Paliperidone Drug Information

Schizophrenia Paliperidone extended-release tablets are indicated for the treatment of schizophrenia.

The efficacy of paliperidone extended-release tablets in schizophrenia was established in three 6-week trials in adults and one 6-week trial in adolescents, as well as one maintenance trial in adults.

Schizoaffective Disorder Paliperidone extended-release tablets are indicated for the treatment of schizoaffective

disorder as monotherapy and an adjunct to mood stabilizers and/or antidepressant therapy . The efficacy of paliperidone in schizoaffective disorder was established in two 6-week trials in adults.

Clinical Trials Experience

The most common adverse reactions in clinical trials in adult subjects with schizophrenia (reported in 5% or more of subjects treated with paliperidone and at least twice the placebo rate in any of the dose groups) were extrapyramidal symptoms, tachycardia, and akathisia. The most common adverse reactions in clinical trials in adult patients with schizoaffective disorder (reported in 5% or more of subjects treated with paliperidone and at least twice the placebo rate) were extrapyramidal symptoms, somnolence, dyspepsia, constipation, weight increased, and nasopharyngitis. The most common adverse reactions that were associated with discontinuation from clinical trials in adult subjects with schizophrenia (causing discontinuation in 2% of paliperidone-treated subjects) were nervous system disorders.

The most common adverse reactions that were associated with discontinuation from clinical trials in adult subjects with schizoaffective disorder were gastrointestinal disorders, which resulted in discontinuation in 1% of paliperidone-treated subjects. The safety of paliperidone was evaluated in 1205 adult subjects with schizophrenia who participated in three placebo-controlled, 6-week, double-blind trials, of whom 850 subjects received paliperidone at fixed doses ranging from 3 mg to 12 mg once daily. The information presented in this section was derived from pooled data from these three trials.

Additional safety information from the placebo-controlled phase of the long-term maintenance study, in which subjects received paliperidone at daily doses within the range of 3 mg to 15 mg (n=104), is also included. The safety of paliperidone was evaluated in 150 adolescent subjects 12 to 17 years of age with schizophrenia who received paliperidone in the dose range of 1.5 mg to 12 mg/day in a 6-week, double-blind, placebo-controlled trial. The safety of paliperidone was also evaluated in 622 adult subjects with schizoaffective disorder who participated in two placebo-controlled, 6-week, double-blind trials.

In one of these trials, 206 subjects were assigned to one of two dose levels of paliperidone: 6 mg with the option to reduce to 3 mg (n = 108) or 12 mg with the option to reduce to 9 mg (n = 98) once daily. In the other study, 214 subjects received flexible doses of paliperidone (3 to 12 mg once daily). Both studies included subjects who received paliperidone either as monotherapy or as an adjunct to mood stabilizers and/or antidepressants. Adverse events during exposure to study treatment were obtained by general inquiry and recorded by clinical investigators using their own terminology.

Consequently, to provide a meaningful estimate of the proportion of individuals experiencing adverse events, events were grouped in standardized categories using MedDRA terminology. Throughout this section, adverse reactions are reported. Adverse reactions are adverse events that were considered to be reasonably associated with the use of paliperidone (adverse drug reactions) based on the comprehensive assessment of the available adverse event information.

A causal association for paliperidone often cannot be reliably established in individual cases. Further, 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 clinical practice. Commonly-Observed Adverse Reactions in Double-Blind, Placebo-Controlled Clinical Trials – Schizophrenia in Adults and Adolescents Adult Patients with Schizophrenia Table 4 enumerates the pooled incidences of adverse reactions reported in the three placebo-controlled, 6-week, fixed-dose studies in adults, listing those that occurred in 2% or more of subjects treated with paliperidone in any of the dose groups, and for which the incidence in paliperidone-treated subjects in any of the dose groups was greater than the incidence in subjects treated with placebo.

Table 4. Adverse Reactions Reported by ≥ 2% of Paliperidone-Treated Adult Subjects with Schizophrenia in Three Short-Term, Fixed-Dose, Placebo-Controlled Clinical Trials * Percentage of Patients Paliperidone Placebo 3 mg once daily 6 mg once daily 9 mg once daily 12 mg once daily Body System or Organ Class (N=355) (N=127) (N=235) (N=246) (N=242) Dictionary-Derived Term Total percentage of subjects with adverse reactions 37 48 47 53 59 Cardiac disorders Atrioventricular block first degree 1 2 0 2 1 Bundle branch block 2 3 1 3 <1 Sinus arrhythmia 0 2 1 1 <1 Tachycardia 7 14 12 12 14 Gastrointestinal disorders Abdominal pain upper 1 1 3 2 2 Dry mouth 1 2 3 1 3 Salivary hypersecretion <1 0 <1 1 4 General disorders Asthenia 1 2 <1 2 2 Fatigue 1 2 1 2 2 Nervous system disorders Akathisia 4 4 3 8 10 Dizziness 4 6 5 4 5 Extrapyramidal symptoms 8 10 7 20 18 Headache 12 11 12 14 14 Somnolence 7 6 9 10 11 Vascular disorders Orthostatic hypotension 1 2 1 2 4 * Table includes adverse reactions that were reported in 2% or more of subjects in any of the paliperidone dose groups and which occurred at greater incidence than in the placebo group. Data are pooled from three studies; one study included once-daily paliperidone doses of 3 mg and 9 mg, the second study included 6 mg, 9 mg, and 12 mg, and the third study included 6 mg and 12 mg. Extrapyramidal symptoms includes the terms dyskinesia, dystonia, extrapyramidal disorder, hypertonia, muscle rigidity, oculogyration, parkinsonism, and tremor.

Somnolence includes the terms sedation and somnolence. Tachycardia includes the terms tachycardia, sinus tachycardia, and heart rate increased. Adverse reactions for which the paliperidone incidence was equal to or less than placebo are not listed in the table, but included the following: vomiting.

Adolescent Patients with Schizophrenia Table 5 lists the adverse reactions reported in a fixed-dose, placebo-controlled study in adolescent subjects 12 to 17 years of age with schizophrenia, listing those that occurred in 2% or more of subjects treated with paliperidone in any of the dose groups, and for which the incidence in paliperidone-treated subjects in any of the dose groups was greater than the incidence in subjects treated with placebo. Table 5. Adverse Reactions Reported by ≥ 2% of Paliperidone-Treated Adolescent Subjects with Schizophrenia in a Fixed-Dose, Placebo-Controlled Clinical Trial * Percentage of Patients Paliperidone Placebo 1.5 mg once daily 3 mg once daily 6 mg once daily 12 mg once daily Body System or Organ Class (N=51) (N=54) (N=16) (N=45) (N=35) Dictionary-Derived Term Total percentage of subjects with adverse reactions 43 37 50 58 74 Cardiac disorders Tachycardia 0 0 6 9 6 Eye disorders Vision blurred 0 0 0 0 3 Gastrointestinal disorders Dry mouth 2 0 0 0 3 Salivary hypersecretion 0 2 6 2 0 Swollen tongue 0 0 0 0 3 Vomiting 10 0 6 11 3 General disorders Asthenia 0 0 0 2 3 Fatigue 0 4 0 2 3 Infections and infestations Nasopharyngitis 2 4 0 4 0 Investigations Weight increased 0 7 6 2 3 Nervous system disorders Akathisia 0 4 6 11 17 Dizziness 0 2 6 2 3 Extrapyramidal symptoms 0 4 19 18 23 Headache 4 9 6 4 14 Lethargy 0 0 0 0 3 Somnolence 4 9 13 20 26 Tongue paralysis 0 0 0 0 3 Psychiatric disorders Anxiety 4 0 0 2 9 Reproductive system and breast disorders Amenorrhea 0 0 6 0 0 Galactorrhea 0 0 0 4 0 Gynecomastia 0 0 0 0 3 Respiratory, thoracic and mediastinal disorders Epistaxis 0 0 0 2 0 * Table includes adverse reactions that were reported in 2% or more of subjects in any of the paliperidone dose groups and which occurred at greater incidence than in the placebo group. Extrapyramidal symptoms includes the terms oculogyric crisis, muscle rigidity, musculoskeletal stiffness, nuchal rigidity, torticollis, trismus, bradykinesia, cogwheel rigidity, dyskinesia, dystonia, extrapyramidal disorder, hypertonia, hypokinesia, muscle contractions involuntary, parkinsonian gait, parkinsonism, tremor, and restlessness.

Somnolence includes the terms somnolence, sedation, and hypersomnia. Insomnia includes the terms insomnia and initial insomnia. Tachycardia includes the terms tachycardia, sinus tachycardia, and heart rate increased.

Hypertension includes the terms hypertension and blood pressure increased. Gynecomastia includes the terms gynecomastia and breast swelling. Commonly-Observed Adverse Reactions in Double-Blind, Placebo-Controlled Clinical Trials – Schizoaffective Disorder in Adults Table 6 enumerates the pooled incidences of adverse reactions reported in the two placebo-controlled 6-week studies in adult subjects, listing those that occurred in 2% or more of subjects treated with paliperidone and for which the incidence in paliperidone-treated subjects was greater than the incidence in subjects treated with placebo.

Table 6. Adverse Drug Reactions Reported by > 2% of Paliperidone-Treated Adult Subjects with Schizoaffective Disorder in Two Double-Blind, Placebo-Controlled Clinical Trials * Percentage of Patients Placebo Paliperidone 3 to 6 mg once-daily fixed-dose range Paliperidone 9 to 12 mg once-daily fixed-dose range Paliperidone 3 to 12 mg once-daily flexible dose Body System or Organ Class (N=202) (N=108) (N=98) (N=214) Dictionary-Derived Term Total percentage of subjects with adverse reactions 32 48 50 43 Cardiac disorders Tachycardia 2 3 1 2 Gastrointestinal disorders Abdominal discomfort/Abdominal pain upper 1 1 0 3 Constipation 2 4 5 4 Dyspepsia 2 5 6 6 Nausea 6 8 8 5 Stomach discomfort 1 0 1 2 General disorders Asthenia 1 3 4 <1 Infections and Infestations Nasopharyngitis 1 2 5 3 Rhinitis 0 1 3 1 Upper respiratory tract infection 1 2 2 2 Investigations Weight increased 1 5 4 4 Metabolism and nutrition disorders Decreased appetite <1 1 0 2 Increased appetite <1 3 2 2 Musculoskeletal and connective tissue disorders Back pain 1 1 1 3 Myalgia <1 2 4 1 Nervous system disorders Akathisia 4 4 6 6 Dysarthria 0 1 4 2 Extrapyramidal symptoms 8 20 17 12 Somnolence 5 12 12 8 Psychiatric disorders Sleep disorder <1 2 3 0 Respiratory, thoracic and mediastinal disorders Cough 1 1 3 1 Pharyngolaryngeal pain <1 0 2 1 * Table includes adverse reactions that were reported in 2% or more of subjects in any of the paliperidone dose groups and which occurred at greater incidence than in the placebo group. Data are pooled from two studies. One study included once-daily paliperidone doses of 6 mg (with the option to reduce to 3 mg) and 12 mg (with the option to reduce to 9 mg). The second study included flexible once-daily doses of 3 to 12 mg.

Among the 420 subjects treated with paliperidone, 230 (55%) received paliperidone as monotherapy and 190 (45%) received paliperidone as an adjunct to mood stabilizers and/or antidepressants. Extrapyramidal symptoms includes the terms bradykinesia, drooling, dyskinesia, dystonia, hypertonia, muscle rigidity, muscle twitching, oculogyration, parkinsonian gait, parkinsonism, restlessness, and tremor. Somnolence includes the terms sedation and somnolence.

Tachycardia includes the terms tachycardia, sinus tachycardia, and heart rate increased. Monotherapy versus Adjunctive Therapy The designs of the two placebo-controlled, 6-week, double-blind trials in adult subjects with schizoaffective disorder included the option for subjects to receive antidepressants (except monoamine oxidase inhibitors) and/or mood stabilizers (lithium, valproate, or lamotrigine). In the subject population evaluated for safety, 230 (55%) subjects received paliperidone as monotherapy and 190 (45%) subjects received paliperidone as an adjunct to mood stabilizers and/or antidepressants. When comparing these 2 subpopulations, only nausea occurred at a greater frequency (≥ 3% difference) in subjects receiving paliperidone as monotherapy.

Discontinuations Due to Adverse Reactions Schizophrenia Trials The percentages of subjects who discontinued due to adverse reactions in the three schizophrenia placebo-controlled, 6-week, fixed-dose studies in adults were 3% and 1% in paliperidone- and placebo-treated subjects, respectively. The most common reasons for discontinuation were nervous system disorders (2% and 0% in paliperidone- and placebo-treated subjects, respectively). Among the adverse reactions in the 6-week, fixed-dose, placebo-controlled study in adolescents with schizophrenia, only dystonia led to discontinuation (<1% of paliperidone-treated subjects). Schizoaffective Disorder Trials The percentages of subjects who discontinued due to adverse reactions in the two schizoaffective disorder placebo‑controlled 6-week studies in adults were 1% and <1% in paliperidone- and placebo-treated subjects, respectively. The most common reasons for discontinuation were gastrointestinal disorders (1% and 0% in paliperidone- and placebo-treated subjects, respectively). Dose-Related Adverse Reactions Schizophrenia Trials Based on the pooled data from the three placebo-controlled, 6-week, fixed-dose studies in adult subjects with schizophrenia, among the adverse reactions that occurred with a greater than 2% incidence in the subjects treated with paliperidone, the incidences of the following adverse reactions increased with dose: somnolence, orthostatic hypotension, akathisia, dystonia, extrapyramidal disorder, hypertonia, parkinsonism, and salivary hypersecretion.

For most of these, the increased incidence was seen primarily at the 12 mg dose, and, in some cases, the 9 mg dose. In the 6-week, fixed-dose, placebo-controlled study in adolescents with schizophrenia, among the adverse reactions that occurred with >2% incidence in the subjects treated with paliperidone, the incidences of the following adverse reactions increased with dose: tachycardia, akathisia, extrapyramidal symptoms, somnolence, and headache. Schizoaffective Disorder Trials In a placebo-controlled, 6-week, high- and low-dose study in adult subjects with schizoaffective disorder, akathisia, dystonia, dysarthria, myalgia, nasopharyngitis, rhinitis, cough, and pharyngolaryngeal pain occurred more frequently (i.e., a difference of at least 2%) in subjects who received higher doses of paliperidone compared with subjects who received lower doses.

Demographic Differences An examination of population subgroups in the three placebo-controlled, 6-week, fixed-dose studies in adult subjects with schizophrenia and in the two placebo-controlled, 6-week studies in adult subjects with schizoaffective disorder did not reveal any evidence of clinically relevant differences in safety on the basis of gender or race alone; there was also no difference on the basis of age. Extrapyramidal Symptoms (EPS) Pooled data from the three placebo-controlled, 6-week, fixed-dose studies in adult subjects with schizophrenia provided information regarding treatment-emergent EPS. Several methods were used to measure EPS: the Simpson-Angus global score (mean change from baseline) which broadly evaluates Parkinsonism, the Barnes Akathisia Rating Scale global clinical rating score (mean change from baseline) which evaluates akathisia, use of anticholinergic medications to treat emergent EPS (Table 7), and incidence of spontaneous reports of EPS (Table 8). For the Simpson-Angus Scale, spontaneous EPS reports and use of anticholinergic medications, there was a dose-related increase observed for the 9 mg and 12 mg doses. There was no difference observed between placebo and paliperidone 3 mg and 6 mg doses for any of these EPS measures.

Table 7. Treatment-Emergent Extrapyramidal Symptoms (EPS) Assessed by Incidence of Ratings Scales and Use of Anticholinergic Medication - Schizophrenia Studies in Adults Percentage of Patients Paliperidone Placebo 3 mg once daily 6 mg once daily 9 mg once daily 12 mg once daily EPS Group (N=355) (N=127) (N=235) (N=246) (N=242) Parkinsonism a 9 11 3 15 14 Akathisia b 6 6 4 7 9 Use of anticholinergic medications c 10 10 9 22 22 a For Parkinsonism, percent of patients with Simpson-Angus global score > 0.3 (Global score defined as total sum of items score divided by the number of items) b For Akathisia, percent of patients with Barnes Akathisia Rating Scale global score ≥ 2 c Percent of patients who received anticholinergic medications to treat emergent EPS Table 8. Treatment-Emergent Extrapyramidal Symptoms (EPS)-Related Adverse Events by MedDRA Preferred Term – Schizophrenia Studies in Adults Percentage of Patients Paliperidone Placebo 3 mg once daily 6 mg once daily 9 mg once daily 12 mg once daily EPS Group (N=355) (N=127) (N=235) (N=246) (N=242) Overall percentage of patients with EPS-related AE 11 13 10 25 26 Dyskinesia 3 5 3 8 9 Dystonia 1 1 1 5 5 Hyperkinesia 4 4 3 8 10 Parkinsonism 2 3 3 7 6 Tremor 3 3 3 4 3 Dyskinesia group includes: Dyskinesia, extrapyramidal disorder, muscle twitching, tardive dyskinesia Dystonia group includes: Dystonia, muscle spasms, oculogyration, trismus Hyperkinesia group includes: Akathisia, hyperkinesia Parkinsonism group includes: Bradykinesia, cogwheel rigidity, drooling, hypertonia, hypokinesia, muscle rigidity, musculoskeletal stiffness, parkinsonism Tremor group includes: Tremor Compared to data from the studies in adults subjects with schizophrenia, pooled data from the two placebo-controlled 6-week studies in adult subjects with schizoaffective disorder showed similar types and frequencies of EPS as measured by rating scales, anticholinergic medication use, and spontaneous reports of EPS-related adverse events. For subjects with schizoaffective disorder, there was no dose-related increase in EPS observed for parkinsonism with the Simpson-Angus scale or akathisia with the Barnes Akathisia Rating Scale. There was a dose-related increase observed with spontaneous EPS reports of hyperkinesia and dystonia and in the use of anticholinergic medications.

Table 9 shows the EPS data from the pooled schizoaffective disorder trials. Table 9. Treatment-Emergent Extrapyramidal Symptoms (EPS)-Related Adverse Events by MedDRA Preferred Term – Schizoaffective Disorder Studies in Adults Percentage of Patients Paliperidone Placebo 3 to 6 mg once-daily fixed-dose range 9 to 12 mg once-daily fixed-dose range 3 to 12 mg once-daily flexible dose EPS Group (N=202) (N=108) (N=98) (N=214) Overall percentage of patients with EPS-related AE 11 23 22 17 Dyskinesia 1 3 1 1 Dystonia 1 2 3 2 Hyperkinesia 5 5 8 7 Parkinsonism 3 14 7 7 Tremor 3 12 11 5 Dyskinesia group includes: Dyskinesia, muscle twitching Dystonia group includes: Dystonia, muscle spasms, oculogyration Hyperkinesia group includes: Akathisia, hyperkinesia, restlessness Parkinsonism group includes: Bradykinesia, drooling, hypertonia, muscle rigidity, muscle tightness, musculoskeletal stiffness, parkinsonian gait, parkinsonism Tremor group includes: Tremor The incidences of EPS-related adverse events in the adolescent schizophrenia studies showed a similar dose-related pattern to those in the adult studies. There were notably higher incidences of dystonia, hyperkinesia, tremor, and parkinsonism in the adolescent population as compared to the adult studies (Table 10). Table 10. Treatment-Emergent Extrapyramidal Symptoms (EPS)-Related Adverse Events by MedDRA Preferred Term – Schizophrenia Studies in Adolescent Subjects Percentage of Patients Paliperidone Placebo 1.5 mg once daily 3 mg once daily 6 mg once daily 12 mg once daily EPS Group (N=51) (N=54) (N=16) (N=45) (N=35) Overall percentage of patients with EPS-related AE 0 6 25 22 40 Hyperkinesia 0 4 6 11 17 Dystonia 0 2 0 11 14 Tremor 0 2 6 7 11 Parkinsonism 0 0 6 2 14 Dyskinesia 0 2 6 2 6 Hyperkinesia group includes: Akathisia Dystonia group includes: Dystonia, muscle contracture, oculogyric crisis, tongue paralysis, torticollis Tremor group includes: Tremor Parkinsonism group includes: Cogwheel rigidity, extrapyramidal disorder, muscle rigidity Dyskinesia group includes: Dyskinesia, muscle contractions involuntary Dystonia Class Effect: Symptoms of dystonia, prolonged abnormal contractions of muscle groups, may occur in susceptible individuals during the first few days of treatment.

Dystonic symptoms include: spasm of the neck muscles, sometimes progressing to tightness of the throat, swallowing difficulty, difficulty breathing, and/or protrusion of the tongue. While these symptoms can occur at low doses, they occur more frequently and with greater severity with high potency and at higher doses of first generation antipsychotic drugs. An elevated risk of acute dystonia is observed in males and younger age groups.

Laboratory Test Abnormalities In the pooled data from the three placebo-controlled, 6-week, fixed-dose studies in adult subjects with schizophrenia and from the two placebo-controlled, 6-week studies in adult subjects with schizoaffective disorder, between-group comparisons revealed no medically important differences between paliperidone and placebo in the proportions of subjects experiencing potentially clinically significant changes in routine serum chemistry, hematology, or urinalysis parameters. Similarly, there were no differences between paliperidone and placebo in the incidence of discontinuations due to changes in hematology, urinalysis, or serum chemistry, including mean changes from baseline in fasting glucose, insulin, c-peptide, triglyceride, HDL, LDL, and total cholesterol measurements. However, paliperidone was associated with increases in serum prolactin.

Other Adverse Reactions Observed During Premarketing Evaluation of Paliperidone The following additional adverse reactions occurred in < 2% of paliperidone-treated subjects in the above schizophrenia and schizoaffective disorder clinical trial datasets. The following also includes additional adverse reactions reported at any frequency by paliperidone-treated subjects who participated in other clinical studies. Cardiac disorders: bradycardia, palpitations Eye disorders: eye movement disorder Gastrointestinal disorders: flatulence General disorders: edema Immune system disorders: anaphylactic reaction Infections and infestations: urinary tract infection Investigations: alanine aminotransferase increased, aspartate aminotransferase increased Musculoskeletal and connective tissue disorders: arthralgia, pain in extremity Nervous system disorders: opisthotonus Psychiatric disorders: agitation, insomnia, nightmare Reproductive system and breast disorders: breast discomfort, menstruation irregular, retrograde ejaculation Respiratory, thoracic and mediastinal disorders: nasal congestion Skin and subcutaneous tissue disorders: pruritus, rash Vascular disorders: hypertension The safety of paliperidone was also evaluated in a long-term trial designed to assess the maintenance of effect with paliperidone in adults with schizophrenia.

In general, adverse reaction types, frequencies, and severities during the initial 14-week open-label phase of this study were comparable to those observed in the 6-week, placebo-controlled, fixed-dose studies. Adverse reactions reported during the long-term double-blind phase of this study were similar in type and severity to those observed in the initial 14-week open-label phase.

Postmarketing Experience

The following adverse reactions have been identified during postapproval use of paliperidone; because these reactions were reported voluntarily from a population of uncertain size, it is not possible to reliably estimate their frequency: angioedema, catatonia, ileus, priapism, somnambulism, swollen tongue, tardive dyskinesia, thrombotic thrombocytopenic purpura, urinary incontinence, urinary retention.

Adverse Reactions Reported with Risperidone Paliperidone is the major active metabolite of

risperidone. Adverse reactions reported with risperidone can be found in the ADVERSE REACTIONS section of the risperidone package insert.

Potential for Paliperidone to Affect Other Drugs Given the primary

CNS effects of paliperidone , paliperidone should be used with caution in combination with other centrally acting drugs and alcohol. Paliperidone may antagonize the effect of levodopa and other dopamine agonists. Because of its potential for inducing orthostatic hypotension, an additive effect may be observed when paliperidone is administered with other therapeutic agents that have this potential.

Paliperidone is not expected to cause clinically important pharmacokinetic interactions with drugs that are metabolized by cytochrome P450 isozymes. In vitro studies in human liver microsomes showed that paliperidone does not substantially inhibit the metabolism of drugs metabolized by cytochrome P450 isozymes, including CYP1A2, CYP2A6, CYP2C8/9/10, CYP2D6, CYP2E1, CYP3A4, and CYP3A5. Therefore, paliperidone is not expected to inhibit clearance of drugs that are metabolized by these metabolic pathways in a clinically relevant manner. Paliperidone is also not expected to have enzyme inducing properties.

Paliperidone is a weak inhibitor of P-glycoprotein (P-gp) at high concentrations. No in vivo data are available and the clinical relevance is unknown. Pharmacokinetic interaction between lithium and paliperidone is unlikely.

In a drug interaction study, co-administration of paliperidone (12 mg once daily for 5 days) with divalproex sodium extended-release tablets (500 mg to 2000 mg once daily) did not affect the steady-state pharmacokinetics (AUC 24h and C max,ss ) of valproate in 13 patients stabilized on valproate. In a clinical study, subjects on stable doses of valproate had comparable valproate average plasma concentrations when paliperidone 3 to 15 mg/day was added to their existing valproate treatment.

Potential for Other Drugs to Affect Paliperidone Paliperidone is not a substrate

of CYP1A2, CYP2A6, CYP2C9, and CYP2C19, so that an interaction with inhibitors or inducers of these isozymes is unlikely. While in vitro studies indicate that CYP2D6 and CYP3A4 may be minimally involved in paliperidone metabolism, in vivo studies do not show decreased elimination by these isozymes and they contribute to only a small fraction of total body clearance. In vitro studies have shown that paliperidone is a P-gp substrate.

Co-administration of paliperidone 6 mg once daily with carbamazepine, a strong inducer of both CYP3A4 and P-glycoprotein (P-gp), at 200 mg twice daily caused a decrease of approximately 37% in the mean steady-state C max and AUC of paliperidone. This decrease is caused, to a substantial degree, by a 35% increase in renal clearance of paliperidone. A minor decrease in the amount of drug excreted unchanged in the urine suggests that there was little effect on the CYP metabolism or bioavailability of paliperidone during carbamazepine co-administration.

On initiation of carbamazepine, the dose of paliperidone should be re-evaluated and increased if necessary. Conversely, on discontinuation of carbamazepine, the dose of paliperidone should be re-evaluated and decreased if necessary. Paliperidone is metabolized to a limited extent by CYP2D6 . In an interaction study in healthy subjects in which a single 3 mg dose of paliperidone was administered concomitantly with 20 mg per day of paroxetine (a potent CYP2D6 inhibitor), paliperidone exposures were on average 16% (90% CI: 4, 30) higher in CYP2D6 extensive metabolizers.

Higher doses of paroxetine have not been studied. The clinical relevance is unknown. Co-administration of a single dose of paliperidone 12 mg with divalproex sodium extended-release tablets (two 500 mg tablets once daily) resulted in an increase of approximately 50% in the C max and AUC of paliperidone.

Dosage reduction for paliperidone should be considered when paliperidone is co-administered with valproate after clinical assessment. Pharmacokinetic interaction between lithium and paliperidone is unlikely.

Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to atypical antipsychotics, including paliperidone, during pregnancy. Healthcare providers are encouraged to register patients by contacting the National Pregnancy Registry for Atypical Antipsychotics at 1-866-961-2388 or online at http://womensmentalhealth.org/clinical-and-research-programs/pregnancyregistry/. Risk Summary Neonates exposed to antipsychotic drugs during the third trimester of pregnancy are at risk for extrapyramidal and/or withdrawal symptoms following delivery (see Clinical Considerations ). Overall, available data from published epidemiologic studies of pregnant women exposed to paliperidone have not established a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes (see Data ). There are risks to the mother associated with untreated schizophrenia and with exposure to antipsychotics, including paliperidone, during pregnancy (see Clinical Considerations ). The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defects, 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. In animal reproduction studies, there were no increases in fetal abnormalities when pregnant rats and rabbits were treated with paliperidone during the period of organogenesis with up to 8 times the maximum recommended human dose (MRHD) based on mg/m 2 body surface area. Additional reproduction toxicity studies were conducted with orally administered risperidone, which is extensively converted to paliperidone (see Animal data ). Clinical Considerations Disease-associated maternal and/or embryo/fetal risk There is a risk to the mother from untreated schizophrenia, including increased risk of relapse, hospitalization, and suicide.

Schizophrenia are associated with increased adverse perinatal outcomes, including preterm birth. It is not known if this is a direct result of the illness or other comorbid factors. Fetal/Neonatal Adverse Reactions Extrapyramidal and/or withdrawal symptoms, including agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, and feeding disorder have been reported in neonates who were exposed to antipsychotic drugs, including paliperidone, during the third trimester of pregnancy.

These symptoms have varied in severity. Monitor neonates for extrapyramidal and/or withdrawal symptoms and manage symptoms appropriately. Some neonates recovered within hours or days without specific treatment; others required prolonged hospitalization.

Data Human Data Published data from observational studies, birth registries, and case reports on the use of atypical antipsychotics during pregnancy do not report a clear association with antipsychotics and major birth defects. A prospective observational study including 6 women treated with risperidone, the parent compound of paliperidone, demonstrated placental passage of risperidone and paliperidone. A retrospective cohort study from a Medicaid database of 9258 women exposed to antipsychotics during pregnancy did not indicate an overall increased risk for major birth defects.

There was a small increase in the risk of major birth defects (RR= 1.26, 95% CI 1.02-1.56) and of cardiac malformations (RR=1.26, 95% CI 0.88-1.81) in a subgroup of 1566 women exposed to the parent compound of paliperidone, risperidone, during the first trimester of pregnancy; however, there is no mechanism of action to explain the difference in malformation rates. Animal Data In animal reproduction studies, there were no increases in fetal abnormalities when pregnant rats and rabbits were treated with paliperidone during the period of organogenesis with up to 8 times the MRHD of 12 mg based on mg/m 2 body surface area. Additional reproduction toxicity studies were conducted with orally administered risperidone, which is extensively converted to paliperidone.

Cleft palate was observed in the offspring of pregnant mice treated with risperidone at 3 to 4 times the MRHD of 16 mg based on mg/m 2 body surface area; maternal toxicity occurred at 4 times the MHRD. There was no evidence of teratogenicity in embryo-fetal developmental toxicity studies with risperidone in rats and rabbits at doses up to 6 times the MRHD of 16 mg/day risperidone based on mg/m 2 body surface area. When the offspring of pregnant rats, treated with risperidone at 0.6 times the MRHD based on mg/m 2 body surface area, reached adulthood, learning was impaired. Increased neuronal cell death occurred in the fetal brains of the offspring of pregnant rats treated at 0.5 to 1.2 times the MRHD; the postnatal development and growth of the offspring was delayed.

In rat reproduction studies with risperidone, pup deaths occurred at oral doses which are less than the MRHD of risperidone based on mg/m 2 body surface area; it is not known whether these deaths were due to a direct effect on the fetuses or pups or to effects on the dams (see risperidone package insert).

Pediatric Use Safety and effectiveness of paliperidone in the treatment of schizophrenia were evaluated in 150 adolescent subjects 12 to 17 years of age with schizophrenia who received paliperidone in the dose range of 1.5 mg to 12 mg/day in a 6-week, double-blind, placebo-controlled trial. Safety and effectiveness of paliperidone for the treatment of schizophrenia in patients < 12 years of age have not been established. Safety and effectiveness of paliperidone for the treatment of schizoaffective disorder in patients < 18 years of age have not been studied.

Juvenile Animal Studies In a study in which juvenile rats were treated with oral paliperidone from days 24 to 73 of age, a reversible impairment of performance in a test of learning and memory was seen, in females only, with a no-effect dose of 0.63 mg/kg/day, which produced plasma levels (AUC) of paliperidone similar to those in adolescents at MRHD of 12 mg/day. No other consistent effects on neurobehavioral or reproductive development were seen up to the highest dose tested (2.5 mg/kg/day), which produced plasma levels of paliperidone 2 to 3 times those in adolescents. Juvenile dogs were treated for 40 weeks with oral risperidone, which is extensively metabolized to paliperidone in animals and humans, at doses of 0.31, 1.25, or 5 mg/kg/day.

Decreased bone length and density were seen with a no-effect dose of 0.31 mg/kg/day, which produced plasma levels (AUC) of risperidone plus paliperidone which were similar to those in children and adolescents receiving the MRHD of risperidone. In addition, a delay in sexual maturation was seen at all doses in both males and females. The above effects showed little or no reversibility in females after a 12-week drug-free recovery period.

The long-term effects of paliperidone on growth and sexual maturation have not been fully evaluated in children and adolescents.

Paliperidone extended-release tablets are contraindicated in patients with a known hypersensitivity to either paliperidone or risperidone, or to any of the excipients in the paliperidone extended-release tablet formulation. Hypersensitivity reactions, including anaphylactic reactions and angioedema, have been reported in patients treated with risperidone and in patients treated with paliperidone. Paliperidone is a metabolite of risperidone.

Known hypersensitivity to paliperidone, risperidone, or to any excipients in paliperidone.

Human Experience

While experience with paliperidone overdose is limited, among the few cases of overdose reported in pre-marketing trials, the highest estimated ingestion of paliperidone was 405 mg. Observed signs and symptoms included extrapyramidal symptoms and gait unsteadiness. Other potential signs and symptoms include those resulting from an exaggeration of paliperidone’s known pharmacological effects, i.e., drowsiness and somnolence, tachycardia and hypotension, and QT prolongation.

Torsade de pointes and ventricular fibrillation have been reported in a patient in the setting of overdose. Paliperidone is the major active metabolite of risperidone. Overdose experience reported with risperidone can be found in the OVERDOSAGE section of the risperidone package insert.

Management of Overdosage

There is no specific antidote to paliperidone, therefore, appropriate supportive measures should be instituted and close medical supervision and monitoring should continue until the patient recovers. Consideration should be given to the extended-release nature of the product when assessing treatment needs and recovery. Multiple drug involvement should also be considered.

In case of acute overdose, establish and maintain an airway and ensure adequate oxygenation and ventilation. Administration of activated charcoal together with a laxative should be considered. The possibility of obtundation, seizures, or dystonic reaction of the head and neck following overdose may create a risk of aspiration with induced emesis.

Cardiovascular monitoring should commence immediately, including continuous electrocardiographic monitoring for possible arrhythmias. If antiarrhythmic therapy is administered, disopyramide, procainamide, and quinidine carry a theoretical hazard of additive QT-prolonging effects when administered in patients with an acute overdose of paliperidone. Similarly, the alpha-blocking properties of bretylium might be additive to those of paliperidone, resulting in problematic hypotension.

Hypotension and circulatory collapse should be treated with appropriate measures, such as intravenous fluids and/or sympathomimetic agents (epinephrine and dopamine should not be used, since beta stimulation may worsen hypotension in the setting of paliperidone-induced alpha blockade). In cases of severe extrapyramidal symptoms, anticholinergic medication should be administered.