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2 DOSAGE AND ADMINISTRATION See Full Prescribing Information for complete dosing instructions ( 2.1 - 2.7 ). Dosage for Adult Patients with Narcolepsy • Initiate dosage at 4.5 g per night orally, divided into two doses ( 2.1 ). • Titrate to effect in increments of up to 1.5 g per night per week ( 2.1 ). • Recommended dosage range: 6 g to 9 g per night orally, divided into two doses ( 2.1 ). • Doses may be divided equally or unequally and the first dose taken at bedtime and the second dose taken 2.5 to 4 hours later ( 2.1 ). Dosage for Pediatric Patients with Narcolepsy (7 Years of Age and Older) • The recommended starting dosage, titration regimen, and maximum total nightly dosage are based on body weight (2.2 ). Dosage for Adult Patients with Idiopathic Hypersomnia • XYWAV can be administered as a twice or once nightly regimen in adults ( 2.3 ). • Twice nightly: Initiate dosage at 4.5 g or less per night orally, divided into two doses. Titrate to effect in increments of up to 1.5 g per night per week, up to 9 g total nightly dose ( 2.3 ). • Once nightly: Initiate dosage at 3 g or less per night orally, as one dose. Titrate to effect in increments of up to 1.5 g per night per week, up to 6 g total nightly dose ( 2.3 ). Important Administration Information • Administer XYWAV at least 2 hours after eating ( 2.4 ). • Prepare XYWAV prior to bedtime; dilute with approximately ¼ cup of water in pharmacy-provided containers ( 2.4 ). • Take XYWAV while in bed and lie down after dosing ( 2.4 ). For Patients Transitioning from Xyrem to XYWAV: Initiate at the same dose and regimen as Xyrem (gram for gram). Titrate as needed based on efficacy and tolerability ( 2.5 ). Patients with Hepatic Impairment Recommended starting dosage is one-half of the original dosage per night administered orally, divided into two doses ( 2.6 ). 2.1 Dosing Information in Adult Patients with Narcolepsy The recommended starting dosage is 4.5 grams (g) per night administered orally, divided into two doses: 2.25 g at bedtime and 2.25 g taken 2.5 to 4 hours later (see Table 1). Increase the dosage by up to 1.5 g per night per week (e.g., 0.75 g at bedtime and 0.75 g taken 2.5 to 4 hours later), to the recommended dosage range of 6 g to 9 g per night. The dosage may be gradually titrated based on efficacy and tolerability. Some patients may achieve better responses with unequal doses at bedtime and 2.5 to 4 hours later. Doses higher than 9 g per night have not been studied and ordinarily should not be administered. Table 1: Recommended Adult XYWAV Dosage Regimen (g = grams) Note: Some patients may achieve better responses with unequal nightly doses at bedtime and 2.5 to 4 hours later. If a Patient’s Total Nightly Dosage Is: Take at Bedtime: Take 2.5 to 4 Hours Later: 4.5 g per night 2.25 g 2.25 g 6 g per night 3 g 3 g 7.5 g per night 3.75 g 3.75 g 9 g per night 4.5 g 4.5 g 2.2 Dosing Information in Pediatric Patients with Narcolepsy For pediatric patients 7 years of age and older, XYWAV is administered orally twice per night. The recommended starting pediatric dosage, titration regimen, and maximum total nightly dosage are based on patient weight, as specified in Table 2. The dosage may be gradually titrated based on efficacy and tolerability. Doses higher than 9 g per night have not been studied and ordinarily should not be administered. Table 2: Recommended XYWAV Dosage for Patients 7 Years of Age and Older* * For patients who sleep more than 8 hours per night, the first nightly dose of XYWAV may be given at bedtime or after an initial period of sleep. ** If XYWAV is used in patients 7 years of age and older who weigh less than 20 kg, a lower starting dosage, lower maximum weekly dosage increases, and lower total maximum nightly dosage should be considered. Note: Some patients may achieve better responses with unequal nightly doses at bedtime and 2.5 to 4 hours later. Patient Weight Initial Dosage Maximum Weekly Dosage Increase Maximum Recommended Dosage Take at Bedtime: Take 2.5 to 4 Hours Later: Take at Bedtime: Take 2.5 to 4 Hours Later: Take at Bedtime: Take 2.5 to 4 Hours Later: <20 kg** There is insufficient information to provide specific dosing recommendations for patients who weigh less than 20 kg. 20 kg to <30 kg ≤1 g ≤1 g 0.5 g 0.5 g 3 g 3 g 30 kg to <45 kg ≤1.5 g ≤1.5 g 0.5 g 0.5 g 3.75 g 3.75 g ≥45 kg ≤2.25 g ≤2.25 g 0.75 g 0.75 g 4.5 g 4.5 g 2.3 Dosing Information in Adult Patients with Idiopathic Hypersomnia (IH) The dosage and regimen of XYWAV should be individualized based on clinical presentation [see Clinical Studies ( 14.3 )] . XYWAV can be administered as a twice nightly or once nightly regimen. The recommended starting dose, titration guidance, and maximum nightly doses appear in Table 3: Table 3: Recommended Nightly Dosage in Adult Patients with IH * Some patients may achieve better responses with unequal nightly doses at bedtime and 2.5 to 4 hours later. † The first dose should be taken at bedtime and the second dose taken 2.5 to 4 hours later. Dosing Regimen Starting Nightly Dose Titration Increments Maximum Total Nightly Dose Twice nightly *,† ≤4.5 g per night divided into two doses (e.g., 2.25 g each) ≤1.5 g per night per week (divided into two doses) 9 g (divided into two doses) Once nightly ≤3 g per night ≤1.5 g per night per week 6 g The increase in the total nightly dose should not exceed 1.5 g /week. During titration, the dosing regimen may be changed between twice nightly and once nightly, as needed based on efficacy and tolerability [see Clinical Studies ( 14.3 )] . Doses higher than 9 g per night or single dose administrations higher than 6 g have not been studied and should not be administered. 2.4 Important Administration Instructions for All Patients Administer XYWAV at least 2 hours after eating [see Clinical Pharmacology ( 12.3 )] . Prepare all doses of XYWAV prior to bedtime. Prior to ingestion, each dose of XYWAV should be diluted with approximately ¼ cup (approximately 60 mL) of water in the empty pharmacy-provided containers. Solutions prepared following dilution should be consumed within 24 hours. Patients should take each dose of XYWAV while in bed and lie down immediately after dosing, and remain in bed following ingestion of each dose. XYWAV may cause patients to fall asleep abruptly without first feeling drowsy [see Adverse Reactions ( 6.2 )] . Patients will often fall asleep within 5 minutes of taking XYWAV, and will usually fall asleep within 15 minutes, though the time it takes any individual patient to fall asleep may vary from night to night. If dosing twice nightly, patients may need to set an alarm to awaken for the second dose. If the second dose is missed, that dose should be skipped and XYWAV should not be taken again until the next night. Two XYWAV doses should never be taken at one time. 2.5 Patients Transitioning from Xyrem to XYWAV On the first night of dosing with XYWAV, initiate treatment at the same dose (gram for gram) and regimen as Xyrem. Titrate as needed based on efficacy and tolerability [see Dosage and Administration ( 2.1 )] . 2.6 Dosage Modification in Patients with Hepatic Impairment The recommended starting dosage in patients with hepatic impairment is one-half of the original dosage per night administered orally, divided into two doses [see Use in Specific Populations ( 8.6 ) and Clinical Pharmacology ( 12.3 )] . 2.7 Dosage Adjustment with Co-administration of Divalproex Sodium When initiating divalproex sodium in patients taking a stable dosage of XYWAV, a reduction of the XYWAV dosage by at least 20% is recommended with initial concomitant use [see Drug Interactions ( 7.2 ) and Clinical Pharmacology ( 12.3 )] . When initiating XYWAV in patients already taking divalproex sodium, a lower starting dosage of XYWAV is recommended. Subsequently, the dosage of XYWAV can be adjusted based on individual clinical response and tolerability.
Side Effects Overview
6 ADVERSE REACTIONS The following clinically significant adverse reactions appear in other sections of the labeling: • CNS depression [see Warnings and Precautions ( 5.1 )] • Abuse and Misuse [see Warnings and Precautions ( 5.2 )] • Respiratory Depression and Sleep-Disordered Breathing [see Warnings and Precautions ( 5.4 )] • Depression and Suicidality [see Warnings and Precautions ( 5.5 )] • Other Behavioral or Psychiatric Adverse Reactions [see Warnings and Precautions ( 5.6 )] • Parasomnias [see Warnings and Precautions ( 5.7 )] Most common adverse reactions in adults with narcolepsy or IH (≥5%) were nausea, headache, dizziness, anxiety, insomnia, decreased appetite, hyperhidrosis, vomiting, diarrhea, dry mouth, parasomnia, somnolence, fatigue, and tremor ( 6.1 ). In a pediatric study with sodium oxybate (same active moiety as XYWAV), the most common adverse reactions (≥5%) were nausea, enuresis, vomiting, headache, weight decreased, decreased appetite, dizziness, and sleepwalking ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Jazz Pharmaceuticals, Inc. at 1-800-520-5568, or FDA at 1-800-FDA-1088 or www.fda.gov/Medwatch . 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 the clinical trials of another drug and may not reflect the rates observed in clinical practice. Adult Patients with Narcolepsy The safety of XYWAV was evaluated in a 16‑week double-blind placebo-controlled randomized-withdrawal study in patients with narcolepsy with cataplexy (Study 1), which was followed by an open-label extension phase lasting 24 weeks [see Clinical Studies ( 14.1 )] . Study 1 included an open‑label titration period (OL OTTP), a stable-dose period (SDP), and a double‑blind, placebo‑controlled, randomized-withdrawal period (DB RWP). A total of 201 patients, ages 18 to 70 years, received XYWAV at individually titrated doses for 14 weeks, followed by randomization to XYWAV or matching placebo for 2 weeks of treatment. The mean exposure to XYWAV during this study, including titration, the randomized withdrawal period, and the open-label extension, was 151 days. In patients who remained on treatment, adverse reactions tended to occur early and diminish over time. Adverse Reactions Leading to Treatment Discontinuation in Study 1 In Study 1, 9 of 201 patients (4%) reported adverse reactions that led to withdrawal from the study (anxiety, decreased appetite, depressed mood, depression, fatigue, headache, irritability, nausea, pain in extremity, parasomnia, somnolence, and vomiting). The most common adverse reaction leading to discontinuation was nausea (1.5%). The majority of adverse reactions leading to discontinuation began during the first few weeks of treatment. Commonly Observed Adverse Reactions The most common adverse reactions in Study 1 (incidence ≥5% of XYWAV-treated patients) were headache, nausea, dizziness, decreased appetite, parasomnia, diarrhea, hyperhidrosis, anxiety, and vomiting. Adverse Reactions Occurring at an Incidence of 2% or Greater: Table 4 lists adverse reactions observed in the open-label titration and stable dose periods of Study 1 that occurred at a frequency of 2% or greater in adult patients treated with XYWAV. Table 4: Adverse Reactions Occurring in ≥2% of Adult Patients Treated with XYWAV in the Open-Label Titration and Stable Dose Periods in Study 1 * * Adverse reactions related to XYWAV were reported less frequently, as an overall incidence, in patients on Xyrem at study entry than in Xyrem-naïve patients. † Includes abnormal dreams, abnormal sleep-related event, rapid eye movements sleep abnormal, sleep paralysis, sleep talking, sleep terror, sleep-related eating disorder, somnambulism ‡ Includes hyperhidrosis and night sweats § Includes anxiety, agitation, panic attack, tension ¶ Includes fatigue and asthenia Adverse Reaction Open-Label Titration Period + Stable Dose Period (14 weeks) (N=201) % Headache 20 Nausea 13 Dizziness 10 Decreased appetite 8 Parasomnia † 6 Diarrhea 6 Hyperhidrosis ‡ 6 Anxiety § 5 Vomiting 5 Fatigue ¶ 4 Dry mouth 4 Depressed mood 4 Enuresis 4 Irritability 3 Paresthesia 3 Depression 3 Tremor 3 Somnolence 2 Muscle spasms 2 Pediatric Patients (7 Years of Age and Older) with Narcolepsy In the pediatric clinical trial with Xyrem (same active moiety as XYWAV), 104 patients aged 7 to 17 years (37 patients aged 7 to 11 years; 67 patients aged 12 to 17 years) with narcolepsy received Xyrem for up to one year [see Clinical Studies ( 14.2 )] . This study included an open-label safety continuation period in which eligible patients received Xyrem for up to an additional 2 years. The median and maximum exposure across the entire study were 371 and 987 days, respectively. Adverse Reactions Leading to Treatment Discontinuation In the pediatric clinical trial with Xyrem, 7 of 104 patients reported adverse reactions that led to withdrawal from the study (hallucination, tactile; suicidal ideation; weight decreased; sleep apnea syndrome; affect lability; anger, anxiety, depression; and headache). Adverse Reactions in the Xyrem Pediatric Clinical Trial The most common adverse reactions (≥5%) were nausea (20%), enuresis (19%), vomiting (18%), headache (17%), weight decreased (13%), decreased appetite (9%), dizziness (8%), and sleepwalking (6%). Additional information regarding safety in pediatric patients appears in the following sections: • Respiratory Depression and Sleep-Disordered Breathing [see Warnings and Precautions ( 5.4 )] • Depression and Suicidality [see Warnings and Precautions ( 5.5 )] • Other Behavioral or Psychiatric Adverse Reactions [see Warnings and Precautions ( 5.6 )] • Parasomnias [see Warnings and Precautions ( 5.7 )] The overall adverse reaction profile of Xyrem in the pediatric clinical trial was similar to that seen in the adult clinical trial program. The safety profile in pediatric patients with XYWAV is expected to be similar to that of adult patients treated with XYWAV and to that of pediatric patients treated with Xyrem. Adult Patients with Idiopathic Hypersomnia The safety of XYWAV was evaluated in a double-blind placebo-controlled randomized‑withdrawal study in patients with IH (Study 2). This study consisted of an open‑label titration period (OL OTTP) up to 14 weeks, a stable-dose period (SDP) for 2 weeks, a double‑blind, placebo‑controlled, randomized-withdrawal period (DB RWP) for 2 weeks, and an open-label extension period for 24 weeks (all study periods up to 42 weeks) [see Clinical Studies ( 14.3 )] . The study was conducted in 154 adult male and female patients ages 19 to 75 years of age with IH. The mean exposure to XYWAV during this study, including titration, the randomized withdrawal period, and the open-label extension, was 204 days. In patients who remained on treatment, adverse reactions tended to occur early and diminish over time. Adverse Reactions Leading to Treatment Discontinuation in Study 2 In Study 2, across all study periods (excluding placebo during the DB RWP) (up to 42 weeks), 17 of 154 patients (11%) reported adverse reactions that led to withdrawal from the study (anxiety, nausea, insomnia, vomiting, fatigue, feeling abnormal, fall, decreased appetite, dizziness, paresthesia, tremor, parasomnia, confusional state, hallucination visual, and irritability). The most common adverse reaction leading to discontinuation was anxiety (3.2%). The majority of adverse reactions leading to discontinuation began during the first few weeks of treatment. Commonly Observed Adverse Reactions The most common adverse reactions in Study 2 (incidence ≥5% of XYWAV‑treated patients) in addition to those observed in Study 1 as most common were insomnia, dry mouth, fatigue, somnolence, and tremor. The safety profile observed in Study 2 was similar to that of Study 1. Adverse reactions occurring in ≥2% of patients treated with XYWAV in the open-label titration and stable dose periods in Study 2 are shown in Table 5: Table 5: Adverse Reactions Occurring in ≥2% of Patients Treated with XYWAV in the Open-Label Titration and Stable Dose Periods in Study 2 * includes anxiety, nervousness, and panic attack † includes middle insomnia, initial insomnia, insomnia, and terminal insomnia ‡ includes hyperhidrosis and night sweats § includes fatigue and asthenia ¶ includes somnolence and sedation # includes confusional arousal, sleep paralysis, nightmare, sleep talking, somnambulism, and hypnopompic hallucination ♠ includes balance disorder and ataxia Adverse Reaction Open-Label Titration Period + Stable Dose Period (up to 16 weeks) (N=154) % Nausea 21 Headache 16 Anxiety * 12 Dizziness 12 Insomnia † 9 Hyperhidrosis ‡ 8 Decreased appetite 8 Vomiting 7 Dry mouth 6 Diarrhea 5 Fatigue § 5 Somnolence ¶ 5 Tremor 5 Parasomnia # 5 Balance disorder ♠ 3 Muscle spasms 3 Fall 3 Paresthesia 3 Snoring 3 Weight decreased 3 Bruxism 3 Confusional state 3 Depressed mood 3 Feeling drunk 3 Irritability 3 Additional Adverse Reactions Adverse reactions observed in clinical studies with Xyrem (≥2%), but not observed in Study 1 or Study 2 at a frequency of higher than 2%, and which may be relevant for XYWAV: Pain, pain in extremity, cataplexy, disturbance in attention, sleep paralysis, and disorientation. 6.2 Postmarketing Experience The following adverse reactions have been identified during postapproval use of sodium oxybate. 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: Arthralgia, fall*, fluid retention, hangover, hypersensitivity, hypertension, memory impairment, nocturia, and vision blurred. * The sudden onset of sleep in patients taking sodium oxybate, including in a standing position or while rising from bed, has led to falls complicated by injuries, in some cases requiring hospitalization.
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5 WARNINGS AND PRECAUTIONS • CNS depression: Use caution when considering the concurrent use of XYWAV with other CNS depressants ( 5.1 ). • Caution patients against hazardous activities requiring complete mental alertness or motor coordination within the first 6 hours of dosing or after first initiating treatment until certain that XYWAV does not affect them adversely ( 5.1 ). • Depression and suicidality: Monitor patients for emergent or increased depression and suicidality ( 5.5 ). • Confusion/Anxiety: Monitor for impaired motor/cognitive function ( 5.6 ). • Parasomnias: Evaluate episodes of sleepwalking ( 5.7 ). 5.1 Central Nervous System Depression XYWAV is a central nervous system (CNS) depressant. Clinically significant respiratory depression and obtundation has occurred in adult patients taking sodium oxybate (same active moiety as XYWAV) at recommended doses in clinical trials and may occur in patients treated with XYWAV at recommended doses. XYWAV is contraindicated in combination with alcohol and sedative hypnotics. The concurrent use of XYWAV with other CNS depressants, including but not limited to opioid analgesics, benzodiazepines, sedating antidepressants or antipsychotics, sedating anti-epileptic drugs, general anesthetics, muscle relaxants, and/or illicit CNS depressants, may increase the risk of respiratory depression, hypotension, profound sedation, syncope, and death. If use of these CNS depressants in combination with XYWAV is required, dose reduction or discontinuation of one or more CNS depressants (including XYWAV) should be considered. In addition, if short-term use of an opioid (e.g., post- or perioperative) is required, interruption of treatment with XYWAV should be considered. Healthcare providers should caution patients about operating hazardous machinery, including automobiles or airplanes, until they are reasonably certain that XYWAV does not affect them adversely (e.g., impair judgment, thinking, or motor skills). Patients should not engage in hazardous occupations or activities requiring complete mental alertness or motor coordination, such as operating machinery or a motor vehicle or flying an airplane, for at least 6 hours after taking XYWAV. Patients should be queried about CNS depression‐related events upon initiation of XYWAV therapy and periodically thereafter. XYWAV is available only through a restricted program under a REMS [see Warnings and Precautions ( 5.3 )] . 5.2 Abuse and Misuse XYWAV is a Schedule III controlled substance. The active moiety of XYWAV is oxybate, also known as gamma-hydroxybutyrate (GHB), a Schedule I controlled substance. Abuse of illicit GHB, either alone or in combination with other CNS depressants, is associated with CNS adverse reactions, including seizure, respiratory depression, decreases in the level of consciousness, coma, and death. The rapid onset of sedation, coupled with the amnestic features of GHB, particularly when combined with alcohol, has proven to be dangerous for the voluntary and involuntary user (e.g., assault victim). Because illicit use and abuse of GHB have been reported, healthcare providers should carefully evaluate patients for a history of drug abuse and follow them closely, particularly for signs of misuse or abuse of GHB (including but not limited to increase in size or frequency of dosing, drug-seeking behavior, feigned cataplexy) [see Drug Abuse and Dependence ( 9.2 )] . If abuse is suspected, treatment with XYWAV should be discontinued . XYWAV is available only through a restricted program under a REMS [see Warnings and Precautions ( 5.3 )] . 5.3 XYWAV and XYREM REMS XYWAV is available only through a restricted distribution program called the XYWAV and XYREM REMS because of the risks of central nervous system depression, and abuse and misuse [see Warnings and Precautions ( 5.1 , 5.2 )]. Notable requirements of the XYWAV and XYREM REMS include the following: • Healthcare Providers who prescribe XYWAV are specially certified • XYWAV will be dispensed only by the central pharmacy that is specially certified • XYWAV will be dispensed and shipped only to patients who are enrolled in the XYWAV and XYREM REMS with documentation of safe use. Further information is available at www.XYWAVXYREMREMS.com or 1-866-997-3688. 5.4 Respiratory Depression and Sleep-Disordered Breathing XYWAV may impair respiratory drive, especially in patients with compromised respiratory function. In overdoses of oxybate and with illicit use of GHB, life-threatening respiratory depression has been reported [see Overdosage ( 10 )]. Increased apnea and reduced oxygenation may occur with XYWAV administration in adult and pediatric patients. A significant increase in the number of central apneas and clinically significant oxygen desaturation may occur in patients with obstructive sleep apnea treated with XYWAV. In a study assessing the respiratory-depressant effects of Xyrem (same active moiety as XYWAV) at doses up to 9 g per night in 21 adult patients with narcolepsy, no dose-related changes in oxygen saturation were demonstrated in the group as a whole. One of the four patients with preexisting moderate-to-severe sleep apnea had significant worsening of the apnea/hypopnea index during treatment. In a study assessing the effects of Xyrem 9 g per night in 50 adult patients with obstructive sleep apnea, Xyrem did not increase the severity of sleep‑disordered breathing and did not adversely affect the average duration and severity of oxygen desaturation overall. However, there was a significant increase in the number of central apneas in patients taking Xyrem, and clinically significant oxygen desaturation (≤55%) was measured in three patients (6%) after Xyrem administration, with one patient withdrawing from the study and two continuing after single brief instances of desaturation. During polysomnographic evaluation (PSG), central sleep apnea and oxygen desaturation were observed in pediatric patients with narcolepsy treated with Xyrem. Prescribers should be aware that increased central apneas and clinically relevant oxygen desaturation events have been observed with sodium oxybate administration in adult and pediatric patients. In clinical trials of Xyrem in 128 adult patients with narcolepsy, two patients had profound CNS depression, which resolved after supportive respiratory intervention. Two other patients discontinued sodium oxybate because of severe difficulty breathing and an increase in obstructive sleep apnea. In two controlled trials assessing PSG measures in adult patients with narcolepsy, 40 of 477 patients were included with a baseline apnea/hypopnea index of 16 to 67 events per hour, indicative of mild to severe sleep-disordered breathing. None of the 40 patients had a clinically significant worsening of respiratory function, as measured by apnea/hypopnea index and pulse oximetry at doses of 4.5 g to 9 g per night. Prescribers should be aware that sleep-related breathing disorders tend to be more prevalent in obese patients, in men, in postmenopausal women not on hormone replacement therapy, and among patients with narcolepsy. 5.5 Depression and Suicidality Depression, and suicidal ideation and behavior can occur in patients treated with XYWAV. In Study 1 [see Clinical Studies ( 14.1 )] , depression and depressed mood were reported in 3% and 4%, respectively, of patients treated with XYWAV. Two patients (1%) discontinued XYWAV because of depression, but in most cases, no change in XYWAV treatment was required. In Study 2 [see Clinical Studies ( 14.3 )] , depression and depressed mood were reported in 1 patient (1%) and in 5 patients (3%), respectively, of patients treated with XYWAV, all of whom continued XYWAV treatment. In clinical trials of Xyrem (same active moiety as XYWAV) in adult patients with narcolepsy (n=781), there were two suicides and two attempted suicides in patients treated with Xyrem, including three patients with a previous history of depressive psychiatric disorder. Of the two suicides, one patient used Xyrem in conjunction with other drugs. Xyrem was not involved in the second suicide. Adverse reactions of depression were reported by 7% of 781 patients treated with Xyrem, with four patients (<1%) discontinuing because of depression. In most cases, no change in Xyrem treatment was required. In a clinical trial with Xyrem in pediatric patients with narcolepsy (n=104), one patient experienced suicidal ideation and two patients reported depression while taking Xyrem. The emergence of depression in patients treated with XYWAV requires careful and immediate evaluation. Patients with a previous history of a depressive illness and/or suicide attempt should be monitored carefully for the emergence of depressive symptoms while taking XYWAV. 5.6 Other Behavioral or Psychiatric Adverse Reactions Other behavioral and psychiatric adverse reactions can occur in patients taking XYWAV. In Study 1, confusion occurred in 1% of patients treated with XYWAV and anxiety occurred in 5% of patients treated with XYWAV. One patient experienced visual hallucinations and confusion after ingesting approximately 9 grams of XYWAV. In Study 2, confusion occurred in 3% of patients treated with XYWAV, and anxiety occurred in 16% patients treated with XYWAV. One patient experienced visual hallucinations which led to discontinuation of XYWAV. Other neuropsychiatric reactions reported in clinical trials of Xyrem (same active moiety as XYWAV) in adult patients with narcolepsy and in the postmarketing setting included hallucinations, paranoia, psychosis, aggression, and agitation. In a pediatric clinical trial with Xyrem in patients with narcolepsy, neuropsychiatric reactions, including acute psychosis, confusion, and anxiety, were reported while taking Xyrem. The emergence or increase in the occurrence of behavioral or psychiatric events in patients taking XYWAV should be carefully monitored. 5.7 Parasomnias Parasomnias can occur in patients taking XYWAV. In Study 1, parasomnias, including sleepwalking, were reported in 6% of patients treated with XYWAV. In Study 2, parasomnias, including sleepwalking, were reported in 5% of patients treated with XYWAV. In a clinical trial of Xyrem (same active moiety as XYWAV) in adult patients with narcolepsy, five instances of sleepwalking with potential injury or significant injury were reported. Parasomnias, including sleepwalking, also have been reported in a pediatric clinical trial with sodium oxybate and in postmarketing experience with sodium oxybate. Episodes of sleepwalking should be fully evaluated and appropriate interventions considered.
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12.3 Pharmacokinetics Pharmacokinetics of GHB are nonlinear and are similar following single or repeat dosing. The pharmacokinetics of oxybate following administration of XYWAV are similar between healthy subjects and patients with narcolepsy or patients with idiopathic hypersomnia. Absorption Following oral administration of XYWAV, the average time to peak plasma concentration (T max ) was about 1.3 hours in healthy adults in the fasted state. Following oral administration of XYWAV, the plasma levels of GHB increased more than dose‑proportionally, with C max increasing approximately 2 ‐ fold and AUC increasing 2.9-fold as the dose was doubled from 2.25 g to 4.5 g. Effect of Food Administration of XYWAV immediately after a high-fat meal resulted in a mean reduction in C max of GHB by 33%, and mean reduction in systemic exposure (AUC) by 16% [see Dosage and Administration ( 2.4 )] . Distribution GHB has an apparent volume of distribution averaging 190 mL/kg to 384 mL/kg. At GHB concentrations ranging from 3 mcg/mL to 300 mcg/mL. Less than 1% is bound to plasma proteins. Elimination Metabolism Animal studies indicate that metabolism is the major elimination pathway for GHB, producing carbon dioxide and water via the tricarboxylic acid (Krebs) cycle and secondarily by beta-oxidation. The primary pathway involves a cytosolic NADP + -linked enzyme, GHB dehydrogenase, that catalyzes the conversion of GHB to succinic semialdehyde, which is then biotransformed to succinic acid by the enzyme succinic semialdehyde dehydrogenase. Succinic acid enters the Krebs cycle where it is metabolized to carbon dioxide and water. A second mitochondrial oxidoreductase enzyme, a transhydrogenase, also catalyzes the conversion to succinic semialdehyde in the presence of α-ketoglutarate. An alternate pathway of biotransformation involves β-oxidation via 3,4-dihydroxybutyrate to carbon dioxide and water. No active metabolites have been identified. Excretion The clearance of GHB is almost entirely by biotransformation to carbon dioxide, which is then eliminated by expiration. On average, less than 5% of unchanged drug appears in human urine within 6 to 8 hours after dosing. Fecal excretion is negligible. GHB has a mean terminal elimination half-life of 0.66 hours. Specific Populations Geriatric Patients There is limited experience with sodium oxybate and no experience with XYWAV in the elderly. Results from a pharmacokinetic study (n=20) in another studied population indicate that the pharmacokinetic characteristics of GHB are consistent among younger (ages 48 to 64 years) and older (ages 65 to 75 years) adults. Pediatric Patients The pharmacokinetics of XYWAV has not been directly evaluated in pediatric patients. The pharmacokinetics of sodium oxybate was evaluated in pediatric patients aged 7 to 17 years and demonstrated similar PK properties as adults. A population pharmacokinetic model was developed with sodium oxybate data from pediatric and adult patients and healthy volunteers and with XYWAV data from healthy adult volunteers. The population PK model analyses demonstrate that body weight is the major intrinsic factor affecting GHB pharmacokinetics following sodium oxybate or XYWAV dosing. Additionally, XYWAV has similar PK characteristics (more than dose proportionality) as sodium oxybate in pediatric patients, supporting the same dose regimen as sodium oxybate and 1-to-1 dose switch from sodium oxybate to XYWAV in pediatric patients. Male and Female Patients In a study of 18 female and 18 male healthy adult volunteers, no gender differences were detected in the pharmacokinetics of GHB following a single Xyrem oral dose of 4.5 g. Racial or Ethnic Groups There are insufficient data to evaluate any pharmacokinetic differences among races. Patients with Renal Impairment No pharmacokinetic study in patients with renal impairment has been conducted. Patients with Hepatic Impairment The pharmacokinetics of GHB in 16 cirrhotic patients, half without ascites (Child’s Class A) and half with ascites (Child’s Class C), were compared to the kinetics in 8 subjects with normal hepatic function after a single sodium oxybate oral dose of 25 mg/kg. AUC values were double in the cirrhotic patients, with apparent oral clearance reduced from 9.1 mL/min/kg in healthy adults to 4.5 and 4.1 mL/min/kg in Class A and Class C patients, respectively. Elimination half-life was significantly longer in Class C and Class A patients than in control patients (mean t 1/2 of 59 and 32 minutes, respectively, versus 22 minutes). The starting dose of XYWAV should be reduced in patients with hepatic impairment [see Dosage and Administration ( 2.6 ) and Use in Specific Populations ( 8.6 )]. Drug Interactions Studies Studies in vitro with pooled human liver microsomes indicate that sodium oxybate does not significantly inhibit the activities of the human isoenzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, or CYP3A up to the concentration of 3 mM (378 mcg/mL), a level considerably higher than levels achieved with recommended doses. Drug interaction studies in healthy adults (age 18 to 50 years) were conducted with sodium oxybate and divalproex sodium, diclofenac, and ibuprofen. • Divalproex sodium: Co-administration of sodium oxybate (6 g per day as two equal doses of 3 grams dosed four hours apart) with divalproex sodium (valproic acid, 1250 mg per day) increased mean systemic exposure to GHB as shown by AUC by approximately 25% (AUC ratio range of 0.8 to 1.7), while C max was comparable. Co-administration did not appear to affect the pharmacokinetics of valproic acid. A greater impairment on some tests of attention and working memory was observed with co-administration of both drugs than with either drug alone [see Drug Interactions ( 7.2 ) and Dosage and Administration ( 2.7 )]. • Diclofenac: Co-administration of sodium oxybate (6 g per day as two equal doses of 3 grams dosed four hours apart) with diclofenac (50 mg/dose twice per day) showed no significant differences in systemic exposure to GHB. Co-administration did not appear to affect the pharmacokinetics of diclofenac. • Ibuprofen: Co-administration of sodium oxybate (6 g per day as two equal doses of 3 grams dosed four hours apart) with ibuprofen (800 mg/dose four times per day also dosed four hours apart) resulted in comparable systemic exposure to GHB as shown by plasma C max and AUC values. Co-administration did not affect the pharmacokinetics of ibuprofen. Drug interaction studies in healthy adults demonstrated no pharmacokinetic interactions between sodium oxybate and protriptyline hydrochloride, zolpidem tartrate, and modafinil. Also, there were no pharmacokinetic interactions with the alcohol dehydrogenase inhibitor fomepizole. However, pharmacodynamic interactions with these drugs cannot be ruled out. Alteration of gastric pH with omeprazole produced no significant change in the pharmacokinetics of GHB. In addition, drug interaction studies in healthy adults demonstrated no pharmacokinetic or clinically significant pharmacodynamic interactions between sodium oxybate and duloxetine HCl.