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Drug Dependence

NARCAN (naloxone) should be administered cautiously to persons including newborns of mothers who are known or suspected to be physically dependent on opioids. In such cases an abrupt and complete reversal of opioid effects may precipitate an acute withdrawal syndrome.

The signs and symptoms of opioid withdrawal in a patient physically dependent on opioids may include, but are not limited to, the following: 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. In the neonate, opioid withdrawal may also include: convulsions, excessive crying, and hyperactive reflexes.

Repeat Administration

The patient who has satisfactorily responded to NARCAN (naloxone) should be kept under continued surveillance and repeated doses of NARCAN (naloxone) should be administered, as necessary, since the duration of action of some opioids may exceed that of NARCAN (naloxone) .

Respiratory Depression due to Other Drugs

NARCAN (naloxone) is not effective against respiratory depression due to non-opioid drugs and in the management of acute toxicity caused by levopropoxyphene. Reversal of respiratory depression by partial agonists or mixed agonist/antagonists, such as buprenorphine and pentazocine, may be incomplete or require higher doses of naloxone. If an incomplete response occurs, respirations should be mechanically assisted as clinically indicated.



In addition to NARCAN (naloxone) , other resuscitative measures such as maintenance of a free airway, artificial ventilation, cardiac massage, and vasopressor agents should be available and employed when necessary to counteract acute opioid poisoning.

Abrupt postoperative reversal of opioid depression may result in nausea, vomiting, sweating, tremulousness, tachycardia, increased blood pressure, seizures, ventricular tachycardia and fibrillation, pulmonary edema, and cardiac arrest which may result in death. Excessive doses of NARCAN (naloxone) in postoperative patients may result in significant reversal of analgesia and may cause agitation (see PRECAUTIONS and DOSAGE AND ADMINISTRATION; Usage in Adults-Postoperative Opioid Depression)

Several instances of hypotension, hypertension, ventricular tachycardia and fibrillation, pulmonary edema, and cardiac arrest have been reported in postoperative patients. Death, coma, and encephalopathy have been reported as sequelae of these events. These have occurred in patients most of whom had pre-existing cardiovascular disorders or received other drugs which may have similar adverse cardiovascular effects. Although a direct cause and effect relationship has not been established, NARCAN (naloxone) should be used with caution in patients with pre-existing cardiac disease or patients who have received medications with potential adverse cardiovascular effects, such as hypotension, ventricular tachycardia or fibrillation, and pulmonary edema. It has been suggested that the pathogenesis of pulmonary edema associated with the use of NARCAN (naloxone) 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.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Studies in animals to assess the carcinogenic potential of NARCAN (naloxone) have not been conducted. NARCAN (naloxone) was weakly positive in the Ames mutagenicity and in the in vitro human lymphocyte chromosome aberration test but was negative in the in vitro Chinese hamster V79 cell HGPRT mutagenicity assay and in the in vivo rat bone marrow chromosome aberration study. Reproduction studies conducted in mice and rats at doses 4-times and 8-times, respectively, the dose of a 50 kg human given 10 mg/day (when based on surface area or mg/m2), demonstrated no embryotoxic or teratogenic effects due to NARCAN (naloxone) .

Use in Pregnancy

Teratogenic Effects: Pregnancy Category C: Teratology studies conducted in mice and rats at doses 4-times and 8-times, respectively, the dose of a 50 kg human given 10 mg/day (when based on surface area or mg/m2), demonstrated no embryotoxic or teratogenic effects due to NARCAN (naloxone) . There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, NARCAN (naloxone) should be used during pregnancy only if clearly needed.

Non-teratogenic Effects: Risk-benefit must be considered before NARCAN (naloxone) is administered to a pregnant woman who is known or suspected to be opioid-dependent since maternal dependence may often be accompanied by fetal dependence. Naloxone crosses the placenta, and may precipitate withdrawal in the fetus as well as in the mother. Patients with mild to moderate hypertension who receive naloxone during labor should be carefully monitored as severe hypertension may occur.

Use in Labor and Delivery

It is not known if NARCAN (naloxone) affects the duration of labor and/or delivery. However, published reports indicated that administration of naloxone during labor did not adversely affect maternal or neonatal status.

Nursing Mothers

It is not known whether NARCAN (naloxone) is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when NARCAN (naloxone) is administered to a nursing woman.

Pediatric Use

NARCAN (naloxone hydrochloride injection, USP) may be administered intravenously, intramuscularly or subcutaneously in children and neonates to reverse the effects of opiates. The American Academy of Pediatrics, however, does not endorse subcutaneous or intramuscular administration in opiate intoxication since absorption may be erratic or delayed. Although the opiate-intoxicated child responds dramatically to NARCAN (naloxone) , he/she must be carefully monitored for at least 24 hours as a relapse may occur as naloxone is metabolized.

When NARCAN (naloxone) is given to the mother shortly before delivery, the duration of its effect lasts only for the first two hours of neonatal life. It is preferable to administer NARCAN (naloxone) directly to the neonate if needed after delivery. NARCAN (naloxone) has no apparent benefit as an additional method of resuscitation in the newly born infant with intrauterine asphyxia which is not related to opioid use.

Usage in Pediatric Patients and Neonates for Septic Shock: The safety and effectiveness of NARCAN (naloxone) in the treatment of hypotension in pediatric patients and neonates with septic shock have not been established. One study of two neonates in septic shock reported a positive pressor response; however, one patient subsequently died after intractable seizures.

Geriatric Use

Clinical studies of NARCAN (naloxone) did not include sufficient numbers 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. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Renal Insufficiency/Failure

The safety and effectiveness of NARCAN (naloxone) in patients with renal insufficiency/failure have not been established in well-controlled clinical trials. Caution should be exercised when NARCAN (naloxone) is administered to this patient population

Liver Disease

The safety and effectiveness of NARCAN (naloxone) in patients with liver disease have not been established in well-controlled clinical trials. Caution should be exercised when NARCAN (naloxone) is administered to patients with liver disease.

Last reviewed on RxList: 3/20/2009
This monograph has been modified to include the generic and brand name in many instances.


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