Isordil Dosage

As noted under Clinical Pharmacology, multiple-dose studies with ISDN and other nitrates have shown that maintenance of continuous 24-hour plasma levels results in refractory tolerance. Every dosing regimen for ISDN must provide a daily dose-free interval to minimize the development of this tolerance. In the case of sublingual tablets, it is probably true that one of the daily dose-free intervals must be somewhat longer than 14 hours.

As also noted under CLINICAL PHARMACOLOGY, the efficacy of daily doses after the first has never been demonstrated.

Large controlled studies with other nitrates suggest that no dosing regimen with Isordil Sublingual tablets should be expected to provide more than about 12 hours of continuous anti-anginal efficacy per day.

A patient anticipating activity likely to cause angina should take one Isordil Sublingual tablet (2.5 to 5 mg) about 15 minutes before the activity is expected to begin. Isordil Sublingual tablets may be used to abort an acute anginal episode, but its use is recommended only in patients who fail to respond to sublingual nitroglycerin.