Reasons for Overprescription of Mononitrates: The Paradigm of Stable Angina Pectoris Treatment

Background: Oral nitrates, beta-blockers, and calcium channel blockers are used to treat stable angina pectoris (SAP). The 2 therapeutic subtypes of oral nitrates are mononitrates and dinitrates, with no evidence that 1 subtype is more efficacious than the other. Although practice guidelines in Great Britain and Israel recommend dinitrates as the first-line drug for SAP, in practice, many physicians in those 2 countries prescribe mononitrates. Objectives: The aim of this study was to identify factors that influence specialist physicians (family practitioners, internists, and cardiologists) in Israel when prescribing nitrates for the prevention of SAP symptoms. Methods: A group of specialists was given a self-administered questionnaire regarding their treatment of choice for a patient with SAP described in a hypothetical case vignette. End points for prescribing preferences were evidence-based information, cost, and the influence of pharmaceutical company representatives. Results: One hundred ten specialists were given the questionnaire. Eighty-nine specialists (45 men, 44 women; mean age, 50.4 years; range, 34-67 years; response rate, 80.9%) completed it (39 family practitioners, 29 internists, and 21 cardiologists). Seventy-eight respondents (87.6%) chose to prescribe nitrates for the case vignette, and among those, 54 (69.2%) chose mononitrates and 24 (30.8%) chose dinitrates (P = 0.034). The choice of mononitrates over dinitrates was mainly affected by habit (25/54 [46.3%]) and the belief that mononitrates are more effective, safer, and/or less expensive than dinitrates (21/54 [38.9%]). Drug costs for the patient significantly influenced more family practitioners than hospital specialists (P < 0.05). Conclusions: In contrast to guideline recommendations, the paradigm of SAP treatment with nitrates in this study was characterized by significantly more prescriptions for mononitrates than dinitrates. This situation contributes to the erosion of the scarce resources of the health care system in Israel. Further efforts are needed to increase physicians' awareness of quality, cost, and choices when prescribing drugs.