Warnings for Zurnai
Included as part of the "PRECAUTIONS" Section
Precautions for Zurnai
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]. 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].
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]. Buprenorphine antagonism is characterized by a gradual onset of the reversal effects and a decreased duration of action of the normally prolonged respiratory depression.
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].
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.
Patient Counseling Information
Advise the patient and family members or caregivers to read the FDA-approved patient labeling (PATIENT INFORMATION and Instructions for Use).
Instruct patients and their family members or caregivers to become familiar with all information contained in the carton as soon as they receive ZURNAI.
Recognition Of Opioid Overdose
Instruct patients and their family members or caregivers about how to recognize the signs and symptoms of an opioid overdose such as the following:
- Extreme somnolence – inability to awaken a patient verbally or upon a firm sternal rub.
- Respiratory depression – this can range from slow or shallow respiration to no respiration in a patient who is unarousable.
- Other signs and symptoms that may accompany somnolence and respiratory depression include the following:
- Miosis
- Bradycardia and/or hypotension
Risk Of Recurrent Respiratory And Central Nervous System Depression
While the duration of action of nalmefene is as long as most opioids, instruct patients and their family members or caregivers that they must seek immediate emergency medical assistance after administration of the first dose of ZURNAI and keep the patient under continued surveillance even after an apparently adequate initial response to ZURNAI. A second dose may be necessary if there is recurrence of symptoms of opioid overdose [see DOSAGE AND ADMINISTRATION, WARNINGS AND PRECAUTIONS].
Limited Efficacy For/With Partial Agonists Or Mixed Agonist/Antagonists
Instruct patients and their family members or caregivers that the reversal of respiratory depression caused by partial agonists or mixed agonist/antagonists, such as buprenorphine and pentazocine, may be incomplete and may require repeated administration of ZURNAI, using a new ZURNAI auto-injector each time [see DOSAGE AND ADMINISTRATION, WARNINGS AND PRECAUTIONS].
Precipitation Of Severe Opioid Withdrawal
Instruct patients and their family members or caregivers that the use of ZURNAI in patients who are opioid dependent may precipitate opioid withdrawal [see WARNINGS AND PRECAUTIONS, ADVERSE REACTIONS].
Administration Instructions
Instruct patients and their family member or caregivers to:
- Ensure ZURNAI is readily available in locations where persons may be intentionally or accidently exposed to an opioid overdose (i.e., opioid emergencies).
- Use ZURNAI one time only. DO NOT test or prime prior to use [see DOSAGE AND ADMINISTRATION].
- Carefully read the Instructions for Use that comes with ZURNAI.
- Administer ZURNAI as quickly as possible if a person is unresponsive and an opioid overdose is suspected, even when in doubt, because prolonged respiratory depression may result in damage to the central nervous system or death. ZURNAI is not a substitute for emergency medical care [see DOSAGE AND ADMINISTRATION].
- Administer ZURNAI directly into the outer thigh. Press the needle end firmly into the injection site (through clothing, if necessary) and hold for 3 seconds [see DOSAGE AND ADMINISTRATION]. After 3 seconds, the viewing window should turn completely orange, signaling that ZURNAI has delivered the intended dose of nalmefene.
- Remove ZURNAI from the outer thigh.
- Call 911 immediately after injecting the first dose of ZURNAI.
- Move the person to the recovery position by turning them to their side. Additional supportive and/or resuscitative measures may be helpful while awaiting emergency medical assistance [see DOSAGE AND ADMINISTRATION].
- Watch the person carefully. Wait 2 to 5 minutes to see if the person wakes up.
- If the person is not responding or responds and then relapses back into respiratory depression, administer additional doses of ZURNAI every 2 to 5 minutes using a new ZURNAI auto-injector [see DOSAGE AND ADMINISTRATION].
- Remain with the person until emergency medical help arrives, even if they wake up.
- Visually inspect the nalmefene solution through the viewing window every 30 days. If the solution is discolored, cloudy, or contains solid particles, replace it with a new ZURNAI.
- Replace ZURNAI before its expiration date.
Healthcare professionals can telephone Purdue Pharma’s Medical Information Department (1- 888-726-7535) for information on this product.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment Of Fertility
Carcinogenesis
Long-term animal studies to evaluate the carcinogenic potential of nalmefene have not been completed.
Mutagenesis
Nalmefene did not have mutagenic activity in the Ames test with five bacterial strains or the mouse lymphoma assay. Clastogenic activity was not observed in the mouse micronucleus test or in the cytogenic bone marrow assay in rats. However, nalmefene did exhibit a weak but significant clastogenic activity in the human lymphocyte metaphase assay in the absence but not in the presence of exogenous metabolic activation.
Impairment Of Fertility
Oral administration of nalmefene up to 1200 mg/m2/day did not affect fertility in rats.
Use In Specific Populations
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 drugassociated 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/m2/day and rabbit oral doses up to 2400 mg/m2/day, and intravenous dose up to 96 mg/m2/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.
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.
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]. 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.
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.
Hepatic Impairment
Hepatic impairment substantially reduces the clearance of nalmefene [see CLINICAL PHARMACOLOGY]. For single episodes of opioid antagonism, adjustment of ZURNAI dosage is not required.
Renal Impairment
Renal impairment substantially reduces the clearance of nalmefene [see CLINICAL PHARMACOLOGY]. For single episodes of opioid antagonisms, adjustment of ZURNAI dosage is not required.