2.1 Pretreatment Screening

Prior to initiating treatment with RELEXXII, assess for the presence of cardiac disease (i.e., perform a careful history, family history of sudden death or ventricular arrhythmia, and physical exam) [see Warnings and Precautions (5.2)].

Assess the risk of abuse prior to prescribing and monitor for signs of abuse and dependence while on therapy. Maintain careful prescription records, educate patients about abuse, and periodically re-evaluate the need for RELEXXII use [see Boxed Warning, Warning and Precautions (5.1), Drug Abuse and Dependence (9)].

2.2 General Administration Information

Administer RELEXXII orally once daily in the morning with or without food.

Swallow RELEXXII whole with liquid. Do not chew, divide, or crush [see Warnings and Precautions (5.8)].

2.3 Dosage Recommendations for Patients New to Methylphenidate

Table 1 includes the starting dosage and dosage recommendations for RELEXXII in pediatric patients 6 to 17 years and adults who are not currently taking methylphenidate or other stimulants.

Table 1: Dosage Recommendations for RELEXXII in Pediatric Patients 6 to 17 years and Adults

Pharmacological treatment of ADHD may be needed for extended periods. Periodically reevaluate the long-term use of RELEXXII and adjust dosage as needed.

2.4 Dosage Recommendations for Patients Currently Using Methylphenidate

The recommended starting dosage of RELEXXII for patients who are currently taking methylphenidate twice daily or three times daily at doses of 10 mg to 60 mg daily is provided in Table 2.

Table 2. Recommended Starting Dosage when Converting from Methylphenidate Regimens to RELEXXII

2.5 Dose Titration

Doses may be increased in 18 mg increments at weekly intervals for patients who have not achieved clinical response at a lower dose. Daily dosages above 54 mg in pediatric patients 6 to 12 years and above 72 mg in pediatric patients 13 to 17 years have not been studied and are not recommended. Daily dosages above 72 mg are not recommended in adults.

Dosage strengths of 27 mg, 45 mg, and 63 mg are available for additional titration options based on clinical response.

2.6 Dose Reduction and Discontinuation

If paradoxical aggravation of symptoms or other adverse effects occur, reduce the dosage, or, if necessary, discontinue RELEXXII.

If improvement is not observed after appropriate dosage adjustment over a one-month period, discontinue RELEXXII.

5.1 Potential for Abuse and Dependence

CNS stimulants, including RELEXXII, other methylphenidate‑containing products, and amphetamines, have a high potential for abuse and dependence. Assess the risk of abuse prior to prescribing, and monitor for signs of abuse and dependence while on therapy [see Drug Abuse and Dependence (9.2, 9.3)].

5.2 Serious Cardiovascular Reactions

Sudden death, stroke and myocardial infarction have been reported in adults with CNS stimulant treatment at recommended doses. Sudden death has been reported in pediatric patients with structural cardiac abnormalities and other serious heart problems taking CNS stimulants at recommended doses for ADHD. Avoid use in patients with known structural cardiac abnormalities, cardiomyopathy, serious heart rhythm abnormalities, coronary artery disease, and other serious heart problems. Further evaluate patients who develop exertional chest pain, unexplained syncope, or arrhythmias during RELEXXII treatment.

5.3 Blood Pressure and Heart Rate Increases

CNS stimulants cause an increase in blood pressure (mean increase approximately 2 to 4 mm Hg) and heart rate (mean increase approximately 3 to 6 bpm) [see Adverse Reactions (6.1)]. Individuals may have larger increases. Monitor all patients for hypertension and tachycardia.

5.4 Psychiatric Adverse Reactions

Exacerbation of Psychosis

CNS stimulants may exacerbate symptoms of behavior disturbance and thought disorder in patients with a preexisting psychotic disorder.

Induction of a Manic Episode in Patients with Bipolar Disorder

CNS stimulants may induce a manic or mixed episode in patients. Prior to initiating treatment, screen patients for risk factors for developing a manic episode (e.g., comorbid or history of depressive symptoms a family history of suicide, bipolar disorder, and depression).

New Psychotic or Manic Symptoms

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

5.5 Priapism

Prolonged and painful erections, sometimes requiring surgical intervention, have been reported with methylphenidate products, including another formulation of methylphenidate hydrochloride extended-release tablets, in both pediatric and adult patients [see Adverse Reactions (6.2)]. Priapism was not reported with drug initiation but developed after some time on the drug, often subsequent to an increase in dose. Priapism has also appeared during a period of drug withdrawal (drug holidays or during discontinuation). Patients who develop abnormally sustained or frequent and painful erections should seek immediate medical attention.

5.6 Peripheral Vasculopathy, including Raynaud’s Phenomenon

CNS stimulants, such as RELEXXII, used to treat ADHD are associated with peripheral vasculopathy, including Raynaud’s phenomenon. Signs and symptoms are usually intermittent and mild; however, very rare sequelae include digital ulceration and/or soft tissue breakdown. Effects of peripheral vasculopathy, including Raynaud’s phenomenon, were observed in post-marketing reports at different times and at therapeutic doses in all age groups throughout the course of treatment. Signs and symptoms generally improve after reduction in dose or discontinuation of drug. Careful observation for digital changes is necessary during treatment with ADHD stimulants. Further clinical evaluation (e.g., rheumatology referral) may be appropriate for certain patients.

5.7 Long-Term Suppression of Growth

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 nonmedication treatment groups over 14 months, as well as in naturalistic subgroups of newly methylphenidate-treated and nonmedication-treated pediatric patients over 36 months (to the ages of 10 to 13 years), suggests that consistently medicated pediatric patients (i.e., treatment for 7 days per week throughout the year) have 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 period of development.

Closely monitor growth (weight and height) in pediatric patients treated with stimulants, including RELEXXII. Patients who are not growing or gaining height or weight as expected may need to have their treatment interrupted.

5.8 Potential for Gastrointestinal Obstruction

Because the RELEXXII tablet is nondeformable and does not appreciably change in shape in the GI tract, RELEXXII should not ordinarily be administered to patients with preexisting severe gastrointestinal narrowing (pathologic or iatrogenic, for example: esophageal motility disorders, small bowel inflammatory disease, "short gut" syndrome due to adhesions or decreased transit time, past history of peritonitis, cystic fibrosis, chronic intestinal pseudo-obstruction, or Meckel's diverticulum). There have been rare reports of obstructive symptoms in patients with known strictures in association with the ingestion of drugs in nondeformable controlled-release formulations. Due to the extended-release design of the tablet, RELEXXII should be used only in patients who are able to swallow the tablet whole [see Patient Counseling Information (17)].

6.1 Clinical Trials Experience

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 clinical trials of another drug and may not reflect the rates observed in clinical practice.

The safety of RELEXXII for the treatment of ADHD is based on adequate and well-controlled studies of another formulation of methylphenidate hydrochloride extended-release tablets. Below is a display of adverse reactions from those adequate and well-controlled studies in ADHD.

Adults and pediatric patients 6 to 17 years with ADHD were evaluated in six controlled clinical studies and eleven open-label clinical studies (see Table 3). Safety was assessed by collecting adverse reactions, vital signs, weights, and electrocardiograms (ECGs), and by performing physical examinations and laboratory analyses. A total of 3,906 patients participated in the clinical trials.

Table 3. Exposure in Double-Blind and Open-Label Clinical Studies of Another Formulation of Methylphenidate Hydrochloride Extended-Release Tablets

* 108 mg is 1.5 times the maximum recommended dosage of RELEXXII.

The most common adverse reactions in double-blind clinical trials (>5%) were:

• Pediatric patients 6 to 17 years: abdominal pain upper (see Table 4).
• Adults: decreased appetite, headache, dry mouth, nausea, insomnia, anxiety, dizziness, weight decreased, irritability, and hyperhidrosis (see Table 5).

The most common adverse reactions associated with discontinuation (≥1%) from either pediatric or adult clinical trials were anxiety, irritability, insomnia, and blood pressure increased.

Adverse reactions in either the pediatric or adult double-blind adverse reactions tables may be relevant for both patient populations.

Pediatric Patients 6 to 17 Years

Table 4 lists the adverse reactions reported in 1% or more of another formulation of methylphenidate hydrochloride extended-release tablet-treated pediatric patients (6 to 17 years) in four placebo-controlled, double-blind clinical trials.

Table 4. Adverse Reactions Reported by ≥1% of Pediatric Patients (6 to 17 years) Treated with Another Formulation of Methylphenidate Hydrochloride Extended-release Tablets in Four Placebo-Controlled, Double-Blind Clinical Trials

Adults

Table 5 lists the adverse reactions reported in 1% or more of adults treated with another formulation of methylphenidate hydrochloride extended-release tablets in two placebo-controlled, double-blind clinical trials.

Table 5. Adverse Reactions Reported by ≥1% of Adults Treated with Another Formulation of Methylphenidate Hydrochloride Extended-release Tablets in Two Placebo-Controlled, Double-Blind Clinical Trials*

Adverse Reactions Observed in Clinical Trials with Another Formulation of Methylphenidate Hydrochloride Extended-release Tablets

This section includes adverse reactions reported with use of another formulation of methylphenidate hydrochloride extended-release tablets in double-blind trials that do not meet the criteria specified for Table 4 or Table 5 and all adverse reactions reported by the other formulation of methylphenidate hydrochloride extended-release tablets-treated patients who participated in open-label and postmarketing clinical trials.

Blood and Lymphatic System Disorders: Leukopenia

Eye Disorders: Accommodation disorder, Dry eye

Vascular Disorders: Hot flush

Gastrointestinal Disorders: Abdominal discomfort, Abdominal pain, Diarrhea

General Disorders and Administrative Site Conditions: Asthenia, Fatigue, Feeling jittery, Thirst

Infections and Infestations: Sinusitis

Investigations: Alanine aminotransferase increased, Blood pressure increased, Cardiac murmur, Heart rate increased

Musculoskeletal and Connective Tissue Disorders: Muscle spasms

Nervous System Disorders: Lethargy, Psychomotor hyperactivity, Somnolence

Psychiatric Disorders: Anger, Hypervigilance, Mood altered, Mood swings, Panic attack, Sleep disorder, Tearfulness, Tic

Reproductive System and Breast Disorders: Erectile dysfunction

Respiratory, Thoracic and Mediastinal Disorders: Dyspnea

Skin and Subcutaneous Tissue Disorders: Rash, Rash macular

Vascular Disorders: Hypertension

Discontinuation Due to Adverse Reactions

Adverse reactions in the four placebo-controlled studies of pediatric patients (6 to 17 years) leading to discontinuation occurred in 2 patients (0.6%) treated with another formulation of methylphenidate hydrochloride extended-release tablets including depressed mood (1, 0.3%) and headache and insomnia (1, 0.3%), and 6 placebo patients (1.9%) including headache and insomnia (1, 0.3%), irritability (2, 0.6%), headache (1, 0.3%), psychomotor hyperactivity (1, 0.3%), and tic (1, 0.3%).

In the two placebo-controlled studies of adults, 25 patients (6.0%) treated with another formulation of methylphenidate hydrochloride extended-release tablets and 6 placebo patients (2.8%) discontinued due to an adverse reaction. Incidence of >0.5% in patients treated with another formulation of methylphenidate hydrochloride extended-release tablets included anxiety (1.7%), irritability (1.4%), blood pressure increased (1.0%), and nervousness (0.7%). In placebo patients, blood pressure increased and depressed mood had an incidence of >0.5% (0.9%).

In the eleven open-label studies of pediatric patients and adults, 266 patients (7.0%) treated with another formulation of methylphenidate hydrochloride extended-release tablets discontinued due to an adverse reaction. Incidence of >0.5% included insomnia (1.2%), irritability (0.8%), anxiety (0.7%), decreased appetite (0.7%), and tic (0.6%).

Tics

In a long-term uncontrolled study (n=432 pediatric patients 6 to 12 years), the cumulative incidence of new onset of tics was 9% after 27 months of treatment with another formulation of methylphenidate hydrochloride extended-release tablets.

In a second uncontrolled study (n=682 pediatric patients 6 to 12 years) the cumulative incidence of new-onset tics was 1% (9/682). The treatment period was up to 9 months with mean treatment duration of 7.2 months.

Blood Pressure and Heart Rate Increases

In the laboratory classroom clinical trials in pediatric patients 6 to 12 years (Studies 1 and 2), both another formulation of methylphenidate hydrochloride extended-release tablets once daily and methylphenidate three times daily increased resting pulse by an average of 2 to 6 bpm and produced average increases of systolic and diastolic blood pressure of roughly 1 to 4 mm Hg during the day, relative to placebo. In the placebo-controlled trial in pediatric patients 13 to 17 years (Study 4), mean increases from baseline in resting pulse rate were observed with another formulation of methylphenidate hydrochloride extended-release tablets and placebo at the end of the double-blind phase (5 and 3 beats/minute, respectively). Mean increases from baseline in blood pressure at the end of the double-blind phase for another formulation of methylphenidate hydrochloride extended-release tablets and placebo-treated patients were 0.7 and 0.7 mm Hg (systolic) and 2.6 and 1.4 mm Hg (diastolic), respectively. In one placebo-controlled study in adults (Study 6), dose-dependent mean increases of 3.9 to 9.8 bpm from baseline in standing pulse rate were observed with another formulation of methylphenidate hydrochloride extended-release tablets at the end of the double-blind treatment vs. an increase of 2.7 beats/minute with placebo. Mean changes from baseline in standing blood pressure at the end of double-blind treatment ranged from 0.1 to 2.2 mm Hg (systolic) and -0.7 to 2.2 mm Hg (diastolic) for another formulation of methylphenidate hydrochloride extended-release tablets and was 1.1 mm Hg (systolic) and -1.8 mm Hg (diastolic) for placebo. In a second placebo-controlled study in adults (Study 5), mean changes from baseline in resting pulse rate were observed for another formulation of methylphenidate hydrochloride extended-release tablets and placebo at the end of the double-blind treatment (3.6 and –1.6 beats/minute, respectively). Mean changes from baseline in blood pressure at the end of the double–blind treatment for another formulation of methylphenidate hydrochloride extended-release tablets and placebo-treated patients were –1.2 and –0.5 mm Hg (systolic) and 1.1 and 0.4 mm Hg (diastolic), respectively [see Warnings and Precautions (5.3)].

6.2 Postmarketing Experience

The following additional adverse reactions have been identified during post-approval use of another formulation of methylphenidate hydrochloride extended-release tablets. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Blood and Lymphatic System Disorders: Pancytopenia, Thrombocytopenia, Thrombocytopenic purpura

Cardiac Disorders: Angina pectoris, Bradycardia, Extrasystoles, Supraventricular tachycardia, Ventricular extrasystoles

Eye Disorders: Diplopia, Mydriasis, Visual impairment

General Disorders: Chest pain, Chest discomfort, Drug effect decreased, Hyperpyrexia, Therapeutic response decreased

Hepatobiliary Disorders: Hepatocellular injury, Acute hepatic failure

Immune System Disorders: Hypersensitivity reactions such as Angioedema, Anaphylactic reactions, Auricular swelling, Bullous conditions, Exfoliative conditions, Urticarias, Pruritus NEC, Rashes, Eruptions, and Exanthemas NEC

Investigations: Blood alkaline phosphatase increased, Blood bilirubin increased, Hepatic enzyme increased, Platelet count decreased, White blood cell count abnormal

Musculoskeletal, Connective Tissue and Bone Disorders: Arthralgia, Myalgia, Muscle twitching, Rhabdomyolysis

Nervous System Disorders: Convulsion, Grand mal convulsion, Dyskinesia, Serotonin syndrome in combination with serotonergic drugs

Psychiatric Disorders: Disorientation, Hallucination, Hallucination auditory, Hallucination visual, Mania, Logorrhea, Libido changes

Reproductive System and Breast Disorders: Priapism

Skin and Subcutaneous Tissue Disorders: Alopecia, Erythema

Vascular Disorders: Raynaud's phenomenon

7.1 Clinically Important Drug Interactions

Table 6 presents clinically important drug interactions with RELEXXII.

Table 6: Drugs Having Clinically Important Interactions with RELEXXII

8.1 Pregnancy

Pregnancy Exposure Registry

There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ADHD medications, including RELEXXII, during pregnancy. Healthcare providers are encouraged to register patients by calling the National Pregnancy Registry for ADHD Medications at 1-866-961-2388.

Risk Summary

Published studies and post-marketing reports on methylphenidate use during pregnancy have not identified 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 development studies with oral administration of methylphenidate to pregnant rats at doses up to 4 times the maximum recommended human dose (MRHD) of 72 mg/day given to adults on a mg/m2 basis. However, malformations were observed in rabbits at a dose 54 times the MRHD given to adults.

The estimated background risk of major birth defects and miscarriage for the indicated population 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, such as RELEXXII, can cause vasoconstriction and thereby decrease placental perfusion. No fetal and/or neonatal adverse reactions have been reported with the use of therapeutic doses of methylphenidate during pregnancy; however, premature delivery and low birth weight infants have been reported in amphetamine‑dependent mothers.

Data

Animal Data

In development studies conducted in rats and rabbits, methylphenidate was administered at doses up to 30 and 200 mg/kg/day, respectively. Methylphenidate has been shown to cause malformations in rabbits when given in doses of 200 mg/kg/day, which is approximately 54 times the MRHD on a mg/m2 basis, respectively. A reproduction study in rats revealed no evidence of harm to the fetus at oral doses up to 30 mg/kg/day, approximately 4-fold the MRHD on a mg/m2 basis.

8.2 Lactation

Risk Summary

Limited published literature, based on breast milk sampling from five mothers, reports that methylphenidate is present in human milk, which resulted in infant doses 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. However, long‑term neurodevelopmental effects on infants from CNS stimulant exposure are unknown. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for RELEXXII and any potential adverse effects on the breastfed infant from RELEXXII or from the underlying maternal condition.

Clinical Considerations

Monitor breastfeeding infants for adverse reactions, such as agitation, anorexia, and reduced weight gain.

8.4 Pediatric Use

The safety and effectiveness of RELEXXII for the treatment of ADHD have been established in pediatric patients 6 to 17 years.

The safety and effectiveness of RELEXXII in pediatric patients less than 6 years have not been established.

The long-term efficacy of methylphenidate in pediatric patients have not been established.

Long Term Suppression of Growth

Growth should be monitored during treatment with stimulants, including RELEXXII. Pediatric patients who are not growing or gaining weight as expected may need to have their treatment interrupted [see Warnings and Precautions (5.7) and Adverse Reactions (6.1)].

Juvenile Animal Toxicity Data

In the study conducted in young rats, methylphenidate was administered orally at doses 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 13-14), decreased spontaneous locomotor activity was observed in males and females previously treated with 50 mg/kg/day (approximately 4 times the MRHD of 54 mg/day given to children on a mg/m2 basis) or greater, and a deficit in the acquisition of a specific learning task was observed in females exposed to the highest dose (9 times the MRHD given to children on a mg/m2 basis). The no effect level for juvenile neurobehavioral development in rats was 5 mg/kg/day (equal to the MRHD given to children on a mg/m2 basis). The clinical significance of the long-term behavioral effects observed in rats is unknown.

8.5 Geriatric Use

RELEXXII has not been studied in patients greater than 65 years of age.

9.1 Controlled Substance

RELEXXII contains methylphenidate, a Schedule II controlled substance.

9.2 Abuse

CNS stimulants, including RELEXXII, other methylphenidate-containing products, and amphetamines have a high potential for abuse. 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. Both abuse and misuse may lead to addiction, and some individuals may develop addiction even when taking RELEXXII as prescribed.

Signs and symptoms of CNS stimulant abuse include increased heart rate, respiratory rate, blood pressure, and/or sweating, dilated pupils, hyperactivity, restlessness, insomnia, decreased appetite, loss of coordination, tremors, flushed skin, vomiting, and/or abdominal pain. Anxiety, psychosis, hostility, aggression, suicidal or homicidal ideation have also been observed. Individuals who abuse CNS stimulants may chew, snort, inject, or use other unapproved routes of administration which can result in overdose and death [see Overdosage (10)].

To reduce the abuse of RELEXXII, assess the risk of abuse prior to prescribing. After prescribing, keep careful prescription records, educate patients and their families about abuse and on proper storage and disposal of CNS stimulants [see How Supplied/Storage and Handling (16)], monitor for signs of abuse while on therapy, and re-evaluate the need for RELEXXII use.

In two placebo-controlled human abuse potential studies, single oral doses of another formulation of methylphenidate hydrochloride extended-release tablets were compared to single oral doses of immediate-release methylphenidate (IR MPH) and placebo in subjects with a history of recreational stimulant use to assess relative abuse potential. For the purpose of this assessment, the response for each of the subjective measures was defined as the maximum effect within the first 8 hours after dose administration.

In one study (n=40), both the other formulation of methylphenidate hydrochloride extended-release tablets (108 mg, which is 1.5 times the maximum recommended dosage of methylphenidate hydrochloride extended-release tablets) and 60 mg IR MPH compared to placebo produced statistically significantly greater responses on the five subjective measures suggestive of abuse potential. In comparisons between the two active treatments, however, the other formulation of methylphenidate hydrochloride extended-release tablets (108 mg) produced variable responses on positive subjective measures that were either statistically indistinguishable from (Abuse Potential, Drug Liking, Amphetamine, and Morphine Benzedrine Group [Euphoria]) or statistically less than (Stimulation – Euphoria) responses produced by 60 mg IR MPH.

In another study (n=49), both doses of another formulation of methylphenidate hydrochloride extended-release tablets (54 mg and 108 mg) and both doses of IR MPH (50 mg and 90 mg) produced statistically significantly greater responses compared to placebo on the two primary scales used in the study (Drug Liking, Euphoria). When doses of the other methylphenidate hydrochloride extended-release tablets (54 mg and 108 mg) were compared to IR MPH (50 mg and 90 mg), respectively, methylphenidate hydrochloride extended-release tablets produced statistically significantly lower subjective responses on these two scales than IR MPH. Methylphenidate hydrochloride extended-release tablets (108 mg) produced responses that were statistically indistinguishable from the responses on these two scales produced by IR MPH (50 mg). Differences in subjective responses to the respective doses should be considered in the context that only 18% of the total amount of methylphenidate in RELEXXII is available for immediate release from the drug overcoat.

Although these findings reveal a relatively lower response to another formulation of methylphenidate hydrochloride extended-release tablets on subjective measures suggestive of abuse potential compared to IR MPH at roughly equivalent total MPH doses, the relevance of these findings to the abuse potential of RELEXXII in the community is unknown.

9.3 Dependence

Physical Dependence

RELEXXII may produce physical dependence from continued therapy. Physical dependence is a state of adaptation manifested by a withdrawal syndrome produced by abrupt cessation, rapid dose reduction, or administration of an antagonist. Withdrawal symptoms after abrupt cessation following prolonged high-dosage administration of CNS stimulants include dysphoric mood; depression; fatigue; vivid, unpleasant dreams; insomnia or hypersomnia; increased appetite; and psychomotor retardation or agitation.

Tolerance

RELEXXII may produce tolerance from continued therapy. Tolerance is a state of adaptation in which exposure to a drug results in a reduction of the drug’s desired and/or undesired effects over time.

12.1 Mechanism of Action

Methylphenidate HCl is a CNS stimulant. The mode of therapeutic action in ADHD is not known.

12.2 Pharmacodynamics

Methylphenidate is a racemic mixture comprised of the d- and l-threo entantiomers. The d-threo enantiomer is more pharmacologically active than the l-threo enantiomer. Methylphenidate blocks the reuptake of norepinephrine and dopamine into the presynaptic neuron and increase the release of these monoamines into the extraneuronal space.

12.3 Pharmacokinetics

In a relative bioavailability study in healthy adults under fasted conditions, plasma exposures of 72 mg RELEXXII and 72 mg (2 x 36 mg) methylphenidate extended-release tablets were compared. The peak plasma concentration (Cmax) of RELEXXII and methylphenidate extended-release tablets is 19.7 ng/mL and 19.3 ng/mL, respectively. The area under the plasma concentration-time curve (AUC0-inf) of RELEXXII and methylphenidate extended-release tablets is 206.1 ng∙h/mL and 200.9 ng∙h/mL, respectively.

Absorption

Methylphenidate is readily absorbed. Following oral administration of RELEXXII plasma methylphenidate concentrations increase rapidly, reaching an initial maximum at about 1.5 hour, followed by gradual ascending concentrations over the next 5 to 6 hours, after which a gradual decrease begins. Mean time to reach peak plasma concentrations of RELEXXII occurs at 5.5 hours.

Methylphenidate hydrochloride extended-release tablets once daily minimizes the fluctuations between peak and trough concentrations associated with immediate-release methylphenidate three times daily. Figure 1 displays mean plasma exposures of methylphenidate hydrochloride extended-release tablets once daily and methylphenidate three times daily (administered every 4 hours) in adults.

Figure 1. Mean Methylphenidate Plasma Concentration-Time Profiles

The mean single-dose pharmacokinetic parameters in 36 healthy adults following the administration of methylphenidate hydrochloride extended-release tablets 18 mg once daily and methylphenidate 5 mg three times daily are summarized in Table 7.

Table 7. Methylphenidate Pharmacokinetic Parameters (Mean ± SD) After Single Dose in Healthy Adults

The pharmacokinetics of methylphenidate hydrochloride extended-release tablets were evaluated in healthy adults following single- and multiple-dose administration (steady state) of doses up to 144 mg per day (2 times the maximum recommended daily dosage of methylphenidate hydrochloride extended-release tablets). The mean half-life was about 3.6 hours. No differences in the pharmacokinetics of methylphenidate hydrochloride extended-release tablets were noted following single and repeated once-daily dosing, indicating no significant drug accumulation. The AUC and t1/2 following repeated once-daily dosing are similar to those following the first dose of methylphenidate hydrochloride extended-release tablets in a dose range of 18 mg to 144 mg.

Effect of Food

There were no differences in either the pharmacokinetics or the pharmacodynamic performance of methylphenidate hydrochloride extended-release tablets when administered after a high-fat breakfast. There is no evidence of dose dumping in the presence or absence of food.

Effect of Alcohol

In-vitro studies were conducted to explore the effect of alcohol on the release characteristics of methylphenidate from RELEXXII. At alcohol concentrations up to 40%, there was no increased release of methylphenidate in the first two hours.

Dose Proportionality

Following administration methylphenidate hydrochloride extended-release tablets in single doses of 18 mg, 36 mg, and 54 mg per day to healthy adults, Cmax and AUC (0–inf) of d-methylphenidate were proportional to dose, whereas l-methylphenidate Cmax and AUC (0–inf) increased disproportionately with respect to dose. Following administration of methylphenidate hydrochloride extended-release tablets, plasma concentrations of the l-isomer were approximately 1/40 the plasma concentrations of the d-isomer.

In healthy adults, single and multiple dosing of once-daily methylphenidate hydrochloride extended-release tablets doses from 54 mg to 144 mg per day resulted in linear and dose-proportional increases in Cmax and AUCinf for total methylphenidate (MPH) and its major metabolite, α-phenyl-piperidine acetic acid (PPAA). There was no time dependency in the pharmacokinetics of methylphenidate. The ratio of metabolite (PPAA) to parent drug (MPH) was constant across doses from 54 mg to 144 mg per day, both after single dose and upon multiple dosing.

In a multiple-dose study in ADHD with pediatric patients 13 to 16 years administered their prescribed dose (18 mg to 72 mg per day) of methylphenidate hydrochloride extended-release tablets, mean Cmax and AUCTAU of d- and total methylphenidate increased proportionally with respect to dose.

Distribution

Plasma methylphenidate concentrations in adults and pediatric patients 13 to 17 years decline biexponentially following oral administration. The half-life of methylphenidate in adults and adolescents following oral administration of methylphenidate hydrochloride extended-release tablets was approximately 3.5 hours.

Elimination

Metabolism

In humans, methylphenidate is metabolized primarily by de-esterification to PPAA, which has little or no pharmacologic activity. In adults the metabolism of methylphenidate hydrochloride extended-release tablets once daily as evaluated by metabolism to PPAA is similar to that of methylphenidate three times daily. The metabolism of single and repeated once-daily doses of methylphenidate hydrochloride extended-release tablets is similar.

Excretion

After oral dosing of radiolabeled methylphenidate in humans, about 90% of the radioactivity was recovered in urine. The main urinary metabolite was PPAA, accounting for approximately 80% of the dose.

Specific Populations

Male and Female Patients

In healthy adults, the mean dose-adjusted AUC (0–inf) values for methylphenidate hydrochloride extended-release tablets were 36.7 ng∙h/mL in men and 37.1 ng∙h/mL in women, with no differences noted between the two groups.

Racial or Ethnic Groups

In adults receiving methylphenidate hydrochloride extended-release tablets, dose-adjusted AUC (0–inf) was consistent across ethnic groups; however, the sample size may have been insufficient to detect ethnic variations in pharmacokinetics.

Pediatric Patients

Increase in age resulted in increased apparent oral clearance (CL/F) (58% increase in pediatric patients 13 to 17 years compared to pediatric patients 6 to 12 years). Some of these differences could be explained by body-weight differences among these populations. This suggests that subjects with higher body weight may have lower exposures of total methylphenidate at similar doses.

The pharmacokinetics of methylphenidate hydrochloride extended-release tablets have not been studied in pediatric patients less than 6 years of age.

Patients with Renal Impairment

There is no experience with the use of methylphenidate hydrochloride extended-release tablets in patients with renal insufficiency. After oral administration of radiolabeled methylphenidate in humans, methylphenidate was extensively metabolized and approximately 80% of the radioactivity was excreted in the urine in the form of PPAA. Since renal clearance is not an important route of methylphenidate clearance, renal insufficiency is expected to have little effect on the pharmacokinetics of methylphenidate hydrochloride extended-release tablets.

Patients with Hepatic Impairment

There is no experience with the use of methylphenidate hydrochloride extended-release tablets in patients with hepatic insufficiency.

13.1 Carcinogenesis, Mutagenesis, and Impairment of Fertility

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 dose of approximately 60 mg/kg/day. This dose is approximately 4 times the MRHD of methylphenidate hydrochloride extended-release tablets on a mg/m2 basis, respectively. 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 dose used was approximately 45 mg/kg/day, which is approximately 6 times the MRHD of methylphenidate hydrochloride extended-release tablets on a mg/m2 basis, respectively.

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-dose groups were exposed to 60 to 74 mg/kg/day of methylphenidate.

Mutagenesis

Methylphenidate was not mutagenic in the in vitro Ames reverse mutation assay or the in vitro mouse lymphoma cell forward mutation assay. 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 doses up to 160 mg/kg/day, approximately 11-fold the MRHD of methylphenidate hydrochloride extended-release tablets on a mg/m2 basis, respectively.