Waste generation of drug product samples versus prescriptions obtained through pharmacy dispensing.

Drug samples are often packaged differently from bulk packaging and thus they may contain a disproportionate amount of waste material. Fifteen drug samples were obtained from seven pharmaceutical companies and the packaging materials were weighed after the samples were removed. The waste produced by the samples was determined for a standard amount of drug and compared with the weight of the waste produced when the same quantity of drug was dispensed through a pharmacy. The average weight of the sample package for a standard course of therapy was significantly greater (p< or =0.05) than that of the pharmacy-dispensed prescription waste weight. The former was 5+/-4.5-fold heavier than the latter. The waste generated by drug samples in the United States was determined to be 5740 metric tons/year.

Macrolide drug interactions: an update.

OBJECTIVE: To describe the current drug interaction profiles for the commonly used macrolides in the US and Europe, and to comment on the clinical impact of these interactions. DATA SOURCES: A MEDLINE search (1975-1998) was performed to identify all pertinent studies, review articles, and case reports. When appropriate information was not available in the literature, data were obtained from the product manufacturers. STUDY SELECTION: All available data were reviewed to provide an unbiased account of possible drug interactions. DATA EXTRACTION: Data for some of the interactions were not available from the literature, but were available from abstracts or company-supplied materials. Although the data were not always explicit, the best attempt was made to deliver pertinent information that clinical practitioners would need to formulate practice opinions. When more in-depth information was supplied in the form of a review or study report, a thorough explanation of pertinent methodology was supplied. DATA SYNTHESIS: Several clinically significant drug interactions have been identified since the approval of erythromycin. These interactions usually were related to the inhibition of the cytochrome P450 enzyme systems, which are responsible for the metabolism of many drugs. The decreased metabolism by the macrolides has in some instances resulted in potentially severe adverse events. The development and marketing of newer macrolides are hoped to improve the drug interaction profile associated with this class. However, this has produced variable success. Some of the newer macrolides demonstrated an interaction profile similar to that of erythromycin; others have improved profiles. The most success in avoiding drug interactions related to the inhibition of cytochrome P450 has been through the development of the azalide subclass, of which azithromycin is the first and only to be marketed. Azithromycin has not been demonstrated to inhibit the cytochrome P450 system in studies using a human liver microsome model, and to date has produced none of the classic drug interactions characteristic of the macrolides. CONCLUSIONS: Most of the available data regarding macrolide drug interactions are from studies in healthy volunteers and case reports. These data suggest that clarithromycin appears to have an interaction profile similar to that of erythromycin. Given this similarity, it is important to consider the interaction profile of clarithromycin when using erythromycin. This is especially necessary as funds for further studies of a medication available in generic form (e.g., erythromycin) are limited. Azithromycin has produced few clinically significant interactions with any agent cleared through the cytochrome P450 enzyme system. Although the available data are promising, the final test should come from studies conducted in patients who are taking potentially interacting compounds on a chronic basis.

A randomized, crossover design study of the pharmacology of extended-spectrum fluoroquinolones for pneumococcal infections.

STUDY OBJECTIVES: The objectives of this study were to characterize the single-dose and steady-state plasma pharmacokinetics of IV levofloxacin and IV alatrofloxacin, and to compare the results to pneumococcal isolate sensitivities in order to estimate the clinical efficacy of current community-acquired pneumonia treatment regimens against pneumococcal infections. DESIGN: Two-way, open-label, randomized, crossover study. PARTICIPANTS: Each of 12 healthy volunteer subjects received IV levofloxacin, 500 mg qd for 7 days, and IV alatrofloxacin, 200 mg qd for 7 days. The two regimens were separated by a 2-week washout period. MEASUREMENTS AND RESULTS: Plasma concentration profiles were collected around the first and final doses of both regimens and were assayed for their respective quinolone concentrations. When the peak concentrations for both agents were compared to standard twofold dilution minimum inhibitory concentration (MIC) values for pneumococcal isolates, it was discovered that the breakpoint MIC value at which each compound would no longer achieve a peak plasma concentration/MIC ratio of at least 12:1 was 0.5 mg/L for levofloxacin and 0.25 mg/L for alatrofloxacin. CONCLUSIONS: Based on the MIC that inhibits 90% of isolates of Streptococcus pneumoniae for both of these agents (1.0 to 2.0 mg/L for levofloxacin and 0.125 to 0.25 mg/L for trovafloxacin), our results indicate that although the once-daily regimen of alatrofloxacin appears to be appropriate for this pathogen, a more aggressive regimen may need to be investigated to optimize the clinical and microbiological effects of levofloxacin.