Regarding the digestive system of cats, difficulty in defecation is a common disease. Short-term constipation may be caused by feeding or environmental factors, but in the long term, it is necessary to check whether it is caused by disease. Sometimes drug treatment is required. We We have discussed the effects of traditional Chinese medicine on digestive system diseases. This time we will look at the methods of Western medicine. ​​​​​​

As the name suggests, laxatives are a type of drug that promotes the smooth discharge of feces. In Western medicine, they can be divided into three categories according to their mechanism of action:

1. Volumetric laxatives

These drugs are salt ions that are difficult to be absorbed by the intestinal wall and are easily soluble in water. The pharmacology is that after oral administration, they can form a hypertonic solution in the intestinal lumen, absorb a large amount of water, and prevent intestinal water from being absorbed. Increased water content can soften feces, increase intestinal volume, stimulate intestinal mucosa, promote intestinal peristalsis, and cause defecation.

　①Sodium sulfate

Sodium sulfate is a volumetric laxative that can promote defecation reflex or smooth defecation. Sodium sulfate is not easily absorbed by the intestinal wall but is easily soluble in water. It forms a hypertonic salt solution in the intestine. Therefore, it can absorb a large amount of water and prevent the intestinal absorption of water, increase the intestinal volume, irritate the intestinal mucosa, and cause intestinal tuberculosis. Peristalsis speeds up defecation. Its cathartic effect is weaker than that of magnesium sulfate and there are no adverse reactions caused by hypermagnesemia. Sodium sulfate also antagonizes barium ions in the body. Barium ions are an extremely powerful muscle poison that can cause excessive irritation to smooth muscles, skeletal muscles, cardiac muscles, etc., and lead to paralysis and paralysis. Moreover, barium ions can change the permeability of cell membranes, allowing a large amount of potassium to enter the cells, resulting in hypokalemia. Sodium sulfate can form insoluble barium sulfate with barium ions, thereby blocking the toxic effects of barium ions. Sodium sulfate has the effects of purging fire and laxative, moistening dryness and softening hardness, clearing fire and reducing swelling.

As a stomachic drug, sodium sulfate needs to be used in conjunction with other drugs. When used to treat large intestinal constipation, the appropriate concentration of sodium sulfate is 4% to 6%. It should be noted that sodium sulfate is prohibited from being used in conjunction with calcium salts.

2. Lubricating laxatives

Lubricating laxatives are derived from animals, plants and minerals. It is medium oily, so it is also called oil laxative.

　①Liquid paraffin

It is a colorless and transparent oily liquid, odorless and tasteless, and does not show fluorescence in sunlight. This product is a laxative. It is not absorbed in the intestines after oral administration and plays a lubricating effect. It also prevents the absorption of water in the intestines. This product has a mild laxative effect and is non-irritating. It is used for small intestinal obstruction, constipation, etc. However, liquefied paraffin should not be used repeatedly for a long time because it hinders the absorption of vitamin A, vitamin D, vitamin E and calcium and phosphorus.

3. Stimulant laxatives

After irritating drugs are taken orally, they will be metabolized and decomposed in the intestines to produce active ingredients, which will cause intestinal mucosal damage.Membrane receptors produce chemical stimulation that promotes intestinal peristalsis and induces diarrhea.

　①Castor oil

This product is a fatty oil obtained by extracting and refining the mature seeds of the Euphorbiaceae plant castor oil. This product is an almost colorless or slightly yellow clear viscous liquid with a slight odor and a light and then slightly pungent taste. This product is easily soluble in ethanol and can be mixed with absolute ethanol, chloroform, ether or glacial acetic acid.

Castor oil is used for constipation, especially to cleanse the intestines before surgery or diagnostic tests. Castor oil itself is non-irritating and only has a lubricating effect. After oral administration, it is decomposed into glycerin and ricinoleic acid by the action of pancreatic lipase in the intestine. The latter produces sodium ricinoleate, which stimulates the receptors of the small intestinal mucosa, causing small intestinal peristalsis and leading to diarrhea. In terms of usage, castor oil should not be used for a long time, otherwise it will affect the digestive function.

In other respects, some cholinergic drugs can enhance intestinal peristalsis and promote defecation through their effects on intestinal M receptors.