The effect of oral administration of L-arginine on anal resting pressure and anodermal blood flow in healthy volunteers

BACKGROUND: Topical application of L-arginine, the precursor of nitric oxide, reduces anal resting pressure without significant side effects and may therefore be of benefit in the treatment of anal fissure. This in vivo study investigated the effect of orally administered L-arginine on anal resting pressure and anodermal blood flow in healthy volunteers. METHODS: Eight healthy volunteers took 3 sachets of Arginaid (Novartis Consumer Health, Breda, The Netherlands) containing 15 g L-arginine on a daily basis, for 7 days. At the start of the experiment (day 0) and on days 3 and 7, plasma levels of L-arginine, anal resting pressures and anodermal blood flow were determined. RESULTS: Arginine plasma levels increased from 107.0+/-8.6 micromol/l (day 0) to 283.7+/-44.0 micromol/l on day 3 (p< 0.01) and remained elevated at day 7 (157.3+/-19.6 micromol/l, p<0.05). Anodermal blood flow and anal resting pressures were similar on days 0, 3 and 7. CONCLUSIONS: Oral administration of 15 g arginine in healthy volunteers on a daily basis increased arginine plasma levels but had no influence on anodermal blood flow and anal resting pressure.