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Drug interactions between Pain-Eze Paracetamol Infant Drops Colour Free and prilocaine

Results for the following 2 drugs:
Pain-Eze Paracetamol Infant Drops Colour Free (acetaminophen)

Interactions between your drugs


acetaminophen prilocaine

Applies to: Pain-Eze Paracetamol Infant Drops Colour Free (acetaminophen) and prilocaine

Consumer information for this interaction is not currently available.

MONITOR CLOSELY: Prilocaine can cause dose-related methemoglobin formation via its ortho-toluidine metabolite. Coadministration with other agents that are also associated with methemoglobinemia including other local anesthetics (e.g., benzocaine, lidocaine), antimalarials (e.g., chloroquine, primaquine, quinine, tafenoquine), nitrates and nitrites, sulfonamides, acetaminophen, aminosalicylic acid, dapsone, dimethyl sulfoxide, flutamide, metoclopramide (primarily in infants), nitrofurantoin (primarily in infants), phenazopyridine, phenobarbital, phenytoin, and rasburicase may increase the risk. Additional risk factors include very young age, anemia, cardiac/pulmonary disease, peripheral vascular disease, shock, sepsis, acidosis, and genetic predisposition (e.g., NADH cytochrome-b5 reductase deficiency; glucose-6-phosphate dehydrogenase deficiency; hemoglobin M). The development of methemoglobinemia due to prilocaine is usually dose-related and asymptomatic in normal patients receiving recommended doses, but symptoms may occur at any dose in susceptible individuals. Neonates and infants are particularly susceptible due to a lower activity of the enzyme that reduces methemoglobin to hemoglobin. Neonatal methemoglobinemia has been reported after paracervical or pudendal block in the obstetric patient. The repeated administration of prilocaine, even in relatively small doses, can lead to clinically overt methemoglobinemia (cyanosis). Prilocaine is therefore not recommended for continuous techniques of regional anesthesia.

MANAGEMENT: Prilocaine should be used with caution in the presence of other methemoglobin-inducing drugs. Patients should be closely monitored to ensure adequate perfusion and oxygenation during treatment with prilocaine. Methemoglobin levels should be monitored and oxygen administered whenever possible. Signs and symptoms of methemoglobinemia may be delayed some hours after drug exposure. Patients or their caregivers should be advised to seek medical attention if they notice signs and symptoms of methemoglobinemia such as slate-grey cyanosis in buccal mucous membranes, lips, and nail beds; nausea; headache; dizziness; lightheadedness; lethargy; fatigue; dyspnea; tachypnea; tachycardia; anxiety; and confusion. In severe cases, patients may progress to central nervous system depression, stupor, seizures, acidosis, cardiac arrhythmias, syncope, and shock. Methemoglobinemia should be considered if central cyanosis is unresponsive to oxygen. Calculated oxygen saturation and pulse oximetry are generally not accurate in the setting of methemoglobinemia. The diagnosis can be confirmed by an elevated methemoglobin level of at least 10%. If patient does not respond to administration of oxygen, clinically significant methemoglobinemia should be treated with methylene blue 1 to 2 mg/kg by slow intravenous injection over 5 minutes.


  1. Agencia EspaƱola de Medicamentos y Productos Sanitarios Healthcare "Centro de informaciĆ³n online de medicamentos de la AEMPS - CIMA. Available from: URL:" ([2018]):
  2. Cerner Multum, Inc. "Australian Product Information." O 0
  3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  4. Canadian Pharmacists Association "e-CPS. Available from: URL:"
  5. "Product Information. Citanest Plain (prilocaine)" Astra-Zeneca Pharmaceuticals, Wilmingtoon, DE.
View all 5 references

Drug and food interactions

No results found in our database - however, this does not necessarily mean no interactions exist. Always consult with your doctor or pharmacist.

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No information available.

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Further information

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