Xyrem Drug Information

Xyrem is indicated for the treatment of cataplexy or excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy. Xyrem is a central nervous system depressant indicated for the treatment of cataplexy or excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy.

• 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 )]
• Use in Patients Sensitive to High Sodium Intake [see Warnings and Precautions ( 5.8 )] Most common adverse reactions in adults (≥5% and at least twice the incidence with placebo) were nausea, dizziness, vomiting, somnolence, enuresis, and tremor ( 6.1 ). Most common adverse reactions in pediatric patients (≥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 Xyrem was studied in three placebo-controlled clinical trials (Trials N1, N3, and N4, described in Sections 14.1 and 14.2 ) in 611 patients with narcolepsy (398 subjects treated with Xyrem, and 213 with placebo). A total of 781 patients with narcolepsy were treated with Xyrem in controlled and uncontrolled clinical trials. Section 6.1 and Table 4 present adverse reactions from three pooled, controlled trials (N1, N3, N4) in patients with narcolepsy. Adverse Reactions Leading to Treatment Discontinuation: Of the 398 patients with narcolepsy treated with Xyrem, 10.3% of patients discontinued because of adverse reactions compared with 2.8% of patients receiving placebo. The most common adverse reaction leading to discontinuation was nausea (2.8%). The majority of adverse reactions leading to discontinuation began during the first few weeks of treatment. Commonly Observed Adverse Reactions in Controlled Clinical Trials: The most common adverse reactions (incidence ≥5% and twice the rate seen with placebo) in patients treated with Xyrem were nausea, dizziness, vomiting, somnolence, enuresis, and tremor. Adverse Reactions Occurring at an Incidence of 2% or Greater: Table 4 lists adverse reactions that occurred at a frequency of 2% or more in any treatment group for three controlled trials and were more frequent in any Xyrem treatment group than with placebo. Adverse reactions are summarized by dose at onset. Nearly all patients in these studies initiated treatment at 4.5 g per night. In patients who remained on treatment, adverse reactions tended to occur early and to diminish over time. Table 4 Adverse Reactions Occurring in ≥2% of Adult Patients and More Frequently with Xyrem than Placebo in Three Controlled Trials (N1, N3, N4) by Body System and Dose at Onset Adverse Reaction Placebo (n=213) % Xyrem 4.5g (n=185) % Xyrem 6g (n=258) % Xyrem 9g (n=178) % ANY ADVERSE REACTION 62 45 55 70 GASTROINTESTINAL DISORDERS Nausea 3 8 13 20 Vomiting 1 2 4 11 Diarrhea 2 4 3 4 Abdominal pain upper 2 3 1 2 Dry mouth 2 1 2 1 GENERAL DISORDERS AND ADMINISTRATIVE SITE CONDITIONS Pain 1 1 <1 3 Feeling drunk 1 0 <1 3 Edema peripheral 1 3 0 0 MUSCULOSKELETAL AND CONNECTIVE TISSUE DISORDERS Cataplexy 1 1 1 2 Muscle spasms 2 2 <1 2 Pain in extremity 1 3 1 1 NERVOUS SYSTEM DISORDERS Dizziness 4 9 11 15 Somnolence 4 1 3 8 Tremor 0 0 2 5 Disturbance in attention 0 1 0 4 Paresthesia 1 2 1 3 Sleep paralysis 1 0 1 3 PSYCHIATRIC DISORDERS Disorientation 1 1 2 3 Irritability 1 0 <1 3 Sleepwalking 0 0 0 3 Anxiety 1 1 1 2 RENAL AND URINARY DISORDERS Enuresis 1 3 3 7 SKIN AND SUBCUTANEOUS TISSUE DISORDERS Hyperhidrosis 0 1 1 3 Dose-Response Information In clinical trials in narcolepsy, a dose-response relationship was observed for nausea, vomiting, paresthesia, disorientation, irritability, disturbance in attention, feeling drunk, sleepwalking, and enuresis. The incidence of all these reactions was notably higher at 9 g per night. In controlled trials in narcolepsy, discontinuations of treatment due to adverse reactions were greater at higher doses of Xyrem. Pediatric Patients (7 Years of Age and Older) In the pediatric clinical trial (Trial N5), 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. 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, 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 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. 6.2 Postmarketing Experience The following adverse reactions have been identified during postapproval use of Xyrem. 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, decreased appetite, fall*, fluid retention, hangover, headache, hypersensitivity, hypertension, memory impairment, nocturia, panic attack, vision blurred, and weight decreased. * 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.

• Concomitant use with divalproex sodium: An initial reduction in Xyrem dose of at least 20% is recommended ( 2.5 , 7.2 ). 7.1 Alcohol, Sedative Hypnotics, and CNS Depressants Xyrem is contraindicated for use in combination with alcohol or sedative hypnotics. Use of other CNS depressants may potentiate the CNS-depressant effects of Xyrem [see Warnings and Precautions ( 5.1 )] . 7.2 Divalproex Sodium Concomitant use of Xyrem with divalproex sodium results in an increase in systemic exposure to GHB, which was shown to cause a greater impairment on some tests of attention and working memory in a clinical study [see Clinical Pharmacology ( 12.3 )] . An initial dose reduction of Xyrem is recommended when used concomitantly with divalproex sodium [see Dosage and Administration ( 2.5 )] . Prescribers are advised to monitor patient response closely and adjust dose accordingly if concomitant use of Xyrem and divalproex sodium is warranted.

Pregnancy Risk Summary There are no adequate data on the developmental risk associated with the use of sodium oxybate in pregnant women. Oral administration of sodium oxybate to pregnant rats (150, 350, or 1,000 mg/kg/day) or rabbits (300, 600, or 1,200 mg/kg/day) throughout organogenesis produced no clear evidence of developmental toxicity; however, oral administration to rats throughout pregnancy and lactation resulted in increased stillbirths and decreased offspring postnatal viability and growth, at a clinically relevant dose . In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown.

Clinical Considerations Labor or Delivery Xyrem has not been studied in labor or delivery. In obstetric anesthesia using an injectable formulation of sodium oxybate, newborns had stable cardiovascular and respiratory measures but were very sleepy, causing a slight decrease in Apgar scores. There was a fall in the rate of uterine contractions 20 minutes after injection.

Placental transfer is rapid and gamma-hydroxybutyrate (GHB) has been detected in newborns at delivery after intravenous administration of GHB to mothers. Subsequent effects of sodium oxybate on later growth, development, and maturation in humans are unknown. Data Animal Data Oral administration of sodium oxybate to pregnant rats (150, 350, or 1,000 mg/kg/day) or rabbits (300, 600, or 1,200 mg/kg/day) throughout organogenesis produced no clear evidence of developmental toxicity.

The highest doses tested in rats and rabbits were approximately 1 and 3 times, respectively, the maximum recommended human dose (MRHD) of 9 g per night on a body surface area (mg/m 2 ) basis. Oral administration of sodium oxybate (150, 350, or 1,000 mg/kg/day) to rats throughout pregnancy and lactation resulted in increased stillbirths and decreased offspring postnatal viability and body weight gain at the highest dose tested. The no-effect dose for pre- and post-natal developmental toxicity in rats is less than the MRHD on a mg/m 2 basis.

Pediatric Use The safety and effectiveness of Xyrem in the treatment of cataplexy or excessive daytime sleepiness in pediatric patients (7 years of age and older) with narcolepsy have been established in a double-blind, placebo-controlled, randomized-withdrawal study . In the pediatric clinical trial with Xyrem administration in patients with narcolepsy, serious adverse reactions of central sleep apnea and oxygen desaturation documented by polysomnography evaluation; depression; suicidal ideation; neuropsychiatric reactions including acute psychosis, confusion, and anxiety; and parasomnias, including sleepwalking, have been reported . Safety and effectiveness of Xyrem in pediatric patients below the age of 7 years have not been established. Juvenile Animal Toxicity Data In a study in which sodium oxybate (0, 100, 300, or 900 mg/kg/day) was orally administered to rats during the juvenile period of development (postnatal days 21 through 90), mortality was observed at the two highest doses tested. Deaths occurred during the first week of dosing and were associated with clinical signs (including decreased activity and respiratory rate) consistent with the pharmacological effects of the drug.

Reduced body weight gain in males and females and delayed sexual maturation in males were observed at the highest dose tested. The no-effect dose for adverse effects in juvenile rats is associated with plasma exposures (AUC) less than that at the maximum recommended human dose (9 g/night).

• Xyrem is contraindicated for use in:
• combination with sedative hypnotics [see Warnings and Precautions ( 5.1 )] .
• combination with alcohol [see Warnings and Precautions ( 5.1 )] .
• patients with succinic semialdehyde dehydrogenase deficiency [see Clinical Pharmacology ( 12.3 )] .
• In combination with sedative hypnotics or alcohol ( 4 )
• Succinic semialdehyde dehydrogenase deficiency ( 4 )

Human Experience Information regarding overdose with Xyrem is derived largely from reports

in the medical literature that describe symptoms and signs in individuals who have ingested GHB illicitly. In these circumstances the co-ingestion of other drugs and alcohol was common, and may have influenced the presentation and severity of clinical manifestations of overdose. In adult clinical trials two cases of overdose with Xyrem were reported.

In the first case, an estimated dose of 150 g, more than 15 times the maximum recommended dose, caused a patient to be unresponsive with brief periods of apnea and to be incontinent of urine and feces. This individual recovered without sequelae. In the second case, death was reported following a multiple drug overdose consisting of Xyrem and numerous other drugs.

Signs and Symptoms Information about signs and symptoms associated with overdosage with

Xyrem derives from reports of illicit use of GHB. Patient presentation following overdose is influenced by the dose ingested, the time since ingestion, the co-ingestion of other drugs and alcohol, and the fed or fasted state. Patients have exhibited varying degrees of depressed consciousness that may fluctuate rapidly between a confusional, agitated combative state with ataxia and coma. Emesis (even when obtunded), diaphoresis, headache, and impaired psychomotor skills have been observed.

No typical pupillary changes have been described to assist in diagnosis; pupillary reactivity to light is maintained. Blurred vision has been reported. An increasing depth of coma and acidosis have been observed at higher doses.

Myoclonus and tonic-clonic seizures have been reported. Respiration may be unaffected or compromised in rate and depth. Cheyne-Stokes respiration and apnea have been observed.

Bradycardia and hypothermia may accompany unconsciousness, as well as muscular hypotonia, but tendon reflexes remain intact.

Recommended Treatment of Overdose General symptomatic and supportive care should be instituted

immediately, and gastric decontamination may be considered if co-ingestants are suspected. Because emesis may occur in the presence of obtundation, appropriate posture (left lateral recumbent position) and protection of the airway by intubation may be warranted. Although the gag reflex may be absent in deeply comatose patients, even unconscious patients may become combative to intubation, and rapid-sequence induction (without the use of sedative) should be considered.

Vital signs and consciousness should be closely monitored. The bradycardia reported with GHB overdose has been responsive to atropine intravenous administration. No reversal of the central depressant effects of Xyrem can be expected from naloxone or flumazenil administration.

The use of hemodialysis and other forms of extracorporeal drug removal have not been studied in GHB overdose, but have been reported in cases of acidosis associated with GHB ingestions of 125 g or greater; however, due to the rapid metabolism of sodium oxybate, these measures may not be warranted.

Poison Control Center As with the management of all cases of drug

overdosage, the possibility of multiple drug ingestion should be considered. The healthcare provider is encouraged to collect urine and blood samples for routine toxicologic screening, and to consult with a regional poison control center (1-800-222-1222) for current treatment recommendations.