Drug interactions
Lidocaine-prilocaine + Phenazopyridine
Severity: Major
Lidocaine-prilocaine and Phenazopyridine: 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 cause methemoglobinemia, so combined use may increase the risk of reduced oxygen-carrying capacity, cyanosis and dyspnea. The risk is greater with large application areas, children, G6PD deficiency or renal impairment.
What this interaction means in plain words
Lidocaine-prilocaine and Phenazopyridine 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.
Lidocaine-prilocaine belongs to Genitourinary; Phenazopyridine belongs to Genitourinary.
Why it happens
Additive oxidant-induced methemoglobin formation from prilocaine metabolites and phenazopyridine.
What to do
Avoid the combination in high-risk patients and limit the prilocaine application area and duration. Monitor for cyanosis and check methemoglobin and oxygen saturation if symptoms appear.
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 Lidocaine-prilocaine
- Bupivacaine implant + Lidocaine-prilocaine Moderate
- Bupivacaine liposome + Lidocaine-prilocaine Moderate
- Disopyramide + Lidocaine-prilocaine Moderate
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Lidocaine-prilocaine Moderate
- Lidocaine-prilocaine + Mexiletine Moderate
- Lidocaine-prilocaine + Nirmatrelvir / ritonavir Moderate
Other interactions of Phenazopyridine
Frequently asked questions
Can I take Lidocaine-prilocaine with Phenazopyridine?
MediHelp rates the interaction as major. Lidocaine-prilocaine and Phenazopyridine 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 cause methemoglobinemia, so combined use may increase the risk of reduced oxygen-carrying capacity, cyanosis and dyspnea. The risk is greater with large application areas, children, G6PD deficiency or renal impairment.
How serious is the interaction between Lidocaine-prilocaine and Phenazopyridine?
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 in high-risk patients and limit the prilocaine application area and duration. Monitor for cyanosis and check methemoglobin and oxygen saturation if symptoms appear.
What other medicines interact with Lidocaine-prilocaine?
MediHelp also lists interactions of Lidocaine-prilocaine with, for example, Bupivacaine implant, Bupivacaine liposome, Disopyramide. The full list is on the Lidocaine-prilocaine page.
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