OBJECTIVE: To study the patterns of prescribing of abciximab, a platelet function inhibitor, in percutaneous transluminal coronary angioplasty (PTCA) centres and to identify which factors determine the level of usage per centre. METHODS: The opinion-leading cardiologists from all 13 PTCA centres in the Netherlands have co-operated in our research. The questions about the use of abciximab in 1998 concerned indications, number of PTCAs performed, number of patients treated with abciximab, the funding and possible financial restrictions on the treatment, participation in clinical trials in the past, the proportion of patients receiving stents, and opinion on the appropriate level of abciximab usage. RESULTS: The level of abciximab usage varies markedly between centres, ranging from 2% to 36% of all PTCA procedures. Three out of four abciximab prescriptions surround stenting procedures. The indications for prescribing abciximab significantly differed between centres. Many physicians use abciximab not only to prevent thrombotic complications, but also to treat acute complications when they occur during PTCA and in case of suboptimal results. Together: budget, investigatorship, size, and type of the institution are highly predictive for the level of abciximab usage (R2=0.96, p<0.001). The more patients doctors have included in clinical trials in the past, the higher the likelihood they prescribe abciximab. CONCLUSIONS: Shortly after its introduction, patterns of abciximab prescribing varied significantly between PTCA centres. Abciximab is not only administered preventively, but also during and after the procedure, even though this strategy has never been evaluated in controlled trials. Budget and involvement in clinical trials in the past were important predictors of the level of usage in each centre. This is not a desirable situation, since it indicates that the level of prescribing is not so much based on patient mix, but is largely explained by non-medical factors.