This research targets four anti-infectives commonly prescribed in intensive care: ceftazidime, cefepime, cefotaxime and meropenem, used for severe infections For patient hospitalized in intensive care unit , there is little or no pharmacokinetic data for these four molecules.

Antibiotics, and especially beta-lactams, are among the most used drugs in the world. The good use of antibiotics and the prevention of selection of resistant strains has been a public health priority for many years. In this context, it is essential to obtain effective antibiotic concentrations at the site of infection. In order to obtain effective concentrations, ceftazidime, cefepime, cefotaxime, piperacillin and meropenem are administered in this population by continuous infusion at high dose. Although beta-lactams are mostly well tolerated, they can cause adverse effects such as severe neurological toxicities.

The critically ill patient has physiological alterations that can significantly alter the pharmacokinetics of drugs. Several studies have clearly shown that the pharmacokinetics of beta-lactams in the critically ill patient is different from those of other patients. Depending on the clinical context and the co-morbidities of the patient, sub-therapeutic or potentially toxic concentrations can be observed for the same dosage. The risk of ineffective treatment and the development of resistance remains, despite the high doses administered. In addition, this pharmacokinetic variability may be responsible for the observation of toxic concentrations and the occurrence of adverse effects in this population.

Following these arguments, therapeutic drug monitoring (TDM) of beta-lactams accompanied by personalized dosage adjustment appears to be an essential tool to optimize the management of critically ill patients. Although strongly recommended, the TDM of beta-lactams in the critically ill patient accompanied by a dosage adjustment is not currently performed systematically in all patients.

The objective of this study is to evaluate the impact of the use of a systematic therapeutic drug monitoring of beta-lactams in the critically ill treated with cefotaxime, ceftazidime, cefepime, meropenem or piperacillin, in terms of efficacy and prevention of neurotoxicity.

Inclusion Criteria:

• Adult patient (age> 18 years)
• Patient hospitalized in intensive care for a duration greater than 7 days, treated with cefotaxime, ceftazidime, cefepime, piperacillin or meropenem according to a standardized dosing regimen.

Exclusion Criteria:

• Age <18
• Pregnant woman
• Patient allergic to beta-lactams
• No written informed consent by the patient or his/her (legal) representative