Key result
Pretreatment with metoprolol or propranolol significantly reduced lidocaine clearance compared to lidocaine alone (0.61 and 0.47 vs 0.88 L/hr/kg, respectively).
Why the study?
Does pretreatment with metoprolol or propranolol reduce lidocaine elimination in healthy young men?
Does pretreatment with metoprolol or propranolol reduce lidocaine elimination in healthy young men?
Both metoprolol and propranolol significantly reduce lidocaine elimination, indicating a clinically relevant pharmacokinetic drug interaction.
May increase lidocaine exposure risk with beta-blockers; leaves open need for patient outcome studies.
The effects of administration of metoprolol and propranolol on lidocaine elimination were studied in six healthy young men who did not smoke. Each received three single intravenous doses of lidocaine (2.5 to 3.0 mg/kg injected over 10 min): one alone, one after 1 day pretreatment with propranolol (40 mg orally every 6 hr), and one after 1 day pretreatment with metoprolol (50 mg orally every 6 hr). Lidocaine clearance was 0.88 +/- 0.28 l X hr-1 X kg-1 before beta blockade, 0.61 +/- 0.20 l X hr-1 X kg-1 during metoprolol dosing, and 0.47 +/- 0.16 l X hr-1 X kg-1 during propranolol dosing. There was no correlation between the change in lidocaine elimination and the steady-state concentrations of metoprolol or propranolol, nor between the change in lidocaine clearance and the change in resting heart rate produced by either beta blocker. Metoprolol and propranolol reduce lidocaine elimination significantly.
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Conrad et al. (1983) studied Healthy volunteers (n=6). Metoprolol and propranolol vs. Lidocaine alone was evaluated on Lidocaine clearance. Pretreatment with metoprolol or propranolol significantly reduced lidocaine clearance compared to lidocaine alone (0.61 and 0.47 vs 0.88 L/hr/kg, respectively).
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