Early and effective antibiotic therapy is essential in the management of infection in critical illness. The loading dose is probably the most important dose and is a function of the volume of distribution of the drug and the desired plasma concentration but independent of renal function. Antibiotics are classified in a number of ways that have implications for dosing. Doses of hydrophilic agents such as β-lactams should be increased in the early stages of sepsis as the extravascular space increases. For lipophilic agents such as macrolides, the inflammatory process is less important, although factors such as obesity will affect dosing. Classification can also be based on pharmacodynamic properties. Concentration-dependent antibiotics such as aminoglycosides should be administered by extended interval regimens, which maximize bactericidal effect, minimize nephrotoxicity and allow time between doses for the post-antibiotic effect. The critical factor for time-dependent agents, such as β-lactams, is time above the MIC. Ideally administration of these agents should be continuous, although vascular access availability can restrict infusion time to between 4 and 6 h, which is probably adequate. As well as antibiotic factors, patient factors such as hepatic and renal failure will affect dosing. Hepatic failure will affect antibiotic metabolism, although it is most important in end-stage failure. Renal failure and support will affect drug elimination. Knowledge of these factors is essential. Patient safety and prevention of unnecessary harm is a weighty consideration in critical illness. To ensure effective treatment and minimize adverse effects, therapy should be reviewed daily and adjusted in the light of changes in patient organ function and underlying pathology.

PURPOSE.To describe clinical pharmacist interventions across a range of critical care units (CCUs) throughout the United Kingdom (UK). To identify CCU medication error rate, prescription optimisation and to identify the type and impact of each intervention in the prevention of harm and improvement of patient therapy. MATERIALS AND METHODS.A prospective observational study was undertaken in 21 UK CCUs from [5][6][7][8][9][10][11][12][13][14][15][16][17][18] th Nov 2012. A data collection web portal was designed where the specialist critical care pharmacist (SCCP) reported all interventions at their site. Each intervention was classified as either: medication error, optimisation or consult. In addition, a clinical impact scale was used to code the interventions. Interventions were scored as low, moderate, high impact and life saving. The final coding was moderated by blinded independent multidisciplinary trialists. RESULTS. 20,517 prescriptions were reviewed with 3,294 interventions recorded during the weekdays. This resulted in an overall intervention rate of 16.1%: 6.8% were classified as medication errors, 8.3 % optimisations and 1.0% consults. The interventions were classified as: low impact (34.0%), moderate impact (46.7%) high impact (19.3%) and one case was life saving. Almost three-quarters of interventions were to optimise the effectiveness of and improve safety of pharmacotherapy. CONCLUSIONS. This observational study demonstrated that both medication error resolution and pharmacist led optimisation rates were substantial. Almost 1 in 6 prescriptions required an intervention from the clinical pharmacist. The error rate was slightly lower than an earlier UK prescribing error study (EQUIP). Two thirds of the interventions were of moderate to high impact. Key wordsCritical care, interventions, specialist critical care pharmacist, medication errors, optimisations, impact coding IntroductionThe critically ill patient is at risk of medicines-related adverse events [1], drug interactions and on some occasions inadequate therapy [2]. This risk can be exacerbated by the presence of organ failure or by supportive therapies such as renal replacement therapy. Consequently, interventions to reduce medication errors and optimise therapy are an essential component of patient care. These include electronic prescribing, smart infusion pumps, medicines reconciliation, clinical guidelines and services normally led by a specialist critical care pharmacist (SCCP) [3]. Improving the safety and efficacy of medication therapy in critical care patients is the cornerstone of SCCP activity. Since the first reports of clinical pharmacist interventions in critical care in the mid-1980s [4], there has been a gradual progression from those focused on financial savings in medicine use, to reducing medication errors and more recently to the optimisation of medication therapy [5]. Clinical pharmacists have been reported to improve medicines-related patient outcomes in the use of sedation [6], antimicrobial therapy [7], therapeutic drug m...