Citanest Drug Interactions: What to Avoid and What to Tell Your Doctor

Citanest (prilocaine) is generally safe at dental doses, but it can interact with certain medications in ways that increase the risk of side effects — particularly the rare but serious condition of methemoglobinemia. Before any dental procedure involving local anesthesia, your dentist should know your complete medication list. Here is what matters most.

The Most Important Interaction: Methemoglobinemia-Causing Drugs

The most clinically significant drug interactions with prilocaine involve other medications that also cause methemoglobinemia. When two methemoglobin-inducing agents are combined, the risk is additive — you can reach dangerous methemoglobin levels even at lower individual doses.

Drugs that increase methemoglobinemia risk when combined with prilocaine:

• Phenazopyridine (AZO, Pyridium): Used for urinary pain relief. This is one of the most significant interactions — phenazopyridine can substantially increase methemoglobin levels when combined with prilocaine.
• Sulfonamide antibiotics (sulfamethoxazole/TMP, Bactrim): Commonly used for UTIs and other infections. Combine with caution.
• Dapsone: Used for leprosy and some skin conditions. High methemoglobin-inducing potential.
• Nitrites and nitrates (nitroglycerin, isosorbide, amyl nitrite): Used for heart conditions. Additive methemoglobin formation.
• Acetaminophen (Tylenol) at high doses: At therapeutic doses, the risk is minimal; at very high doses, acetaminophen can increase methemoglobin levels.
• Antimalarial drugs (primaquine, chloroquine): These drugs can induce methemoglobinemia, especially in G6PD-deficient patients.
• Metoclopramide (Reglan): Used for nausea and gastroparesis. Increases methemoglobinemia risk.

Interactions Specific to Citanest Forte (Epinephrine-Containing Formulation)

Citanest Forte contains epinephrine 1:200,000. The following drug interactions apply specifically to the epinephrine component:

• Monoamine oxidase inhibitors (MAOIs) — phenelzine, tranylcypromine, selegiline: MAOIs potentiate the pressor effects of epinephrine, creating serious risk of hypertensive crisis. Avoid epinephrine-containing dental anesthetics in patients on MAOIs.
• Tricyclic antidepressants (amitriptyline, nortriptyline, imipramine): TCAs increase the cardiovascular effects of catecholamines including epinephrine. Use the smallest effective dose of epinephrine and monitor closely.
• Non-selective beta-blockers (nadolol, propranolol, timolol, pindolol): Can cause paradoxical hypertension when epinephrine is given to patients on beta-blockers due to unopposed alpha-adrenergic stimulation.
• Phenothiazines and butyrophenones (chlorpromazine, haloperidol): May reduce the pressor effect of epinephrine. These antipsychotics can interact in complex ways.
• Ergot-type oxytocic drugs (ergotamine, methylergonovine): Concurrent use with vasoconstrictors including epinephrine can cause severe hypertension and peripheral vascular ischemia.

Other Notable Interactions

• Bupivacaine implants (Xarelto, Exparel): Avoid additional local anesthetic administration within 96 hours of bupivacaine implantation. Two local anesthetics together increase systemic toxicity risk.
• Neuromuscular blocking agents (succinylcholine, vecuronium): Local anesthetics can enhance the neuromuscular blocking effect of these agents. Relevant primarily in general anesthesia settings.
• Hyaluronidase: Sometimes used alongside local anesthetics to improve diffusion. It increases systemic absorption of prilocaine, potentially shortening duration and increasing systemic concentrations.

What to Tell Your Dentist Before Your Appointment

Always give your dentist a complete, up-to-date medication list. Pay special attention to disclosing:

• All prescription medications, including psychiatric and cardiac drugs
• Over-the-counter urinary pain relievers (phenazopyridine/AZO)
• Supplements and herbal products
• Any history of G6PD deficiency, blood disorders, or methemoglobinemia

See also: Citanest Side Effects: What to Expect and When to Call Your Doctor.

If you need help finding Citanest or an appropriate alternative, medfinder can help locate available options near you.