Nalmefene Hydrochloride

ZURNAI is indicated for the emergency treatment of known or suspected opioid overdose induced by natural or synthetic opioids in adults and pediatric patients aged 12 years and older, as manifested by respiratory and/or central nervous system depression. ZURNAI is intended for immediate administration as emergency therapy in settings where opioids may be present. ZURNAI is not a substitute for emergency medical care. ZURNAI is an opioid antagonist indicated for the emergency treatment of known or suspected opioid overdose induced by natural or synthetic opioids in adults and pediatric patients aged 12 years and older, as manifested by respiratory and/or central nervous system depression. ( 1 ) ZURNAI is intended for immediate administration as emergency therapy in settings where opioids may be present. ( 1 ) ZURNAI is not a substitute for emergency medical care. ( 1 )

Injection: 1.5 mg nalmefene base/0.5 mL in a prefilled, single-dose auto-injector ( 3 ) Injection: 1.5 mg/0.5 mL nalmefene (base), clear, colorless to light yellow solution in a pre-filled, single-dose auto-injector. Each ZURNAI auto-injector delivers 1.5 mg nalmefene (base) injection (0.5 mL).

ZURNAI is contraindicated in patients known to be hypersensitive to nalmefene hydrochloride or to any other ingredients in the product. Hypersensitivity to nalmefene hydrochloride or to any other ingredients in ZURNAI. ( 4 )

Risk of Recurrent Respiratory and CNS Depression : A recurrence of respiratory depression is possible, therefore, keep the patient under continued surveillance and administer repeat doses of ZURNAI using a new auto-injector with each dose while awaiting emergency medical assistance. ( 5.1 ) Risk of Limited Efficacy with Partial Agonists or Mixed Agonists/Antagonists : Reversal of respiratory depression by partial agonists or mixed agonist/antagonists such as buprenorphine and pentazocine, may be incomplete. Repeat doses may be required. ( 5.2 ) Precipitation of Severe Opioid Withdrawal : The use of ZURNAI in patients who are opioid dependent may precipitate opioid withdrawal. In neonates, opioid withdrawal may be life-threatening if not recognized and properly treated. Monitor for the development of opioid withdrawal. ( 5.3 ) Risk of Cardiovascular (CV) Effects : Abrupt postoperative reversal of opioid depression may result in adverse CV effects. These events have primarily occurred in patients who had preexisting CV disorders or received other drugs that may have similar adverse CV effects. Monitor these patients closely in an appropriate healthcare setting after use of nalmefene hydrochloride. ( 5.3 ) Risk of Opioid Overdose from Attempts to Overcome the Blockade : Attempts to overcome opioid withdrawal symptoms caused by opioid antagonists with high or repeated doses of exogenous opioids may lead to opioid intoxication and death. ( 5.4 )

5.1 Risk of Recurrent Respiratory and Central Nervous System Depression Respiratory depression in the community overdose setting may be complex and involve the effects of multiple or unknown drugs, some of which may be long-acting opioids. While the duration of action of nalmefene is as long as most opioids, a recurrence of respiratory depression is possible, even after an apparently adequate initial response to ZURNAI treatment [see Clinical Pharmacology (12.3) ]. Therefore, it is necessary to seek emergency medical assistance immediately after administration of the first dose of ZURNAI and to keep the patient under continued surveillance. A second dose may be necessary if there is recurrence of symptoms of opioid overdose. Additional supportive and/or resuscitative measures may be helpful while awaiting emergency medical assistance [see Dosage and Administration (2.2) ].

5.2 Risk of Limited Efficacy with Partial Agonists or Mixed Agonist/Antagonists Reversal of respiratory depression by partial agonists or mixed agonist/antagonists such as buprenorphine and pentazocine, may be incomplete. Repeat doses of ZURNAI may be required to antagonize buprenorphine because the latter has a long duration of action due to its slow rate of binding and subsequent slow dissociation from the opioid receptor [see Dosage and Administration (2.3) ]. Buprenorphine antagonism is characterized by a gradual onset of the reversal effects and a decreased duration of action of the normally prolonged respiratory depression.

5.3 Precipitation of Severe Opioid Withdrawal The use of ZURNAI in patients who are opioid dependent may precipitate opioid withdrawal characterized by the following signs and symptoms: body aches, diarrhea, tachycardia, fever, runny nose, sneezing, piloerection, sweating, yawning, nausea or vomiting, nervousness, restlessness or irritability, shivering or trembling, abdominal cramps, weakness, and increased blood pressure. Abrupt postoperative reversal of opioid depression after using ZURNAI may result in nausea, vomiting, sweating, tremulousness, tachycardia, hypotension, hypertension, seizures, ventricular tachycardia and fibrillation, pulmonary edema, and cardiac arrest. Death, coma, and encephalopathy have been reported as sequelae of these events. These events have primarily occurred in patients who had pre-existing cardiovascular disorders or received other drugs that may have similar adverse cardiovascular effects. After use of ZURNAI, monitor patients with pre-existing cardiac disease or patients who have received medications with potential adverse cardiovascular effects for hypotension, ventricular tachycardia or fibrillation, and pulmonary edema in an appropriate healthcare setting. It has been suggested that the pathogenesis of pulmonary edema associated with the use of nalmefene is similar to neurogenic pulmonary edema, i.e., a centrally mediated massive catecholamine response leading to a dramatic shift of blood volume into the pulmonary vascular bed resulting in increased hydrostatic pressures. ZURNAI is not indicated for use in patients less than 12 years of age. In neonates, opioid withdrawal may be life-threatening if not recognized and properly treated and may include the following signs and symptoms: convulsions, excessive crying, and hyperactive reflexes. Monitor the patient for the development of the signs and symptoms of opioid withdrawal. There may be clinical settings, particularly the postpartum period in neonates with known or suspected exposure to maternal opioid use, where it is preferable to avoid the abrupt precipitation of opioid withdrawal symptoms. In these settings, use an alternative, opioid antagonist product that can be titrated to effect and, where applicable, dosed according to weight [see Use in Specific Populations (8.4) ].

5.4 Risk of Opioid Overdose from Attempts to Overcome the Blockade ZURNAI is unlikely to produce acute withdrawal symptoms in non-opioid dependent patients. The use of ZURNAI in patients who are opioid dependent may precipitate opioid withdrawal. Attempting to overcome opioid withdrawal symptoms caused by opioid antagonists with high or repeated doses of exogenous opioids could lead to opioid intoxication and death. Inform patients of the potential consequences of trying to overcome the opioid blockade. Get emergency medical assistance as soon as possible after use of ZURNAI regardless of withdrawal symptoms.

The following serious adverse reactions are described elsewhere in the labeling: Recurrent Respiratory and Central Nervous System Depression [see Warnings and Precautions (5.1) ] Precipitation of Severe Opioid Withdrawal [see Warnings and Precautions (5.3) ] Most common adverse reactions (incidence > 5%) are feeling hot, nausea, headache, dizziness, chills, vomiting, allodynia, palpitations, tinnitus, ear discomfort, feeling abnormal, burning sensation, hot flush, and irritability. ( 6 ) To report Suspected Adverse Reactions, contact Knoa Pharma LLC at 1-888-726-7535 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trial Experience Adult Clinical Trial 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 practice. The safety of ZURNAI is supported by pharmacokinetic and pharmacodynamic studies of ZURNAI in healthy subjects in a normal state and under steady state opioid agonism. The following adverse reactions were observed. In a pharmacokinetic study (NAL1005) of 21 healthy adult volunteers exposed to one dose of ZURNAI the most common adverse reactions were: dizziness and headache. In a pharmacodynamic study (NAL1004) of 23 healthy adult volunteers exposed to one dose of ZURNAI, the most common adverse reactions were: feeling hot, chills, nausea, allodynia, and headache. Table 1: Relative Frequencies of Most Common Adverse Reactions that Occurred in Greater than 5% of Subjects in Study NAL1004 and Study NAL1005 (pooled dataset) Nalmefene Auto-Injector 1.5 mg IM System Organ Class Preferred Term Pooled NAL1004 and NAL1005 N=44 n (%) Study NAL1004 N=23 n (%) Study NAL1005 N=21 n (%) Any AR 28 (63.6) 21 (91.3) 7 (33.3) Cardiac disorders Palpitations 4 (9.1) 4 (17.4) 0 Ear and labyrinth disorders Tinnitus 4 (9.1) 4 (17.4) 0 Ear discomfort 3 (6.8) 3 (13.0) 0 Gastrointestinal disorders Nausea 8 (18.2) 6 (26.1) 2 (9.5) Vomiting 5 (11.4) 3 (13.0) 2 (9.5) General disorders and administration site conditions Feeling hot 11 (25.0) 11 (47.8) 0 Chills 6 (13.6) 6 (26.1) 0 Feeling abnormal 3 (6.8) 3 (13.0) 0 Nervous system disorders Dizziness 7 (15.9) 4 (17.4) 3 (14.3) Headache 8 (18.2) 5 (21.7) 3 (14.3) Allodynia 5 (11.4) 5 (21.7) 0 Burning sensation 3 (6.8) 3 (13.0) 0 Psychiatric disorders Irritability 3 (6.8) 3 (13.0) 0 Vascular disorders Hot flush 3 (6.8) 3 (13.0) 0 Adverse reaction information was obtained following administration of nalmefene hydrochloride injection to 152 healthy volunteers and to 1127 patients in controlled clinical trials for the treatment of opioid overdose or for postoperative opioid reversal. TABLE 2: Relative Frequencies of Common Adverse Reactions with an Incidence Greater than 1% (all patients, all clinical settings) Adverse Reaction Nalmefene N=1127 Placebo N=77 Nausea 18% 6% Vomiting 9% 4% Tachycardia 5% – Hypertension 5% – Postoperative pain 4% N/A Fever 3% – Dizziness 3% 1% Headache 1% 4% Chills 1% – Hypotension 1% – Vasodilatation 1% – Incidence less than 1% CARDIOVASCULAR: Bradycardia, arrhythmia DIGESTIVE: Diarrhea, dry mouth NERVOUS SYSTEM: Somnolence, depression, agitation, nervousness, tremor, confusion, withdrawal syndrome, myoclonus RESPIRATORY: Pharyngitis SKIN: Pruritus UROGENITAL: Urinary retention The incidence of adverse events was highest in patients who received more than the recommended dose of nalmefene hydrochloride injection.

6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of nalmefene. 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. Abrupt reversal of opioid depression using nalmefene in both postoperative and emergency department settings has resulted in nausea, vomiting, sweating, tremulousness, seizures, and cardiovascular instability including tachycardia, hypotension, hypertension, ventricular tachycardia and fibrillation, pulmonary edema, and cardiac arrest. Death, coma, and encephalopathy have been reported as sequelae of these events. These events have primarily occurred in patients who had pre-existing cardiovascular disorders or received other drugs that may have similar adverse cardiovascular effects. In persons who were physically dependent on opioids, abrupt reversal of opioid effects has precipitated an acute withdrawal syndrome. Signs and symptoms have included: body aches, fever, sweating, runny nose, sneezing, piloerection, yawning, weakness, shiver or trembling, nervousness, restlessness or irritability, diarrhea, nausea or vomiting, abdominal cramps, increased blood pressure, and tachycardia. In some patients, there may be aggressive behavior upon abrupt reversal of an opioid overdose. In the neonate, opioid withdrawal symptoms also included convulsions, excessive crying, and hyperactive reflexes.

8.1 Pregnancy Risk Summary Life-sustaining therapy for opioid overdose should not be withheld [see Clinical Considerations ] . There are no available data on nalmefene use in pregnant women to evaluate for a drug-associated risk of major birth defects or miscarriage. In animal reproduction studies, no effects on embryo-fetal development were observed in rats and rabbits treated with nalmefene [see Data ]. The 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 Disease-associated maternal and/or embryo/fetal risk An opioid overdose is a medical emergency and can be fatal for the pregnant woman and fetus if left untreated. Treatment with ZURNAI for opioid overdose should not be withheld because of potential concerns regarding the effects of ZURNAI on the fetus. Data Animal Data Reproduction studies have been performed in rats and rabbits by oral administration and in rabbits by intravenous administration of nalmefene. No effects on embryo-fetal development were observed at rat oral doses up to 1200 mg/m 2 /day and rabbit oral doses up to 2400 mg/m 2 /day, and intravenous dose up to 96 mg/m 2 /day, which is 52 times the human dose of 3.0 mg (two ZURNAI administrations) based on body surface area comparison. The treatment in rats did not affect offspring survival.

8.2 Lactation Risk Summary There are no data on the presence of nalmefene and its metabolites in human milk, the effects of nalmefene on the breastfed child, or the effects on milk production. Nalmefene and its metabolites are present in rat milk [ see Data ] . When a drug is present in animal milk, it is likely that the drug will be present in human milk. Data Nalmefene and its metabolites were secreted into rat milk, reaching concentrations approximately three times those in plasma at one hour and decreasing to about half the corresponding plasma concentrations by 24 hours following bolus administration. The concentration of nalmefene in animal milk does not necessarily predict the concentration of drug in human milk.

8.4 Pediatric Use The safety and effectiveness of ZURNAI for the emergency treatment of known or suspected opioid overdose, as manifested by respiratory and/or central nervous system depression, have been established in pediatric patients aged 12 years and older. Use for this indication in this age group is supported by adult studies and pharmacokinetic simulation [see Clinical Pharmacology (12.3) ]. There have been no studies conducted to evaluate the use of ZURNAI in pediatric patients. The safety and effectiveness of ZURNAI for the emergency treatment of known or suspected opioid overdose, as manifested by respiratory and/or central nervous system depression, have not been established in pediatric patients younger than 12 years of age.

8.5 Geriatric Use Clinical studies of nalmefene hydrochloride injection did not include sufficient number of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. Geriatric patients have a greater frequency of decreased hepatic, renal, or cardiac function, or other drug therapy. Therefore, the systemic exposure of nalmefene can be higher in these patients.

8.6 Hepatic Impairment Hepatic impairment substantially reduces the clearance of nalmefene [see Clinical Pharmacology (12.3) ] . For single episodes of opioid antagonism, adjustment of ZURNAI dosage is not required.

8.7 Renal Impairment Renal impairment substantially reduces the clearance of nalmefene [see Clinical Pharmacology (12.3) ] . For single episodes of opioid antagonisms, adjustment of ZURNAI dosage is not required.

ZURNAI is an antagonist at opioid receptors.