increase in blood pressure (mean increase approximately 2 to 4 mmHg) and heart rate (mean increase approximately 3 to 6 bpm). Some patients may have larger increases.

Monitor all Methylphenidate HCl Extended-Release Capsules CD treated patients for hypertension and tachycardia.

Exacerbation of Pre-Existing Psychosis in Patients with a Psychotic Disorder

CNS stimulants, including Methylphenidate HCl Extended-Release Capsules CD, may exacerbate symptoms of behavior disturbance and thought disorder in patients with a pre-existing psychotic disorder.

Induction of a Manic Episode in Patients with Bipolar Disorder

CNS stimulants, including Methylphenidate HCl Extended-Release Capsules CD, may induce a manic or mixed episode in patients with bipolar disorder. Prior to initiating Methylphenidate HCl Extended-Release Capsules CD treatment, screen patients for risk factors for developing a manic episode (e.g., comorbid or history of depressive symptoms or a family history of suicide, bipolar disorder, or depression).

New Psychotic or Manic Symptoms in Patients without a History of a Bipolar or Psychotic Disorder

CNS stimulants, including Methylphenidate HCl Extended-Release Capsules CD, at the recommended dosages, may cause psychotic or manic symptoms (e.g., hallucinations, delusional thinking, or mania) in patients without a prior history of psychotic illness or mania. In a pooled analysis of multiple short-term, placebo-controlled studies of CNS stimulants, psychotic or manic symptoms occurred in approximately 0.1% of CNC stimulant-treated patients, compared to 0% of placebo-treated patients. If such symptoms occur, consider discontinuing Methylphenidate HCl Extended-Release Capsules CD.

Prolonged and painful erections, sometimes requiring surgical intervention, have been reported with methylphenidate use in both adult and pediatric male patients. Although priapism was not reported with methylphenidate initiation, it developed after some time on methylphenidate, often subsequent to an increase in dosage. Priapism also occurred during methylphenidate withdrawal (drug holidays or during discontinuation).

Methylphenidate HCl Extended-Release Capsules CD-treated patients who develop abnormally sustained or frequent and painful erections should seek immediate medical attention.

CNS stimulants, including Methylphenidate HCl Extended-Release Capsules CD, used to treat ADHD are associated with peripheral vasculopathy, including Raynaud’s phenomenon. Signs and symptoms of these cases of peripheral vasculopathy were usually intermittent and mild; however, sequelae have included digital ulceration and/or soft tissue breakdown. Effects of peripheral vasculopathy, including Raynaud’s phenomenon, were observed in post-marketing reports and at the therapeutic dosages of CNS stimulants in all age groups throughout the course of treatment. Signs and symptoms generally improved after dosage reduction in or discontinuation of the CNS stimulant.

Carefully assess for digital changes during Methylphenidate HCl Extended-Release Capsules CD treatment. Further clinical evaluation (e.g., rheumatology referral) may be appropriate for Methylphenidate HCl Extended-Release Capsules CD-treated patients who develop signs of symptoms of peripheral vasculopathy.

CNS stimulants have been associated with weight loss and slowing of growth rate in pediatric patients.  Careful follow-up of weight and height in pediatric patients ages 7 to 10 years who were randomized to either methylphenidate or non-medication treatment groups over 14 months, as well as in naturalistic subgroups of newly methylphenidate-treated and non-medication treated pediatric patients over 36 months (to the ages of 10 to 13 years), suggests that pediatric patients who received methylphenidate treatment for 7 days per week throughout the year had a temporary slowing in growth rate (on average, a total of about 2 cm less growth in height and 2.7 kg less growth in weight over 3 years), without evidence of growth rebound during this development period.  Methylphenidate HCl Extended-Release Capsules CD is not approved for use and is not recommended in pediatric patients below 6 years of age because of a higher incidence of adverse reactions including weight loss [see Use in Specific Populations ( 8.4 )].

Closely monitor growth (weight and height) in Methylphenidate HCl Extended-Release Capsules CD-treated pediatric patients. Pediatric patients who are not growing or gaining height or weight as expected may need to have their Methylphenidate HCl Extended-Release Capsules CD treatment interrupted. 

There have been reports of angle closure glaucoma associated with methylphenidate treatment. Although the mechanism is not clear, Methylphenidate HCl Extended-Release Capsules CD-treated patients considered at risk for acute angle closure glaucoma (e.g., patients with significant hyperopia) should be evaluated by an ophthalmologist.

There have been reports of an elevation of intraocular pressure (IOP) associated with methylphenidate treatment [see Adverse Reactions ( 6.2 )].

Prescribe Methylphenidate HCl Extended-Release Capsules CD to patients with open-angle glaucoma or abnormally increased IOP only if the benefit of treatment is considered to outweigh the risk. Closely monitor Methylphenidate HCl Extended-Release Capsules CD-treated patients with a history of abnormally increased IOP or open angle glaucoma.

CNS stimulants, including methylphenidate, have been associated with the onset or exacerbation of motor and verbal tics. Worsening of Tourette syndrome has also been reported [see Adverse Reactions ( 6.2 )].

Before initiating Methylphenidate HCl Extended-Release Capsules CD, assess the family history for tics or Tourette syndrome and clinically evaluate patients for tics or Tourette syndrome. Regularly monitor Methylphenidate HCl Extended-Release Capsules CD-treated patients for the emergence or worsening of tics or Tourette syndrome, and discontinue Methylphenidate HCl Extended-Release Capsules CD if clinically appropriate.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. 

The safety database is based on three clinical studies of  Methylphenidate HCl Extended-Release Capsules CD (i.e., Studies 1, 2, and 3) that included 188 Methylphenidate HCl Extended-Release Capsules CD-treated pediatric patients 6 years of age and older with ADHD.  Pediatric patients received Methylphenidate HCl Extended-Release Capsules CD 20 mg, 40 mg, and/or 60 mg once daily:

• Study 1 was a 3-week placebo-controlled clinical study that included 314 pediatric patients (ages 6 to 15 years; Methylphenidate HCl Extended-Release Capsules CD n=155)
• Study 2 was a placebo-controlled, crossover clinical study that included 25 pediatric patients (ages 7 to 12 years); and
• Study 3 was an uncontrolled clinical study that included 8 pediatric patients (ages 6 to 10 years).

Adverse Reactions Leading to Discontinuation of Treatment

In Study 1, 1% (2/155) Methylphenidate HCl Extended-Release Capsules CD-treated patients and no placebo-treated patients discontinued due to an adverse reaction.  One Methylphenidate HCl Extended-Release Capsules CD-treated patient discontinued due to rash and pruritus; and the other Methylphenidate HCl Extended-Release Capsules CD-treated patient discontinued due headache, abdominal pain, and dizziness.

Most Common Adverse Reactions

The most common adverse reactions that occurred in 5% or more of Methylphenidate HCl Extended-Release Capsules CD-treated and at least twice as great in the Methylphenidate HCl Extended-Release Capsules CD-treated patients compared to the placebo-treated patients in a pool of Studies 1, 2 and 3 in pediatric patients 6 to 15 years of age were anorexia and insomnia.

Adverse reactions that occurred in ≥5% of Methylphenidate HCl Extended-Release Capsules CD-treated patients with a greater incidence in Methylphenidate HCl Extended-Release Capsules CD-treated patients than placebo-treated patients in pooled Studies, 1, 2, and 3 are presented in Table 2:

Table 2:  Adverse Reactions¹ in Pediatric Patients Ages 6 to 15 Years with ADHD in Pooled Three to Four Week Trials (Studies 1, 2, and 3)

¹ Adverse reactions that occurred in ≥5% of Methylphenidate HCl Extended-Release Capsules CD-treated patients with a greater incidence in Methylphenidate HCl Extended-Release Capsules CD-treated patients than placebo-treated patients

The following adverse reactions have been identified during postmarketing use of Methylphenidate HCl Extended-Release Capsules CD and other methylphenidate products.  Because these reactions are reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency or establish a causal relationship to drug exposure.  

Adverse Reactions with Methylphenidate HCl Extended-Release Capsules CD

• Blood and the lymphatic system disorders: thrombocytopenia
• Cardiac disorders: cardiac arrest, sudden death
• Immune system disorders: angioedema
• Musculoskeletal and connective tissue disorders: rhabdomyolysis
• Psychiatric disorders: abnormal behavior, aggression, anxiety, irritability, obsessive-compulsive disorder, suicidal behavior (including completed suicide), libido changes, serotonin syndrome in combination with serotonergic drugs
• Nervous System Disorder: migraine, reversible ischemic neurological deficit, bruxism
• Skin and subcutaneous tissue disorders: fixed drug eruption
• Vascular disorders: peripheral coldness, Raynaud’s phenomenon

Adverse Reactions with Other Methylphenidate Products

• Blood and the lymphatic system disorders: leukopenia, anemia, pancytopenia
• Cardiac disorders: palpitations; increased blood pressure, tachycardia, angina pectoris, cardiac arrhythmia, myocardial infarction, bradycardia, extrasystole
• Eye disorders: blurred vision, difficulties in visual accommodation, diplopia, increased intraocular pressure, mydriasis
• Gastrointestinal disorders: nausea, abdominal pain, dry mouth, vomiting, dyspepsia, diarrhea, constipation
• General Disorders: fatigue, hyperpyrexia
• Hepatobiliary disorders: abnormal liver function, ranging from transaminase elevation to severe hepatic injury
• Immune system disorders: hypersensitivity, including anaphylaxis, auricular swelling, bullous conditions, eruptions, exanthemas
• Infections and infestations: nasopharyngitis
• Metabolism and nutrition disorders: decreased appetite, reduced weight gain and suppression of growth during prolonged use in pediatric patients
• Musculoskeletal and connective tissue disorders: arthralgia, muscle cramps, myalgia, muscle twitching
• Nervous System Disorder: nervousness, dizziness, headache, dyskinesia, including choreoatheetoid movements, drowsiness, tremor, convulsions, cerebrovascular disorders (including vasculitis, cerebral hemorrhages and cerebrovascular accidents), serotonin syndrome in combination with serotonergic drugs, motor and verbal tics
• Psychiatric disorders: depressed mood, restlessness, agitation, psychosis (sometimes with visual and tactile hallucinations), affect liability, mania, disorientation
• Renal and urinary disorders: hematuria
• Reproductive system and breast disorders: gynecomastia
• Respiratory, thoracic and mediastinal disorders: pharyngolaryngeal pain, dyspnea, cough
• Skin and subcutaneous tissue disorders: scalp hair loss, hyperhidrosis, angioneurotic edema, erythema, exfoliative dermatitis, thrombocytopenic purpura, urticaria, erythema multiforme rash
• Urogenital disorders: priapism
• Vascular disorders: isolated cases of cerebral arteritis and/or occlusion

Pregnancy Exposure Registry

There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ADHD drugs, including Methylphenidate HCl Extended-Release Capsules CD, during pregnancy.  Healthcare providers are encouraged to advise patients to register by calling the National Pregnancy Registry for ADHD Medications at 1-866-961-2388 or visiting womensmentalhealth.org/adhd-medications.

Risk Summary
Published studies and postmarketing reports on methylphenidate use during pregnancy have inconsistent findings about a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. There are risks to the fetus associated with the use of central nervous system (CNS) stimulants during pregnancy (see Clinical Considerations).

No effects on morphological development were observed in embryo-fetal development studies with oral administration of methylphenidate to pregnant rats and rabbits during organogenesis at dosages up to 10 and 15 times, respectively, the maximum recommended human dosage (MRHD) of 60 mg/day given to adolescents on a mg/m² basis. However, spina bifida was observed in rabbits at a dosage 53 times the MRHD given to adolescents. A decrease in pup body weight was observed in a pre-and post-natal development study with oral administration of methylphenidate to rats throughout pregnancy and lactation at dosages 6 times the MRHD given to adolescents (see Data).

The background risk of major birth defects and miscarriage in those with ADHD is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Clinical Considerations
Fetal/Neonatal Adverse Reactions:  CNS stimulants, including Methylphenidate HCl Extended-Release Capsules CD, can cause vasoconstriction and thereby decrease placental perfusion. No fetal and/or neonatal adverse reactions have been reported with the use of a therapeutic dosage of methylphenidate during pregnancy; however, premature delivery and low birth weight infants have been reported in amphetamine-dependent mothers.

Data

Animal Data:  In embryo-fetal development studies conducted in rats and rabbits, methylphenidate was administered orally at dosages of up to 75 and 200 mg/kg/day, respectively, during the period of organogenesis. Malformations (increased incidence of fetal spina bifida) were observed in rabbits at the highest dosage, which is approximately 52 times the MRHD of 60 mg/day given to adolescents on a mg/m² basis. The no effect level for embryo-fetal development in rabbits was 60 mg/kg/day (15 times the MRHD given to adolescents on a mg/m² basis). There was no evidence of morphological development effects in rats, although increased incidences of fetal skeletal variations were seen at the highest dosage level (10 times the MRHD of 60 mg/day given to adults on a mg/m² basis), which was also maternally toxic. The no effect level for embryo-fetal development in rats was 25 mg/kg/day (3 times the MRHD on a mg/m² basis). When methylphenidate was administered to rats throughout pregnancy and lactation at dosages of up to 45 mg/kg/day, offspring body weight gain was decreased at the highest dosage (6 times the MRHD of 60 mg/day given to adults on a mg/m² basis), but no other effects on postnatal development were observed. The no effect level for pre-and postnatal development in rats was 15 mg/kg/day (~2 times the MRHD given to adolescents on a mg/m² basis).

Risk Summary

Limited published literature, based on milk sampling from a small number of methylphenidate-treated lactating women reports that methylphenidate is present in human milk, which resulted in infant dosages of 0.16% to 0.7% of the maternal weight-adjusted dosage and a milk/plasma ratio ranging between 1.1 and 2.7. There are no reports of adverse effects on the breastfed infant and no effects on milk production. Long-term neurodevelopmental effects on infants from stimulant exposure are unknown. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for Methylphenidate HCl Extended-Release Capsules CD and any potential adverse effects on the breastfed infant from Methylphenidate HCl Extended-Release Capsules CD or from the underlying maternal condition.

Clinical Considerations

Monitor breastfeeding infants of Methylphenidate HCl Extended-Release Capsules CD-treated lactating women for adverse reactions, such as agitation, insomnia, anorexia, and reduced weight gain.

The safety and effectiveness of Methylphenidate HCl Extended-Release Capsules CD for the treatment of ADHD have been established in pediatric patients 6 years of age and older.

The safety and effectiveness of Methylphenidate HCl Extended-Release Capsules CD have not been established in pediatric patients below the age of 6 years. In studies evaluating extended-release methylphenidate products, patients 4 to <6 years of age had higher systemic methylphenidate exposures than those observed in older pediatric patients at the same dosage. Pediatric patients 4 to <6 years of age also had a higher incidence of adverse reactions, including weight loss. Therefore, the use of Methylphenidate HCl Extended-Release Capsules CD is not recommended in pediatric patients less than 6 years of age.

Long-Term Suppression of Growth

CNS stimulants have been associated with weight loss and slowing of growth rate in pediatric patients. Growth (weight and height) should be monitored in pediatric patients during treatment with CNS stimulants, including Metadate CD. Pediatric patients who are not growing or gaining weight as expected may need to have their Methylphenidate HCl Extended-Release Capsules CD treatment interrupted [see Warnings and Precautions ( 5.6 )].

Juvenile Animal Toxicity Data

In a study conducted in young rats, methylphenidate was administered orally at dosages of up to 100 mg/kg/day for 9 weeks, starting early in the postnatal period (postnatal Day 7) and continuing through sexual maturity (postnatal Week 10). When these animals were tested as adults (postnatal Weeks 13 to 14), decreased spontaneous locomotor activity was observed in males and females previously treated with 50 mg/kg/day (approximately 6 times the MRHD on a mg/m² basis) or greater, and a deficit in the acquisition of a specific learning task was seen in females exposed to the highest dosage (12 times the MRHD on a mg/m² basis). The no effect level for juvenile neurobehavioral development in rats was 5 mg/kg/day (half the MRHD on a mg/m² basis). The clinical significance of the long-term behavioral effects observed in rats is unknown.

Methylphenidate HCl Extended-Release Capsules CD has not been studied in patients over the age of 65 years and is not indicated for use in adults.

Methylphenidate HCl Extended-Release Capsules CD contains methylphenidate, a Schedule II controlled substance.

Methylphenidate HCl Extended-Release Capsules CD has a high potential for abuse which can lead to the development of a substance use disorder, including addiction [see Warnings and Precautions (5.1)].

Abuse is the intentional non-therapeutic use of a drug, even once, to achieve a desired psychological or physiological effect. Drug addiction is a cluster of behavioral, cognitive, and physiological phenomena that may include a strong desire to take the drug, difficulties in controlling drug use (e.g., continuing drug use despite harmful consequences, giving a higher priority to drug use than other activities and obligations), and possible tolerance or physical dependence.

Methylphenidate HCl Extended-Release Capsules CD has a high potential for misuse. Misuse is the intentional use, for therapeutic purposes, of a drug by an individual in a way other than prescribed by a health care provider or for whom it was not prescribed. Misuse, like abuse, is often associated with higher dosages and/or more frequent use of the drug, which may lead to adverse reactions similar to those seen in the context of abuse and substance use disorder.

Misuse and abuse of methylphenidate may cause increased heart rate, respiratory rate, or blood pressure; sweating; dilated pupils; hyperactivity; restlessness; insomnia; decreased appetite; loss of coordination; tremors; flushed skin; vomiting; and/or abdominal pain. Anxiety, psychosis, hostility, aggression, and suicidal or homicidal ideation have also been observed with CNS stimulants abuse and/or misuse. Misuse and abuse of CNS stimulants, including Methylphenidate HCl Extended-Release Capsules CD, can result in overdose and death [see Overdosage ( 10 )], and this risk is increased with higher dosages or unapproved methods of administration, such as snorting or injection.

Physical Dependence

Methylphenidate HCl Extended-Release Capsules CD may produce physical dependence. Physical dependence is a state that develops as a result of physiological adaptation in response to repeated drug use, manifested by withdrawal signs and symptoms after abrupt discontinuation or a significant dosage reduction of a drug.

Withdrawal signs and symptoms after abrupt discontinuation or dosage reduction following prolonged use of CNS stimulants including Methylphenidate HCl Extended-Release Capsules CD include dysphoric mood; depression; fatigue; vivid; unpleasant dreams; insomnia or hypersomnia; increased appetite; and psychomotor retardation or agitation.

Tolerance

Methylphenidate HCl Extended-Release Capsules CD may produce tolerance. Tolerance is a physiological state characterized by a reduced response to a drug after repeated administration (i.e., a higher dosage of a drug is required to produce the same effect that was once obtained at a lower dosage).

Methylphenidate hydrochloride is a central nervous system (CNS) stimulant. The mode of therapeutic action of Methylphenidate HCl Extended-Release Capsules CD in the treatment of ADHD in pediatric patients 6 years of age and older is not known. Methylphenidate blocks the reuptake of norepinephrine and dopamine into the presynaptic neuron and increases the release of these monoamines into the extraneuronal space.

Methylphenidate is a racemic mixture comprised of the d- and l-threo enantiomers.  The d-threo enantiomer is more pharmacologically active than the l-threo enantiomer. The exposure-response relationship and time course of pharmacodynamic response for the safety and effectiveness of Methylphenidate HCl Extended-Release Capsules CD have not been fully characterized.

Following one week of 20 mg/day or 40 mg/day of Methylphenidate HCl Extended-Release Capsules CD to pediatric patients aged 7 to12 years old with ADHD, C_max and AUC of methylphenidate were approximately proportional to the administered dosage.

Absorption

Following administration of Methylphenidate HCl Extended-Release Capsules CD in pediatric patients aged 7 to 12 years old with ADHD, the plasma concentration time profile of methylphenidate showed two phases of drug release with a sharp, initial slope similar to a methylphenidate immediate-release tablet (median T_max1 about 1.5 hours post dosage), and a second rising portion approximately three hours later (median T_max2 about 4.5 hours post dosage)*, followed by a gradual decline (Figure 1). The means for C_max and area under the curve (AUC) following a dosage of 20 mg of Methylphenidate HCl Extended-Release Capsules CD were slightly lower than those seen with 10 mg of the immediate-release methylphenidate, dosed at 0 and 4 hours.

*25-30% of the patients had only one observed peak (C_max) concentration of methylphenidate.

Figure 1: Methylphenidate Pharmacokinetics After Repeat Dosages of an Immediate Release (IR) Methylphenidate Product and Methylphenidate HCl Extended-Release Capsules CD in Pediatric Patients 7 to 12 Years of Age with ADHD

Effect of Food:  Ingestion of a high-fat meal with Methylphenidate HCl Extended-Release Capsules CD administration increased the mean C_max and AUC of methylphenidate by about 30% and 17%, respectively. The presence of food delayed the early peak by approximately 1 hour (range -2 to 5 hours delay) [ see Dosage and Administration ( 2.1 )].

The bioavailability (C_max and AUC) of methylphenidate was unaffected by sprinkling the Methylphenidate HCl Extended-Release Capsules CD extended-release capsule contents on applesauce as compared to the intact capsule. 

Distribution

Plasma protein binding is 10% to 33%. The volume of distribution was 2.65 ± 1.11 L/kg for d- methylphenidate and 1.80 ± 0.91 L/kg for l- methylphenidate.

Elimination

The mean terminal half-life (t½) of methylphenidate following administration of Methylphenidate HCl Extended-Release Capsules CD (t½=6.8 hours) is longer than the mean terminal t½ following administration of methylphenidate hydrochloride immediate-release tablets (t½=2.9 hours) and methylphenidate hydrochloride extended-release tablets (t½=3.4 hours) in healthy adult volunteers. 

Metabolism:  In vitro studies showed that methylphenidate was not metabolized by cytochrome P450 isoenzymes. Methylphenidate is metabolized primarily by deesterification to alpha-phenyl-piperidine acetic acid (ritalinic acid), which has little or no pharmacologic activity. 

Excretion:  After oral administration of radiolabeled methylphenidate in humans, about 90% of the radioactivity was recovered in urine. The main urinary metabolite was ritalinic acid, accounting for approximately 80% of the dosage. 

Specific Populations

• Male and Female Patients: The pharmacokinetics of methylphenidate after a single dosage of Methylphenidate HCl Extended-Release Capsules CD were similar between adult males and females.
• Patients with Renal Impairment: Methylphenidate HCl Extended-Release Capsules CD has not been studied in patients with renal impairment. Since renal clearance is not an important route of methylphenidate clearance, and the major metabolite (ritalinic acid), has little or no pharmacologic activity, renal impairment is expected to have minimal effect on the pharmacokinetics of methylphenidate after Methylphenidate HCl Extended-Release Capsules CD administration.
• Patients with Hepatic Impairment: Methylphenidate HCl Extended-Release Capsules CD has not been studied in patients with hepatic impairment. Hepatic impairment is expected to have minimal effect on the pharmacokinetics of methylphenidate because it is metabolized primarily to ritalinic acid by nonmicrosomal hydrolytic esterases that are widely distributed throughout the body.
• Racial or Ethnic Groups: The influence of race on the pharmacokinetics of methylphenidate after Methylphenidate HCl Extended-Release Capsules CD administration has not been studied.

Drug Interaction Studies

Alcohol:  An in vitro study was conducted to explore the effect of alcohol on the release characteristics of methylphenidate from the Methylphenidate HCl Extended-Release Capsules CD 60 mg extended-release capsules. At an alcohol concentration of 40%, there was an increase in the release rate of methylphenidate in the first hour, resulting in 84% of the methylphenidate being released. The results with the 60 mg capsule are considered to be representative of the other strengths [see Drug Interactions ( 7 )].

In vitro studies showed that methylphenidate did not inhibit cytochrome P450 isoenzymes at clinically observed plasma drug concentrations.

Carcinogenesis

In a lifetime carcinogenicity study carried out in B6C3F1 mice, methylphenidate caused an increase in hepatocellular adenomas and, in males only, an increase in hepatoblastomas, at a daily dosage of approximately 60 mg/kg per day.  This dosage is approximately 2 times the maximum recommended human dosage (MRHD) of 60 mg/day given to children on a mg/m² basis.  Hepatoblastoma is a relatively rare rodent malignant tumor type.  There was no increase in total malignant hepatic tumors.  The mouse strain used is sensitive to the development of hepatic tumors, and the significance of these results to humans is unknown.

Methylphenidate did not cause any increases in tumors in a lifetime carcinogenicity study carried out in F344 rats; the highest dosage used was approximately 45 mg/kg/day, which is approximately 4 times the MRHD (children) on a mg/m² basis.

In a 24-week carcinogenicity study in the transgenic mouse strain p53+/-, which is sensitive to genotoxic carcinogens, there was no evidence of carcinogenicity.  Male and female mice were fed diets containing the same concentration of methylphenidate as in the lifetime carcinogenicity study; the high-dosage groups were exposed to 60 to 74 mg/kg per day of methylphenidate.

Mutagenesis

Methylphenidate was not mutagenic in the in vitro Ames reverse mutation assay, in the in vitro mouse lymphoma cell forward mutation assay, or in the in vitro chromosomal aberration assay using human lymphocytes.  Sister chromatid exchanges and chromosome aberrations were increased, indicative of a weak clastogenic response, in an in vitro assay in cultured Chinese Hamster Ovary cells.  Methylphenidate was negative in vivo in males and females in the mouse bone marrow micronucleus assay.

Impairment of Fertility

Methylphenidate did not impair fertility in male or female mice that were fed diets containing the drug in an 18-week continuous breeding study.  The study was conducted at dosages up to 160 mg/kg per day, approximately 10 times the maximum recommended human dosage of 60 mg/day given to adolescents on a mg/m² basis.