The cytoprotective and antiulcer activities of the
antacid magaldrate (ES
Riopan) as well as its effects on gastric mucosal blood flow and mucus secretions, were determined in the rat.
Magaldrate afforded protection against gastric necrotic lesions induced by absolute
ethanol (ED50, as
magaldrate, 419 mg/kg);
gastric ulcers induced by acidified
acetylsalicylic acid (ED50 540 mg/kg), stress (cold restraint, ED50 388 mg/kg),
indometacin (ED50 281 mg/kg), and pylorus
ligation; and intestinal
ulcers induced by
cysteamine (ED50 243 mg/kg) and
indometacin (ED50 184 mg/kg). At a dose of 8 ml/kg (1728 mg/kg
magaldrate), the cytoprotective effect of
magaldrate against
ethanol was evident 1 min after
oral administration and lasted more than 8 h. The cytoprotection induced by
magaldrate was decreased by pretreatments with the depletor of endogenous
thiols,
n-ethylmaleimide, or with the
cyclooxygenase inhibitor,
indometacin.
Magaldrate did not affect gastric mucosal blood flow, but it increased gastric mucus secretion. This later effect may be
a factor responsible for the cytoprotective activity of the agent. The efficacy of
magaldrate may be due not only to its
antacid, bile sequestering, and antipeptic activities, but also to its cytoprotective activity. The present results suggest that
magaldrate could be effective in preventing gastric damage caused by alcohol and antiinflammatory drugs.