Side Effects

NYXOID® is not a substitute for emergency medical care. Call 000 immediately before administering naloxone. Additional doses may be required until emergency medical treatment arrives. Ask your pharmacist at the time of purchase.
Ask your pharmacist - they must decide if this product is right for you



Typical opioid withdrawal syndrome is expected with naloxone which may be caused by the abrupt withdrawal of opioid in people physically dependent on them.


Commonly reported adverse events reported with NYXOID® and other naloxone formulations include:1,2


  • Very common (≥ 10%): Nausea
  • Common (≥ 1%, < 10%): Dizziness, headache, abnormally rapid heart rate, low blood pressure, high blood pressure, vomiting.


Incomplete reversal


Some opioids may stay in the body longer than the duration of the naloxone in NYXOID® nasal spray. Therefore, after an initial improvement in overdose symptoms, there may be a return of respiratory and/or CNS depression, such as the patient falling back unconscious, or slowed breathing. 


The reversal of opioid overdose depends on the type and amount of opioid which is circulating in the body. If appropriately trained, and a patient only partially responds to the administration of NYXOID® nasal spray, breathing can be mechanically assisted, i.e. using ‘rescue breathing’ or ‘mouth-to-mouth resuscitation’.1


Opioid withdrawal


Many factors, both individual and environmental, influence whether a person who uses opioid drugs, either illegal or legal, will become dependent or addicted. Over time, patients may become reliant on opioid use for pain relief, or to ‘feel normal’. This is called opioid dependence. Using NYXOID® nasal spray in patients who are opioid-dependent may bring about opioid withdrawal. Patients who are receiving opioids for the relief of chronic pain may experience pain in addition to the opioid withdrawal symptoms when naloxone is administered.1,2


Common signs and symptoms of opioid withdrawal include:1 body aches, diarrhoea, abnormally rapid heart rate, fever, runny nose, sneezing, goosebumps, sweating, yawning, nausea or vomiting, nervousness, restlessness or irritability, shivering or trembling, abdominal cramps, weakness and increased blood pressure. 


If these signs and symptoms occur, no further NYXOID® should be given. A person treated with NYXOID® nasal spray may experience irritability, and become aggressive, due to their withdrawal symptoms. Take care of your safety when giving NYXOID® nasal spray. 


Reference: 1. NYXOID®  nasal spray, Product Information, September 2018. 2. McKeage K, Lyseng-Williamson KA. Naloxone nasal spray (Nyxoid®) in opioid overdose: a profile of its use in the EU. Drug Ther Perspect 2018;34:150-156.