Renal failure patients were treated with linezolid (LZD) for proven or suspected infections by multiresistant Gram-positive cocci. The aim of this study is to determine if dose adjustment of LZD is needed as a function of renal impairment or not, especially that a significant component of LZD is eliminated unchanged in urine.

Inclusion Criteria:

• Healthy subjects with normal renal function (CLcr ˃80 ml/min);
• Patients with acute renal failure (RF) (30˂CLcr˂80 ml/mine)
• Patients on long term HD with an ideal body weight of >60 kg and a body mass index between 20 and 26 kg/m2
• Passed all the screening parameters
• Free of any drug exposure known to interfere with the pharmacokinetics or assay of linezolid for at least 10 days prior to the study
• Able to communicate effectively with study personnel, be literate, and able to give consent.

Exclusion Criteria:

Had a history of clinically significant organ dysfunction other than renal disease or those diseases associated with renal disease (as in case of acute RF or ESRD patients) Had physical examination or laboratory test results outside the inclusion such as; sitting systolic BP (SBP) of >140 or <100 mmHg, diastolic BP (DBP) > 90 or <60mm Hg (as in case of healthy volunteers and acute RF patients), or a pulse rate of > 95 or < 50 beats/min at screening; history of orthostatic hypotension; history of serious intolerance, allergy or sensitivity to linezolid ; history of blood dyscrasias; history of alcohol, smoking, or drug abuse; donation of blood during the 8 weeks prior to the study or plans to donate blood during or within 8 weeks of completing the study; unable to tolerate vein puncture and multiple blood samplings; any surgical/medical condition that might alter the absorption, distribution, metabolism, excretion of linezolid ; or can't follow instructions, according to the investigator's opinion.

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