Parenteral ranitidine: onset and duration of action.

Pulmonary acid aspiration syndrome has been recognized as a major hazard in the practice of emergency anaesthesia (Edwards et al., 1956; Bannister and Grenvik, 1962). This risk has been associated with a gastric fluid pH of less than 2.5 units (Teaubaut, 1952). The histamine H^receptor antagonist cimetidine is likely to be effective in reducing the pulmonary complications following acid aspiration, although this has not been entirely proved (Coombs, Hooper and Colton, 1979; Dobb, Jordan and Williams, 1979). Recently a new ^-antagonist, ranitidine, has been introduced which is said to be several times more potent, on a molar basis, in inhibiting human gastric acid secretion (Simon et al., 1980; Walt et al., 1981). This study was designed to investigate the onset and duration of action of parenteral ranitidine in healthy volunteers.