V/F parameter altered in obese individuals on amoxicillin
22 Aug 2021
Volume of distribution (V/F) is the main pharmacokinetic (PK) parameter altered in obese individuals receiving amoxicillin (AMX) due to their greater body weight, reveals a recent study. This may lead to failure of antibiotic treatment if standard therapeutic regimens are administered.
The investigators performed a prospective, single-centre, open-label, clinical study on nonobese and obese individuals who received AMX 875-mg tablets. Then, they collected serial blood samples between 0 and 8 hours after administration of AMX and quantified plasma levels using liquid chromatography-tandem mass spectrometry.
In addition, noncompartmental analysis was carried out to calculate the PK parameters. Student t-test was used to compare the means of the two groups and Pearson’s correlation coefficient to analyse the association between covariates and PK.
Ten nonobese (mean age 30.6±7.12 years, body mass index 21.56±1.95 kg/m2) and 20 obese individuals (mean age 34.47±7.03 years, body mass index 33.17 ± 2.38 kg/m2) were included in the analysis. Nonobese individuals had slightly higher maximum concentration (Cmax, 12.12±4.06 vs 9.66±2.93 mg/L) and area under the curve (AUC)0-inf (34.18±12.94 vs 26.88±9.24 mg.h/L), but the differences were nonsignificant.
Moreover, the V/F parameter was significantly higher in obese than nonobese participants (44.20±17.85 vs 27.57±12.96 L). Statistically significant associations were also noted for several weight metrics with AUC, Cmax, V/F, and clearance, as well as for creatinine clearance with AUC, Cmax, and clearance.