Effects of 3-days' intake of a sustained-release preparation of the nitric oxide donor, isosorbide dinitrate, on oesophageal motility.

Background: Nitric oxide plays an important role in gastrointestinal motility. We evaluated the effects of a sustained-release preparation of the nitric oxide donor isosorbide dinitrate on swallow-initiated oesophageal contractions and the lower oesophageal sphincter.

Methods: Twelve healthy men, aged 23-32 years, received, at 1-week intervals and under random double-blind conditions, for 3 days either 20 mg isosorbide dinitrate, 40 mg isosorbide dinitrate or placebo twice daily (b.d.). One hour after a further dose on day 4, oesophageal motility was recorded for 30 min using a multilumen catheter with a Dent sleeve straddling the lower oesophageal sphincter and side-hole openings 0, 3, 6 and 9 cm proximal to the sleeve. Contractile responses to twelve 5-mL water swallows were evaluated.

Results: Amplitude, duration, propagation velocity and onset latency of oesophageal contractions were not affected by either dosage of isosorbide dinitrate. Lower oesophageal sphincter resting pressure was significantly lower after 40 mg (15.1 mmHg +/- 1.2 S.E.M.) and 20 mg isosorbide dinitrate b.d. (15.0 +/- 1.0 mmHg) than after placebo (17.9 +/- 1.7 mmHg; P < 0.025). Headache was reported by all subjects on 40 mg isosorbide dinitrate, seven subjects on 20 mg and by one on placebo.

Conclusions: Twenty and 40 mg sustained-release isosorbide dinitrate twice daily had no effect on swallow-initiated oesophageal contractions but decreased lower oesophageal sphincter resting pressure.