title: The effect of oral cimetidine on total and unbound serum lidocaine concentrations in patients with suspected myocardial infarction.
abstract: In this study, we prospectively evaluated the effect of oral cimetidine on serum lidocaine concentrations in 6 patients with suspected myocardial infarction. Compared to baseline lidocaine levels, total lidocaine concentrations increased by 8.2 +/- 7.8% at 6 hours, 16.4 +/- 9.0% at 12 hours and 27.9 +/- 9.4% at 24 hours after two doses of oral cimetidine. Unbound lidocaine concentrations increased by 14.3 +/- 4.1% at 6 hours, and 18.3 +/- 10.3% at 24 hours after cimetidine. In patients with myocardial infarction (3), total lidocaine concentrations increased by 24.2 +/- 10.4%, whereas unbound lidocaine increased by 8.9 +/- 10.2% at 24 hours. Therefore, increases in total lidocaine concentrations after cimetidine administration were considerably less than those previously reported and empiric dosage reductions of lidocaine in patients receiving cimetidine may not be appropriate.
mesh_terms: D000284:Administration, Oral; D000368:Aged; D002927:Cimetidine / Q000494:pharmacology*; D004347:Drug Interactions; D006801:Humans; D008012:Lidocaine / Q000097:blood* / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood*; D011446:Prospective Studies; D014693:Ventricular Fibrillation / Q000517:prevention & control
chemical_list: D002927:Cimetidine; D008012:Lidocaine