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  • Impact of a Pharmacist-Initiated Therapeutic Drug Monitoring Consult Service: DISCUSSION

therapeutic drug monitoring

In this study, pharmacists made appropriate gentamicin dose adjustments in response to serum concentrations of the drug more frequently than physicians (99% and 64%, respectively; p < 0.001). Other similarly designed studies have shown benefit from a pharmacist-initiated TDM consult service. Bollish and others evaluated a pharmacist-based aminoglycoside pharmacokinetic service by assessing the appropriateness of determinations of serum gentamicin concentration before and after a 6-month pilot service was implemented. Their chart review included 43 serum gentamicin determinations (for 20 patients) before and 243 determinations (for 39 patients) after implementation of the service. Before implementation of the TDM service, 6 (14%) of the serum gentamicin concentrations were assessed appropriately, whereas after implementation of the service, 231 (95%) of the results were assessed appropriately.

Anderson and others12 analyzed the appropriateness of ordering and interpretation of serum gentamicin concentrations by physicians over a 10-month period. Definite indications for obtaining serum gentamicin level determinations were present for 189 (89.2%) of 212 samples. In total, 110 (51.9%) of 212 samples were improperly drawn, and 85 (40.1%) of the 212 results were ignored (no action taken). FurtherĀ­more, only 26 (42%) of the 62 correctly drawn (and not ignored) samples for determination of serum gentamicin were acted on appropriately. In the opinion of the study’s authors, at most 42 (19.8%) of 212 serum gentamicin results were used appropriately in making patient care decisions. Flynn and others assessed the frequency and appropriateness of determination of serum gentamicin concentration over a 9-week period and found that only 10 (22%) of 45 results were used to make appropriate therapeutic decisions. levitra plus

In the chart review reported here, most of the cases required no dose adjustment (77% before and 88% after discontinuation of the TDM service). The latter finding, coupled with a lack of documentation about serum gentamicin concentrations for patients treated after discontinuation of the service, made it difficult to deterĀ­mine whether or not serum gentamicin concentrations were actually assessed. However, in this situation, it was assumed that the clinician made a conscious decision to continue with the initial dosing regimen. Furthermore, as previously mentioned, the pattern of clinicians’ inappropriate assessments after discontinuation of the TDM service was inconsistent. Therefore, the reasoning behind these patient care decisions is unknown.

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