Drug interactions
Phenazopyridine + Prilocaine
Severity: Major
Phenazopyridine and Prilocaine: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both prilocaine and phenazopyridine can induce methemoglobinemia. Used together, the risk of clinically significant methemoglobin formation is increased, producing cyanosis and reduced oxygen delivery.
What this interaction means in plain words
Phenazopyridine and Prilocaine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Phenazopyridine belongs to Genitourinary; Prilocaine belongs to Central Nervous System.
Why it happens
Additive oxidation of hemoglobin to methemoglobin by prilocaine metabolites and phenazopyridine.
What to do
Avoid the combination where possible, especially in patients with G6PD deficiency or anemia. If used, monitor oxygen saturation and watch for cyanosis, treating with methylene blue if methemoglobinemia develops.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Prilocaine
- Bupivacaine implant + Prilocaine Major
- Nitric oxide + Prilocaine Major
- Prilocaine + Propranolol Moderate
- Prilocaine + Timolol Moderate
- Hyaluronidase + Prilocaine Minor
- Nadolol + Prilocaine Minor
Other interactions of Phenazopyridine
Frequently asked questions
Can I take Phenazopyridine with Prilocaine?
MediHelp rates the interaction as major. Phenazopyridine and Prilocaine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both prilocaine and phenazopyridine can induce methemoglobinemia. Used together, the risk of clinically significant methemoglobin formation is increased, producing cyanosis and reduced oxygen delivery.
How serious is the interaction between Phenazopyridine and Prilocaine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible, especially in patients with G6PD deficiency or anemia. If used, monitor oxygen saturation and watch for cyanosis, treating with methylene blue if methemoglobinemia develops.
What other medicines interact with Prilocaine?
MediHelp also lists interactions of Prilocaine with, for example, Bupivacaine implant, Nitric oxide, Propranolol. The full list is on the Prilocaine page.
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