warnings and cautions
5. WARNINGS AND PRECAUTIONS Risk of Recurrent Respiratory and CNS Depression : Due to the duration of action of naloxone relative to the opioid, respiratory and CNS depression may recur after the first dose of naloxone. Seek emergency medical assistance immediately after the first dose, keep the patient under continued surveillance, and administer repeated doses of naloxone using a new ZIMHI, as necessary, while awaiting emergency medical assistance. ( 5.1 ) Risk of Limited Efficacy with Partial Agonists or Mixed Agonists/Antagonists : Reversal of respiratory depression caused by partial agonists or mixed agonists/antagonists such as buprenorphine and pentazocine, may be incomplete. Larger or repeat doses may be required. ( 5.2 ) Precipitation of Severe Opioid Withdrawal : Use in patients who are opioid dependent results in rapid onset of 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 pre-existing CV disorders or received other drugs that may have similar CV effects. Monitor these patients closely in an appropriate healthcare setting after use of naloxone hydrochloride. ( 5.3 ) Risk of Accidental Needlestick Injury : After use, the ZIMHI needle is exposed until the safety guard is deployed. Stress to patients the importance of familiarizing themselves with the device and its operation prior to experiencing an emergency situation, and to immediately seek medical attention should a needlestick occur. ( 5.4 ) 5.1 Risk of Recurrent Respiratory and Central Nervous System Depression The duration of action of most opioids may exceed that of ZIMHI resulting in a return of respiratory and/or central nervous system depression after an initial improvement in symptoms. Therefore, it is necessary to seek emergency medical assistance immediately after delivering the first dose of ZIMHI. Keep the patient under continued surveillance and administer additional doses of ZIMHI if the patient is not adequately responding or responds and then relapses back into respiratory depression, as necessary [ see Dosage and Administration ( 2.2 ) ]. Additional supportive and/or resuscitative measures may be helpful while awaiting emergency medical assistance. 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. Larger or repeat doses of naloxone hydrochloride 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 ) ]. 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 ZIMHI in patients who are opioid dependent results in opioid withdrawal characterized by rapid onset of severe body aches, vomiting, diarrhea, tachycardia, fever, runny nose, sneezing, piloerection, sweating, yawning, nausea, nervousness, restlessness or irritability, shivering or trembling, abdominal cramps, weakness, and increased blood pressure. 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 patients for the development of the signs and symptoms of opioid withdrawal. Abrupt postoperative reversal of opioid depression after using naloxone hydrochloride 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. Although a direct cause and effect relationship has not been established, after use of naloxone hydrochloride, 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 naloxone hydrochloride 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. 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, consider use of an alternative naloxone product which can be titrated to effect and, where applicable, dosed according to weight [ see Use in Specific Populations ( 8.4 ) ]. 5.4 Risk of A ccidental N eedlestick I njury After use, the ZIMHI needle is exposed until the safety guard is deployed. A needlestick injury could occur during use in emergency situations. In the event that an accidental needlestick occurs, medical attention should be sought. Potential exposure to blood borne pathogens including HIV, HBV, and HCV requires immediate evaluation by a medical professional. Stress to patients the importance of familiarizing themselves with the device and its operation prior to experiencing an emergency situation, so they are familiar with the safety guard and its deployment.