3. Laxatives. Classification. Mechanism of action. Indications for use. Side effects. Contraindications Comparative evaluation of drugs.

Classification:

I. Laxatives that inhibit absorption and stimulate secretion. -Inorganic substances Saline laxatives Magnesium sulfate Sodium sulfate --Organic remedies 1. Of plant origin a) Vegetable oils-Castor oil b) Preparations containing anthraglycosides: Buckthorn extract liquid (dry), Rhubarb tablets, Infusion of senna leaves 2. Synthetic means: Phenolphthalein , Izaphenin, Bisacodyl, Guttalax II. Means that increase the volume of intestinal contents: Seaweed, Laminarid, Wheat bran, Lactulose (normase), Forlax, Mucofalk III. Means that lubricate the intestinal mucosa and soften feces :: Vaseline oil, Almond oil IV. Laxative suppositories (gas-generating candles): Ferrolax, Calciolax

Laxatives that inhibit absorption and stimulate secretion. Means to increase the volume of intestinal contents

Means that lubricate the intestinal mucosa and soften stool

Inorganic laxative suppositories organic

Indications: Drugs of this group are used to obtain a strong single laxative effect, for example, for: - acute poisoning; - acute constipation; - before surgery to cleanse the intestines; - before proctological studies; - together with some antihelminthic drugs for expelling worms.

Herbal origin Preparations of this group are used to obtain a strong single laxative effect, for example, for: - acute poisoning; - acute constipation; - before surgery to cleanse the intestines; - before proctological studies; - together with some antihelminthic drugs for expelling worms.

Synthetic drugs Used for chronic constipation of various etiologies caused by hypotension and sluggish peristalsis of the large intestine, incl. in elderly people, in bedridden patients, in the postoperative period, after childbirth; for stool regulation for hemorrhoids, proctitis, anal fissures; cleansing the intestine during preoperative preparation, to prepare the colon for instrumental and X-ray examinations. It is used for chronic constipation, diseases and conditions, the treatment of which should be accompanied by mild defecation (hemorrhoids, anal fissure, pregnancy, postoperative period after surgery on the rectum), diarrhea of ​​various etiologies, irritable bowel syndrome.

Side effects: inhibition of the structures of the brain that regulate respiration and vascular tone, causes relaxation of vascular smooth muscles and leads to a decrease in blood pressure. Magnesium sulfate can cause sedative or hypnotic effects, disrupt neuromuscular transmission or uterine contractile activity. moderate spastic abdominal pain; - malabsorption; - hypokalemia some patients may experience intestinal colic, palpitations and even collapse. There are allergic reactions (up to shock) with repeated use of the medication. possible allergic reactions to the components of the drug, increased gas formation in the intestines in the first days of therapy, feeling of a full intestine. With prolonged use, the prdigestion process.

Contraindications: heart or renal failure; acute poisoning with fat-soluble poisons (kerosene, gasoline). Intestinal obstruction, acute inflammation of the gastrointestinal tract, strangulated hernia, intestinal bleeding, Acute proctitis, acute hemorrhoids, intestinal obstruction, strangulated hernia, peritonitis, acute gastrointestinal diseases, uterine bleeding, cystitis.

Mechanism: Gastrointestinal drugs dissociate to form ions that are poorly absorbed. This leads to an increase in osmotic pressure in the intestinal lumen, which prevents the absorption of the liquid part of the chyme and digestive juices. The volume of intestinal contents increases, this leads to irritation of mechanoreceptors and increased peristalsis. Saline laxatives act mainly in the small intestine. The effect occurs in 4 - 6 hours from the moment of administration.

In the duodenum, under the action of pancreatic lipase, castor oil is hydrolyzed with the release of glycerol and ricinolic acid, the latter irritates the cells of the intestinal mucosa, inhibits the process of active absorption of water and electrolytes, which leads to increased motility and accelerates bowel emptying, and glycerin, obstruction - kinky mucous membrane, facilitates the movement of contents. The effect appears after 2-6 hours

The mechanism of action consists in inhibition of Na + -K + -ATPase of the intestinal mucosa membranes (absorption of sodium and water is impaired) and in influencing the effects of calcium in intestinal smooth muscle cells. The drugs of this group are not absorbed in the gastrointestinal tract, they adsorb water on their surface, swell, thereby increasing the volume of the indigestible residue. Thus, they represent a mechanical stimulus, since they cause stretching of ki.the intestine and increase its motor skills. When taken orally, the feces are not absorbed and soften.