The Nelson Prescribing Project. A programmed intervention in general practice in New Zealand.

We have defined the effect and acceptability of a locally developed general practice programme for the modification of prescribing. This voluntary programme consisted of prescription analysis and feedback, followed by visits from a pharmacist, a therapeutic bulletin on benzodiazepine prescribing, and use of a locally compiled preferred medicines list. A 3-month prescription sample from 26 general practitioners (GPs) fulfilling a stable practice definition was used to compare prescribing pre-project and mid-project. For 20 out of 26 GPs, prescribing of medicines on the preferred medicines list had increased significantly 8 months after the intervention programme had been introduced. Total prescription numbers and total medicines expenditure decreased by 8.3 and 4.9%, respectively, from 1988 to 1989. The decrease in benzodiazepine prescribing was marked (mean -22.2%, range -50.3 to +4%). The cooperative multimodel approach was highly successful in modifying prescribing in general practice.

The Nelson general practice prescribing project. Part I: A pilot audit of the regional prescribing profile.

The Nelson general practice prescribing project has been set up to develop a model for cost effective prescribing in general practice. A pilot audit of regional prescribing patterns and trends for February 1989 was conducted to test data acquisition and presentation for the project, based on 12,690 scripts. There was marked variation in medicines choice, cost and number of scripts between general practitioners. The cost of prescriptions ranged from $2.20 to $127.70, median $10.77. Cardiovascular medicines were most frequently prescribed and most costly. Extemporaneous prescribing accounted for 20% of the February inventory and was highly individually variable. Benzodiazepine prescribing was not in line with current guidelines and was high, mean 6.7% of all prescribing, indicating an urgent need for unbiased drug information. Audited prescription data allows definitions of educational and pricing strategies.

The Nelson general practice prescribing project. Part II: Prescribing reports for self audit.

A special format is described for individualised feedback of audited prescribing information to practitioners. The format has been developed for general practitioners participating in the Nelson prescribing project (part I), and has been successfully trialed in conjunction with a preferred medicines list, specifically compiled for the Nelson region. The unbiased, reliable information is seen as a practical means of regular prescribing update and modification of medicine choice, as yet unexploited.

Effect of blood sample tubes on amiodarone and desethylamiodarone concentrations.

We have investigated the change in amiodarone and desethylamiodarone concentrations in blood sampled from three different Vacutainer tubes: (a) sodium heparin, (b) gel separator (SST), and (c) no additive (plain tube). Amiodarone and desethylamiodarone concentrations were determined by a reverse-phase high pressure liquid chromatography technique in samples from 12 subjects on chronic amiodarone therapy. Amiodarone concentrations were significantly lower in plasma compared with serum from either gel separator (11.5%, p = 0.05) or no additive (13.5%, p = 0.01) tubes. Desethylamiodarone concentrations were significantly lower in plasma compared with serum from gel separator tubes (8.5%, p = 0.04) and were slightly lower compared with no additive tubes (4.4%, p = 0.41). Serum amiodarone and desethylamiodarone concentrations from either no additive or gel separator tubes yielded similar results. We conclude that significant amiodarone and desethylamiodarone concentration differences occur between serum and plasma, and that no binding of amiodarone and desethylamiodarone to the separator gel occurs.