Pharmacokinetics of Vancomycin in Adult Oncology Patients Hadeel Al-Kofide MS.c; Iman Zaghloul PhD; and Lamya Al-Naim PharmD Department of Clinical Pharmacy, College of Pharmacy. King Saud University Introduction Methods Study Design: retrospective study Study Setting and Time: the data were collected in King Khalid University Hospital (KKUH) for the year 2005 Inclusion Criteria: all adult inpatients on vancomycin with the availability of necessary data as vancomycin peak levels Exclusion Criteria: patients with acute or chronic renal failure and lack of required information  A total of 260 adult inpatients admitted in KKUH for the year 2005 on vancomycin were screened for eligibility  From those patients, 31 were chosen for analysis others were excluded due to lack of necessary data as vancomycin peak levels and acute or chronic renal failure  Two groups of patients were assigned, 18 cancer & 13 non-cancer patients  Measurement of the peak & trough levels were conducted after the third dose of the initial dosing regimen & Vancomycin pharmacokinetic parameters were calculated  The data were coded & entered in to a Statistical Package for Social Sciences (SPSS)  Pharmacokinetic calculation was conducted on Excel program  Independent sample t test was done to compare values between study groups; with a statistical significance level < 0.05  Correlation between different parameters was done using Pearson correlation. Results Characteristics Cancer Group Non- Cancer Group P- valueAge43.4 ± ± Height, cm ± ± TBW, kg 66.8 ± ± IBW, kg 55.9 ± ± BSA1.7 ± ± Characteristics Cancer Group Non- Cancer Group P- value Dose mg ± ± Frequency hr 13.3 ± ± Peak mg/L 19.1 ± ± Trough mg/L 7.1 ± ± Characteristics Cancer Group Non- Cancer Group P- value Albumin, g/L 26.1 ± ± Total Protein, g/L 62.4 ± ± Serum Creatinine, umol/L 64.2 ± ± CrCl, ml/min ± ± PK parameter Cancer Group Non- Cancer Group P-value K, hrˉ¹ 0.14 ± ± t 1/2, hr 8.6 ± ± V d, L 70 ± ± Cl, ml/min ± ± Discussion Conclusions Acknowledgments We would like to thank the departments of oncology, medical records and pharmacy staff at KKUH who helped us during our investigation.  Gram-positive infections are prevalent among cancer patients, and Methicillin-resistance Staphylcoccus aureus (MRSA) account for up to 50% of S.aureus infection  Vancomycin is an integral part of the management of infections in cancer patients when MRSA is suspected due to the emergence of such resistant organism & the absence of an alternative in these patients  Studies have shown sub-therapeutic levels of vancomycin in such population. Therefore, higher dosages have been proposed to ensure optimal drug concentrations  There was about 80% increase in vancomycin clearance in patients with cancer compared to literature on general population  When comparing with our control there was a 50% increase in the clearance  Vancomycin clearance in the control Saudi group was increased by 32% when compared to published literature  Vancomycin dose required for such patients was double the usual dose (about 60 mg/kg/day)  Critical characteristics of patients with cancer such as diagnosis, & the existence of neutropenia among other clinical parameters analyzed, had no significant correlation with or effect on vancomycin disposition  Except for creatinine clearance which would be expected in a drug eliminated mainly through renal excretion.  Standard dosage regimens of vancomycin, in oncology patients, continue to be used although they may often be suboptimal owing to the greater Cl & Vd found in this target population  Cancer patients may require higher than usual dosing regimens to ensure optimal therapeutic concentrations  TDM of vancomycin is strongly recommended in this population  More care should be taken when giving vancomycin to cancer patients due to their high clearance values. Table IV: Vancomycin Pharmacokinetic Parameters Data presented as Mean ± Standard Deviation Table III: Vancomycin Regimen Data presented as Mean ± Standard Deviation Table I: Patients’ Demographic Data Data presented as Mean ± Standard Deviation Table II: Patients’ Clinical Data, Data presented as Mean ± Standard Deviation Figure I: Comparison with Literature HM, Haematological Malignancies. Cl, Clearance. CrCl, Creatinine Clearance. Vd, Volume of Distribution. TBW, Total Body Weight  The aim of the study is to evaluate the effects of certain clinical factors on the kinetics of this drug in cancer patients and to find potential predictive factors for dosage individualization. In addition, to study its kinetics in Saudi non-cancer patients to be used for comparison with previous literature. Objectives