The administration of metoclopramide with atropine A drug interaction effect on the gastro–oesophageal sphincter in man

Abstract

A zone of increased intraluminal pressure exists at the gastro-oesophageal junction in man, and is believed to act as a physiological sphincter. Contraction of this lower oesophageal sphincter (LOS), probably prevents reflux of acid gastric content. ' The mechanisms involved in maintaining gastro-oesophageal competence remain controversial. Three mechanisms, independent of the LOS have been invoked in the prevention of reflux.2 These are the pinch-cock action of the diaphragm, the flap valve effect of the angle of entry of the oesophagus into the stomach and the mucosal rosette at the gastro-oesophageal junction. These three mechanisms probably play a minor, supporting role in preventing gastric reflux compared to the mechanism which is probably of primary importance, the intrinsic LOS.Pulmonary aspiration of gastric contents, with resultant chemical pneumonitis, remains a major cause of maternal death associated with obstetric anae~thesia.~ A decrease in LOS tone follows the administration of atropine,435 a drug routinely used in obstetric anaesthetic practice. Any drug which reverses this effect of atropine might enhance patient safety and prove a useful addition to the anaesthetist's armamentarium. This paper presents the results of an investigation into the effects of a combination of atropine and metoclopramide on the LOS in normal control subjects. The methods employed are described in detail because it is intended that the results of a similar study concerning the effects of these drugs on the LOS of the parturient patient at term will be reported in the future. Subjects and methodOesophageal manometric studies were performed in three groups of healthy volunteers, aged between 18 and 55 years. All subjects gave informed consent. Any previous history of upper gastrointestinal surgery or disease precluded entry to the study. All

Is cricoid pressure necessary?

“…(26) found that, without cricoid pressure, metoclopramide significantly increased the pop‐off point during manual ventilation, while atropine significantly decreased the pop‐off point. This is also supported by previous motility studies (27–29).…”

Trial of Oral Metoclopramide on Diurnal Bruxism of Brain Injury

“…The concurrent administration of anticholinergic drugs, pramlintide, for example, is known to decrease the effectiveness of metoclopramide, and such medications were not administered in our cases [10]. There was also no administration of drugs that may interfere with the actions of levodopa, such as haloperidol, loxapine, phenothiazines, in our cases.…”

Effects of i.v. metoclopramide, atropine and their combination on gastric insufflation in children anaesthetized with sevoflurane and nitrous oxide

“…Brock‐Utne et al . administered the combination of atropine 0.6 mg and metoclopramide 10 mg in healthy volunteers, and demonstrated unaltered LOS pressure (10). Similarly, the same group of investigators showed that metoclopramide given before or after atropine antagonized the LOS pressure‐lowering effect of atropine in healthy subjects (11).…”

“…On the other hand, i.v. metoclopramide alone increases LOS tone in dogs and human adults (9,10). Thus, metoclopramide may antagonize the detrimental effect of atropine on the LOS pressure in anaesthetized children, as seen in adults (11).…”