Related Experiment Video
Updated: Aug 9, 2026

Multiplex Therapeutic Drug Monitoring by Isotope-dilution HPLC-MS/MS of Antibiotics in Critical Illnesses
Published on: August 30, 2018
[Methods for the measurement of drug consumption: application to antibiotics]
Agnès Sommet1, Blandine Juillard-Condat, Philippe Cestac
1Unité de Pharmacoépidémiologie, EA 3696, Service de Pharmacologie Clinique, Université Paul Sabatier, Toulouse, France.
Objective:
The aim of this article is to present and compare the different methods used to study drug consumption.
Methods:
Particular attention is given to one method, the defined daily dose (DDD), for antibiotic dispensation data in Toulouse University Hospital Centre between 2001 and 2003.
Results:
Data, expressed in units of packaging, were converted into grams of active substance and then to number of DDD. The number of hospitalization days was used to calculate the penetration index (ratio of number of DDD to the number of hospitalization days). Penetration indexes were similar for each year of study period: 60.6 for 100 patient-days in 2001, 67.7 in 2002 and 66.6 in 2003 (p = 0.37). The most prescribed class was penicillin, most often amoxicillin.
Conclusion:
Use of DDD methodology and penetration index is an accessible and simple tool for monitoring consumption of antibiotics as well as other drugs.
Related Concept Videos
Dosage Interval and Administration Route: Determination Methods
Measurement of Bioavailability: Pharmacodynamic Methods
Measurement of Bioavailability: Pharmacokinetic Methods
Drug Concentrations: Measurements
Plasma —...
Drug Accumulation During Multiple Dosing: Repetitive IV Injections
Methods for Studying Drug Absorption: In vitro
The diffusion cell method uses a two-compartment cell, including a donor compartment with the drug solution, which simulates the environment where the drug is applied, and a receptor compartment with a buffer solution, which simulates the environment...

