Quality improvement project: Optimal post-void residual urine volume to guide intermittent catheterization in hospitalised older persons with acute retention of urine.

INTRODUCTION: There is no consensus on the optimal postvoid residual urine volume (PVRU) as a cut-off value prior to performing intermittent catheterisation (IMC). We did a quality improvement project to determine a reasonable PVRU for use in the hospital setting. MATERIALS AND METHODS: All patients admitted to the five geriatric medicine wards in a geriatric department over a 5- month period who developed acute retention of urine were included in the project. Patients who had hydronephrosis or were already on catheter for more than a week were excluded. Patients included were randomised to PVRU of 200 ml or 300ml. The male and female participants were randomised into separate groups. The primary outcome measures were success in weaning off IMC and the development of urinary tract infection (UTI). The secondary outcomes were the frequency of IMC required and the days needed to wean off IMC successfully. RESULTS: Both the 200 ml and 300 ml groups had equal success in weaning off IMC and were equally likely to be associated with UTI. However, the 200-ml group had more IMC done within the first 3 days (3.3, SD 2.4 vs 2.4, SD 1.6, p = 0.030), but was weaned off IMC earlier (3.5, SD 1.7, vs 4.8, SD 2.3 days, p = 0.049). CONCLUSION: We conclude that PVRU of 200 ml or 300 ml are both reasonable cut-off values prior to performing IMC.

Effect of famotidine on ciprofloxacin pharmacokinetics after single intravenous and oral doses in rats.

The effect of intravenous (3.5 mg/kg) and oral (5 mg/kg) famotidine on ciprofloxacin pharmacokinetics after single (i.v.) intravenous (5 mg/kg) and oral (20 mg/kg) doses were examined in the rat. Famotidine co-administration significantly increased the terminal elimination half-life of ciprofloxacin (54% and 29% following i.v. and oral administration, respectively) and tended to reduce the total body clearance by 27% and 34% following i.v. and oral routes, respectively. The area under the plasma concentration-time curve and the mean residence time in the body after i.v. and oral doses were significantly increased following famotidine co-administration. No changes in the steady-state apparent volume of distribution was observed after i.v. administration. The maximum plasma concentration and the time to peak concentration after oral dosing were also unaffected. These results suggest a possible reduction in the total clearance of ciprofloxacin, owing to inhibition of its renal tubular excretion by famotidine. Further studies are warranted to determine whether this interaction occurs in humans.

Physical and chemical compatibility of intravenous ciprofloxacin with other drugs.

OBJECTIVE: To determine the physical and chemical compatibilities of ciprofloxacin lactate infusion with other commonly used intravenously administered drugs. DESIGN: Ciprofloxacin lactate injection in a commercially available concentration of 2 mg/mL was mixed with 15 intravenous drugs during simulated Y-site injection. Ciprofloxacin was mixed with usually employed concentrations of other drugs in a 1:1 ratio and examined physically by visual inspection and chemically by HPLC analysis. Adsorption of ciprofloxacin to intravenous administration sets with or without inline filters was also studied. SETTING: The study was carried out at ambient temperature (25 degrees C) under fluorescent lighting except for vitamin B complex, which was protected from light. All samples were prepared in a laminar airflow hood. MAIN OUTCOME MEASURES: Physical incompatibility was determined by visual inspection against a black-and-white background, and chemical incompatibility was measured by a stability-indicating HPLC assay for ciprofloxacin. Concentrations determined at time zero (before mixing) were defined as 100 percent. Values estimated for each sample at subsequent time points were calculated as percentages of the initial concentration. Recovery below 90 percent of the initial concentration is defined as significant loss. RESULTS: Of the 15 drugs studied, only heparin, furosemide, and teicoplanin were found to be incompatible with ciprofloxacin. Adsorption of ciprofloxacin to administration sets with and without inline filters was minimal. Metronidazole was also found to decrease to 90 percent of its initial concentration immediately upon mixing. CONCLUSIONS: Ciprofloxacin ready-to-infuse solution is compatible with most of the drugs studied except heparin, furosemide, teicoplanin, and, perhaps, metronidazole. Because only the stability and potency of ciprofloxacin were studied, further testing is needed to confirm if any chemical deterioration of the other drugs occurred when combined with ciprofloxacin.

A simple high-performance liquid chromatographic assay for ciprofloxacin in human serum.

A simple and selective high-performance liquid chromatographic (HPLC) method for the determination of ciprofloxacin in serum has been developed and evaluated. Serum protein was precipitated with acetonitrile. The drug and the internal standard (quinine) were evaluated from a 10 microns U-Bondapack C-18 cartridge at ambient temperature with a mobile phase consisting of acetonitrile: 0.1 M sodium dihydrogen phosphate (20:80%, v/v) adjusted to pH 3.9 with phosphoric acid, and at a flow rate of 2.5 ml/min. The effluent was monitored on a fluorescence detector using an excitation and emission wavelength of 280 and 455 nm, respectively. Each analysis required no longer than 6 min. Quantification was achieved by the measurement of the peak-height ratio and the limit of quantification for ciprofloxacin in serum is 25 ng/ml. The intraday coefficient of variation (CV) ranged from 0.4 to 5.8%, and interday CV from 4.6 to 8.8% at three different concentrations. Relative recovery ranged from 98 to 100.2% at three different concentrations. Preliminary stability tests show that ciprofloxacin is stable for at least 3 weeks in serum after freezing.

An education program that improves the psychomotor skills needed for metaproterenol inhaler use.

This is the first report assessing an education program's impact on teaching patients the psychomotor skills needed for proper use of the metaproterenol inhaler. Most patients do not use pressurized inhalers correctly. This inability could lead to suboptimal or ineffective therapy. Pharmacists provided a standardized education program to asthma patients and to those with chronic obstructive pulmonary disease for three clinic visits. Proper use of the inhaler was assessed by evaluating the patient's psychomotor performance for each visit before and after instruction. Of 19 patients, 18 demonstrated a mean improvement of 33.5 percent from preinstruction to postinstruction evaluation at the first visit (Student's t-test, p less than 0.0005). Both preinstruction and postinstruction scores demonstrated an upward trend for all three visits, the postinstruction scores always being higher than the preinstruction scores. These results indicate that our standardized education program helped improve psychomotor performance. Certain instructional aspects that need emphasis in future education programs have been identified.

Evaluation of computer-assisted self-instructional module for pharmacy continuing education.

A computer-assisted self-instructional module was developed as a method of providing continuing education to pharmacists. A prospective, nonrandomized study was conducted to investigate the effectiveness of computer-assisted instruction (CAI). Using an Apple II microcomputer and anticoagulant therapy as the content base, a series of ten case studies was written and programmed. Twenty-two staff pharmacists from a university hospital and a community hospital participated. Participants were first given a pretest, proceeded through the CAI, took the same test as a posttest, then two weeks later, took a different posttest to measure knowledge retention. The mean test scores before and immediately after the CAI were 55.8% and 80.4%. The mean test score for the two-week posttest was 74%. The mean difference was found to be highly significant for both the pretest and immediate posttest (P less than 0.0001) and the pretest and two-week posttest (P less than 0.001). The study suggested that the use of a CAI module was effective in improving, as well as maintaining, pharmacists' knowledge and that a significant portion of knowledge gained was retained after a period of two weeks. Pharmacists' evaluations of this method of continuing education were generally favorable.

Program for aminoglycoside dosage calculations using an inexpensive calculator.

A program for gentamicin and tobramycin dosage calculations using a pocket-size programmable calculator was developed and evaluated. A program based on the first-order one-compartment pharmacokinetics model for aminoglycoside dosage calculations was developed for the Sharp EL-5813 pocket-size calculator, which can store 30 programming steps and has six constant memories. (The program also can be used in other calculators with similar capabilities.) The programming steps and operational procedures for calculating loading and maintenance doses, steady-state peak and trough concentrations, the patient's elimination constant, creatinine clearance, and volume of distribution are presented. The program was evaluated by comparing predicted and observed steady-state peak and trough concentration for 24 patients receiving gentamicin therapy. There was a significant relationship between predicted and observed peak and trough plasma concentrations. The mean time required to program the calculator was less than 30 seconds, and the mean time required for each dosage and plasma-concentration calculation was approximately 2.5 minutes. The program provides a simple method to make aminoglycoside dosage recommendations and predictions of peak and trough plasma concentrations with acceptable accuracy.

Temperature dependence of the stability of tobramycin mixed with penicillins in human serum.

The stability of tobramycin in pooled human serum when combined with ampicillin, carbenicillin disodium, or penicillin G potassium after storage at 0, 23, or 37 degrees C was evaluated. Samples of pooled human serum containing tobramycin sulfate 8 micrograms/ml alone or combined with ampicillin, carbenicillin disodium, or penicillin G potassium 200 micrograms/ml were prepared and stored at 0, 23, and 37 degrees C. Single samples were removed periodically for 48 hours and frozen until assayed. Tobramycin concentration was measured by a radioenzymatic assay. A tobramycin degradation rate constant was calculated for the tobramycin control and each tobramycin-penicillin combination at each temperature; from this, the time for the tobramycin concentration to decline to 90% of the initial concentration (t90) was estimated. Stability of the penicillins was not assessed. Tobramycin degradation approximated a log-linear process in all samples for the 48-hour period. The tobramycin control sample was more stable than any of the tobramycin-penicillin solutions at each temperature. At 0 degrees C, tobramycin mixed with ampicillin was the least stable of all mixtures; at 23 and 37 degrees C, tobramycin mixed with carbenicillin was the least stable. Storing tobramycin and carbenicillin samples on ice (0 degrees C) prolonged t90 from 10 hours (23 degrees C) and 12 hours (37 degrees C) to 36 hours. The t90 values for tobramycin when mixed with ampicillin were 19, 16.5, and 20 hours at 0, 23, and 37 degrees C, respectively. Mixed with penicillin G, tobramycin t90 values at 0, 23, and 37 degrees C were 48, 44, and 16 hours, respectively. More than a 10% loss of tobramycin potency occurred in some tobramycin-penicillin solutions under the conditions of this study. Because this loss would affect the accuracy of tobramycin pharmacokinetic calculations, the authors suggested guidelines for handling tobramycin serum samples.