Slow-Release Isosorbide-5-Mononitrate for the Treatment of Angina Pectoris: Duration of Effects

Isosorbide dinitrate (ISDN) is widely used for the treatment of angina pectoris and has been shown to prolong exercise tolerance during acute and sustained therapy [1–8]. However, ISDN is poorly bioavailable after oral intake, and a marked inter-individual variation in plasma ISDN concentrations has been reported after oral doses during both acute and chronic therapy [4]. After oral ingestion, ISDN is rapidly metabolized into 2- and 5-mononitrates, both of which are biologically active. Now commercially available in Europe, isosorbide-5-mononitrate (IS-5-MN) has a half-life of 4–6 h and is almost 100% bioavailable after oral ingestion [9]. The latter makes this compound pharmacokinetically more desirable than its parent compound ISDN. Furthermore, a slow-release formulation of IS-5-MN providing high plasma levels for up to 24 h is now available which should theoretically offer advantages by exerting antianginal effects over a prolonged period of time.