What are the side effects of REZENOPY?

REZENOPY nasal spray may cause serious side effects, including:¹

Sudden opioid withdrawal symptoms. In someone who has been using opioids regularly, opioid withdrawal symptoms can happen suddenly after receiving REZENOPY nasal spray and may include:
- body aches
- diarrhea
- increased heart rate
- fever
- runny nose
- sneezing
- goose bumps
- sweating
- yawning
- nausea or vomiting
- nervousness
- restlessness or irritability
- shivering or trembling
- stomach cramping
- weakness
- increased blood pressure

In infants under 4 weeks old who have been receiving opioids regularly, sudden opioid withdrawal may be life-threatening if not treated the right way. Signs and symptoms include: seizures, crying more than usual, and increased reflexes.

The most common side effects of REZENOPY nasal spray include: upperstomach-area (abdominal) pain, the common cold, and changes in sense of taste.
These are not all the possible side effects of REZENOPY nasal spray.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1 800-FDA-1088.

Denise Hearden2026-07-28T17:18:02-04:00February 24, 2026|For Patients|

Important Safety Information for REZENOPY™

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REZENOPY™ (naloxone hydrochloride) Nasal Spray 10 mg is an opioid antagonist indicated for the emergency treatment of known or suspected opioid overdose, as manifested by respiratory and/or central nervous system depression in adult and pediatric patients. It is intended for immediate administration as emergency therapy in settings where opioids may be present and is not a substitute for emergency medical care.

Important Safety Information for REZENOPY™

REZENOPY™ (naloxone hydrochloride) Nasal Spray 10 mg is an opioid antagonist indicated for the emergency treatment of known or suspected opioid overdose, as manifested by respiratory and/or central nervous system depression in adult and pediatric patients. It is intended for immediate administration as emergency therapy in settings where opioids may be present and is not a substitute for emergency medical care.

Important Safety Information

Contraindications: REZENOPY™ nasal spray is contraindicated in patients known to be hypersensitive to naloxone hydrochloride or to any of the other ingredients.

Warnings and Precautions:

- Risk of Recurrent Respiratory and CNS Depression: Due to the duration of action of naloxone relative to the opioid, keep the patient under continued surveillance and administer additional doses as necessary while awaiting emergency medical assistance.

- 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.

- Precipitation of Severe Opioid Withdrawal: Use 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.

- Risk of Cardiovascular Effects: Abrupt postoperative reversal of opioid depression may result in adverse cardiovascular effects. These events have primarily occurred in patients who had pre-existing cardiovascular disorders or received other drugs that may have similar adverse cardiovascular effects. Monitor these patients closely in an appropriate healthcare setting after use of naloxone hydrochloride.

- Adverse Reactions: The following adverse reactions were observed in a REZENOPY™ nasal spray clinical study: upper abdominal pain, nasopharyngitis, and dysgeusia.

For complete product information, including Patient Information, please refer to the full Prescribing Information.

Content on this website is intended only for United States residents. Product labeling, packaging, and images are representative only. Images of healthcare providers, patients and caregivers on this site are not actual providers and patients. REZENOPY™ is a trademark of Scienture, LLC. Manufactured in the U.S.A.

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