Influence of prolonged recumbency on drug disposition.

The disposition of lidocaine and penicillin was studied in normal subjects before and after 7 days of total recumbency. Penicillin (1,000,000 U) and lidocaine (100 mg) were administered intravenously. Lidocaine protein binding was also followed. Total body clearance, elimination half-life, and volume of distribution were calculated. There were no statistically significant differences in these disposition parameters before and after 7 days of recumbency. The binding of lidocaine also was not changed after bed rest. We conclude that the physiologic changes that occur during prolonged bed rest do not affect distribution or elimination of lidocaine or penicillin.