Drug Interactions between lidocaine / prilocaine topical and propranolol

Some of the medication in prilocaine topical is absorbed through the skin into the bloodstream and may cause interactions with other medications such as lidocaine topical. When used together, this combination may increase the risk of methemoglobinemia, a condition that can lead to oxygen deprivation in tissues and vital organs due to reduced oxygen-carrying capacity of the blood. Individuals may be more susceptible to developing methemoglobinemia during treatment with these medications if they are very young (especially neonates and infants) or have anemia, diseases of the heart or lungs, blood circulation disorders, liver cirrhosis, shock, sepsis, and certain genetic predispositions such as NADH cytochrome-b5 reductase deficiency, glucose-6-phosphate dehydrogenase deficiency, and hemoglobin M. In addition, excessive use of prilocaine topical such as application of large doses or on larger than recommended areas, as well as use on inflamed or abraded areas or broken skin, can increase absorption and result in high blood levels of the medication. Close medical supervision is necessary when medications that can cause methemoglobinemia are used together. Signs and symptoms of methemoglobinemia may be delayed by several hours after treatment with prilocaine topical. Patients (or their caregivers) should seek immediate medical attention if they develop a gray discoloration of the skin, mouth, or nail bed; nausea; headache; dizziness; lightheadedness; fatigue; shortness of breath; rapid or shallow breathing; a rapid heartbeat; palpitation; anxiety; or confusion. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Consumer information for this interaction is not currently available.

MONITOR: Some beta-blockers may increase lidocaine levels and risk of toxicity. This interaction may also apply to topical formulations of lidocaine. The proposed mechanism is inhibition of CYP450 metabolism and/or decreased cardiac output and hepatic blood flow resulting in decreased hepatic metabolism of lidocaine. In addition, beta-blockers and lidocaine may also have additive negative inotropic effects on the heart. Data have been conflicting and variable. The degree of systemic absorption of topical lidocaine may be dependent on the duration of application and the applied surface area.

MANAGEMENT: Patients receiving concurrent therapy should be monitored for drowsiness, mental status changes, bradycardia, and hypotension. Lidocaine levels should be obtained when clinically necessary. If toxicity is suspected, the lidocaine infusion should be decreased, as possible or the topical formulation of lidocaine should be discontinued.