Impact of a hospital-based target drug program on institutional and community prescribing behavior.

A hospital-pharmacy-based program to decrease inappropriate prescribing of triazolam is described, and the program's effect on triazolam prescribing patterns for both hospitalized and nonhospitalized patients is reported. Pharmacists developed criteria for the triazolam "target drug program" in cooperation with the pharmacy and therapeutics committee. Pharmacists contacted prescribers when bedtime triazolam doses were ordered that (1) exceeded 0.125 mg, (2) were for patients greater than or equal to 60 years of age, and (3) were not to be given immediately before a surgical or diagnostic procedure. The pharmacists recommended to the prescribers that triazolam be started at a dosage of 0.125 mg in elderly or debilitated patients and that the dosage be adjusted according to the patient's response, with a repeat dose given if appropriate. Data were collected on triazolam use in the hospital before and after the pharmacist intervention program began. Data also were collected on sales of triazolam to community pharmacies near the hospital. The number of inpatient triazolam orders meeting the criteria for intervention decreased. The percentage of inpatient interventions that resulted in a dosage change also decreased, probably because prescribers' orders for higher triazolam dosages were more likely to be appropriate after the target drug program. Community pharmacies purchased more 0.125-mg triazolam tablets and fewer tablets of greater strengths after the target drug program. Intervention by hospital pharmacists caused a change in the inpatient prescribing pattern for triazolam and appeared to cause a parallel change in the community surrounding the hospital.

Predictability of serum digoxin concentrations in clinical practice.

A study was conducted to clarify the reliability of serum digoxin concentration (SDC) predictions in the absence of concurrent quinidine administration. The effects of age, sex, congestive heart failure (CHF), and the method used to estimate creatinine clearance were investigated. Data were collected from patients who were representative of those seen in clinical practice. Patients admitted to the study were required to have not received quinidine, to have stable renal function, to have been taking digoxin for ten consecutive days--the same dose and route of administration, and to have been categorized as having or not having CHF at the time of the SDC determination. There were 44 patients who qualified for admission to the study. SDCs were predicted on the basis of four methods for estimating creatinine clearance and four methods for estimating serum concentrations. After simple linear regression analysis, one method was found to have correlation coefficients ranging from 0.72 to 0.79, regardless of the method used to estimate creatinine clearance. In addition, analysis determined that age and presence of CHF were not factors affecting the reliability of predicted SDCs. Female patients had, on the average, a greater difference between measured and predicted SDCs; however, this was not statistically significant. Thus, in the absence of concurrent quinidine administration, SDCs may be estimated as long as the limitations of the method are acknowledged. Age, CHF, and the common methods used to estimate creatinine clearance do not significantly affect the reliability of predicted SDC values.

Gentamicin nephrotoxicity: application of multivariate analysis.

A retrospective study was conducted to identify patient risk factors associated with gentamicin nephrotoxicity using multivariate analysis. Patients were evaluated for nephrotoxicity using an algorithm that considers serum creatinine, previous general experience with the drug, alternative etiologic candidates, timing of events, drug concentrations or evidence of overdosage, dechallenge, and rechallenge. There were 220 patients who met the criteria for inclusion in the study (103 men and 117 women). Variables found not to be significant discriminators between toxic and nontoxic patients included height, weight, sex, dose, estimated peak gentamicin concentration, age, and initial renal function. Variables that were found to enter into the discriminant analysis included presence of complicating factors with nephrotoxic potential, number of concurrent potentially nephrotoxic drugs, intensity index or estimated trough gentamicin concentration, and the total dose or treatment duration. Two models were developed; the probability of correctly classifying a patient as toxic was 63.5% and 65.4%, and as nontoxic was 72.1% and 68.8% for the two models, respectively. Although the discriminant models developed were statistically significant, the discrimination between toxic and nontoxic patients was not satisfactory to allow development of a generalized predictive model. Multivariate techniques were found to be essential in allowing for the differentiation of variables causing gentamicin nephrotoxicity.