Background/aims: Nitroderivatives are therapeutically effective in spastic disorders of the oesophagus through the generation of nitric oxide, a non-adrenergic non-cholinergic inhibitory neurotransmitter, but their use is limited by undesirable side effects and rapid appearance of drug tolerance. As nitric oxide "in vivo" is generated from L-arginine, an amino acid normally present in the diet and completely devoid of toxic effects, we administered the latter substance in patients with chest pain and oesophageal motor disorders of the spastic type to investigate if it is able to produce clinical and manometric effects similar to those manifested by nitroderivatives.
Methods: In eight patients affected by non cardiac chest pain and oesophageal motor disorders of a hypertonic-hyperkinetic type without pathologic gastro-oesophageal reflux, a solution containing L-arginine and a placebo solution were infused in random order and double blind manner during a manometric examination of the oesophagus, taking into account the spontaneous variations of oesophageal motility connected with the phases of the Migrating Motor Complex. Afterwards, in the same patients a solution containing L-arginine and a placebo solution were administered orally, in random order and double blind manner, each for a period of six weeks. The effect of each treatment on frequency and intensity of chest pain attacks and on nitroderivatives intake was recorded on a diary by the patients.
Results and conclusions: The intravenous administration of L-arginine did not show the typical inhibitory effect of nitroderivatives on lower oesophageal sphincter tone and on amplitude and duration of pressure waves, but the chronic oral intake of L-arginine significantly decreased the frequency and intensity of chest pain attacks, as well as the number of nitroderivative tablets taken for analgesic purposes, thus suggesting a possible therapeutic role of this substance in this kind of patient.