Narcan Side Effects Center
Medical Editor: Charles Patrick Davis, MD, PhD
Narcan (naloxone) is an opioid antagonist and is used for the complete or partial reversal of opioid depression, including respiratory depression. It is also used for diagnosis of suspected or known acute opioid overdose and also for blood pressure support in septic shock. It is available as a generic termed naloxone. Common side effects of Narcan are flushing, dizziness, tiredness, and weakness.
Narcan is available as a sterile solution for intravenous, intramuscular, and subcutaneous administration in three strengths: 0.02, 0.4 and 1 mg of naloxone hydrochloride per mL in sterile solution; the 0.4 and 1 mg doses are also available in multidose vials. Use in neonates and other pediatric patients is based on weight (usually 0.01 mg per Kg) and may be adjusted; a pediatric consultant may help manages such patients. Opioid withdrawal syndrome may occur in some patients given large doses of Narcan. Severe side effects of Narcan include agitation, hypo- and hypertension, cardiac arrhythmias, dyspnea, pulmonary edema, encephalopathy, seizures, coma, and death. Studies on the use of this drug in pregnant and women who are breastfeeding have not been done.
Our Narcan Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What is Patient Information in Detail?
Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.
Narcan in Detail - Patient Information: Side Effects
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have a serious side effect such as:
- chest pain, fast or irregular heartbeats;
- dry cough, wheezing, feeling short of breath;
- sweating, severe nausea or vomiting;
- severe headache, agitation, anxiety, confusion, ringing in your ears;
- seizure (convulsions);
- feeling like you might pass out; or
- slow heart rate, weak pulse, fainting, slow breathing (breathing may stop).
If you are being treated for narcotic drug addiction, the expected symptoms of withdrawal would include:
- feeling nervous, restless, or irritable;
- body aches;
- dizziness, weakness;
- diarrhea, stomach pain, mild nausea;
- fever, chills, goosebumps; or
- sneezing, runny nose.
Read the entire detailed patient monograph for Narcan (Naloxone) »
What is Prescribing information?
The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.
Narcan FDA Prescribing Information: Side Effects
The following adverse events have been associated with the use of NARCAN (naloxone) in postoperative patients: hypotension, hypertension, ventricular tachycardia and fibrillation, dyspnea, pulmonary edema, and cardiac arrest. Death, coma, and encephalopathy have been reported as sequelae of these events. 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) Opioid Depression
Abrupt reversal of opioid depression may result in nausea, vomiting, sweating, tachycardia, increased blood pressure, tremulousness, seizures, ventricular tachycardia and fibrillation, pulmonary edema, and cardiac arrest which may result in death (see PRECAUTIONS).
Abrupt reversal of opioid effects in persons who are physically dependent on opioids may precipitate an acute withdrawal syndrome which may include, but is not limited to, the following signs and symptoms: body aches, fever, sweating, runny nose, sneezing, piloerection, yawning, weakness, shivering or trembling, nervousness, restlessness or irritability, diarrhea, nausea or vomiting, abdominal cramps, increased blood pressure, tachycardia. In the neonate, opioid withdrawal may also include: convulsions; excessive crying; hyperactive reflexes (see WARNINGS).
Adverse events associated with the postoperative use of NARCAN (naloxone) are listed by organ system and in decreasing order of frequency as follows:
Cardiac Disorders: pulmonary edema, cardiac arrest or failure, tachycardia, ventricular fibrillation, and ventricular tachycardia. Death, coma, and encephalopathy have been reported as sequelae of these events.
Gastrointestinal Disorders: vomiting, nausea
Psychiatric Disorders: agitation, hallucination, tremulousness
Respiratory Thoracic and Mediastinal Disorders: dyspnea, respiratory depression, hypoxia
Skin and Subcutaneous Tissue Disorders: nonspecific injection site reactions, sweating
Vascular Disorders: hypertension, hypotension, hot flushes or flushing.
Drug Abuse And Dependence
NARCAN (naloxone) is an opioid antagonist. Physical dependence associated with the use of NARCAN (naloxone) has not been reported. Tolerance to the opioid antagonist effect of NARCAN (naloxone) is not known to occur.
Read the entire FDA prescribing information for Narcan (Naloxone) »
Additional Narcan Information
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