This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
In describing the individual actions of drugs the statement is frequently made that they are gastro-intestinal irritants, and this is a convenient opportunity for describing the symptoms produced in health by these drugs. If the drug has a caustic action, as many gastro-intestinal irritants have, the swallowing of it will cause considerable pain in the mouth and pharynx; in a short time these parts will become severely inflamed, and consequently very much reddened, swollen and painful. The tongue will be often much enlarged. If the drug is corrosive, sloughs, generally white in color at first, with a severely inflamed area around them, will be seen; as they fall off they will leave ulcers. Owing to the pain and swelling, it will for some time be impossible to take any food, or at the best only that of a soft or fluid nature. Directly after the drug reaches the stomach, intense irritation is set up; consequently the patient feels severe abdominal pain, and there is violent retching and vomiting. As the poison passes on, it produces its severe irritant effects on the intestine, and diarrhoea sets in. Both the vomited matters and the motions often contain blood. The general symptoms are an anxious countenance, small feeble pulse, scanty urine, a low temperature, and all the symptoms of collapse. Later on, the gastro-intestinal irritation may be severe enough to set up general peritonitis, or a gastric ulcer may form, and then there may be added to the case all the symptoms of gastric ulcer and its sequelae. The inflammation of the oesophagus may lead to its contraction. At the postmortem examination, if the patient has died soon after the administration of the poison, the stomach will be very red and ecchymosed, with a swollen mucous membrane. Parts of the intestine will be in the same condition. This severe inflammation may, in many places, have led to the formation of sloughs. It must be remembered that many gastro-intestinal irritants have no action on the mouth.
5. Drugs which contract the gastric vessels. - These are the same as those which have already been enumerated as being generally astringent. They are much used, more for the intestine than the stomach, and will therefore be considered in detail presently. (See-p. 95.)
6. Drugs acting on the nerves of the stomach. - All drugs powerfully irritant to the stomach cause pain in it; those that are only slightly irritant give rise to a sensation of warmth. It is never desired to produce gastric pain'.
These drugs are the same as those which are local sedatives to other parts of the body. Those most used for the stomach are -
(1) Bismuth subcarbonate.
(2) Bismuth subnitrate.
(3) Bismuth salicylate.
(5) Hydrocyanic acid.
(6) Carbon dioxide.
They are employed in the Very many painful forms of dyspepsia.
All, except perhaps stramonium, are in frequent use.
7. Drugs acting on the movements of the stomach. - It has been observed that the movements of the stomach increase as the acidity of the contents increases. If it be that the acidity is the cause of the movements, anything which causes an increase of acidity will lead to more powerful movements. Apart from this, strychnine appears directly to stimulate the unstriped muscle of the gastric wall. Stomachics also probably aid the movements, so that our complete list will be mineral acids, nux vomica, and the stomachics.
The proper churning up of the gastric contents is so necessary, that the value in dyspepsia, of drugs which aid the gastric movements, is very great. Hence the frequency with which nux vomica enters into anti-dyspeptic acid mixtures.