Medicines for constipation

Constipation is an intestinal malfunction, which results in a difficulty in evacuating stools and insufficient, infrequent or irregular defecation, with the emission of hard and compact stools. Constipation is more common in women and the elderly, who report greater strain and a feeling of a blocked anus, than in middle-aged people.

Constipation is not a disease but a disorder, a symptom, which can easily degenerate into diseases of various kinds, such as intestinal obstruction, chronic abdominal pain, megacolon, volvulus, fecaloma, up to colorectal cancer . The causes that most frequently lead to constipation are to be found above all in a very hectic life, with a diet low in fiber and liquids, and little, if not completely absent, motor activity. Other collateral causes can be a drastic change in the daily routine. , a hypotonic colon, the presence of colon tumors, a neuro-muscular dysfunction of the rectum-anal region, the use of iatrogenic substances, such as opioids, antimuscarinics, antacids. Last but not least, the psychological aspect, as stress, anxiety, emotional stimuli, fear and repressed aggression are able to alter gastric and intestinal motility. To defeat constipation it is necessary to adopt a healthy and balanced daily diet , and engage in a fair amount of physical activity; if this is not enough, certain laxative drugs can be used.
It is good to clearly distinguish the laxative effect from the purgative one: the laxative action causes an "evacuation of soft but compact stools; on the other hand, the purgative action causes a" diarrheal type evacuation, therefore more fluid. The same laxative in excessive doses it can be purgative.

It often happens that these laxative drugs - which do not require a medical prescription - are used incorrectly and often excessively, especially by the elderly; this tends to worsen the constipation effect, making the intestine insensitive to the drugs themselves, and inducing dehydration.

We can distinguish several pharmacological categories useful against constipation.
Mass laxatives: these are hydrophilic colloids to be administered with large volumes of water to increase fecal mass and intestinal peristalsis; among these we find the common dietary fibers and psyllium seeds. The effect is not immediate but it takes days of treatment. Some of these preparations may contain sugars, so they are not recommended for diabetics.
The osmotic saline purgatives such as magnesium salts, lactulose and mannitol; they draw water into the intestinal lumen by increasing the fecal mass; thus they have a powerful cathartic or diarrheal effect. Lactulose is broken down into galactose and fructose, which - subsequently fermented by the intestinal bacterial flora - give rise to acetic and lactic acid, responsible for the osmotic action. Excessive doses can cause dehydration and hypokalaemia.
The purgative stimulants irritants, which are the anthraquinone glycosides contained in the senna, in the frangula, in the aloe juice and in the cascara. These drugs act at the level of the enteric nervous system, divided into: myenteric plexus, located between the longitudinal and circular muscles of the muscular tunic and submucosal plexus located between the submucosa and the circular or internal muscular tunic; in any case they are independent enteric neuronal cells, communicating with each other and sensitive to the stimuli of the ortho and parasympathetic; these two branches of the autonomic nervous system then modulate the contraction of the longitudinal and circular muscles. The purgative irritants stimulate the sensitive fibers of these neurons at the level of the circular and longitudinal muscular layer, thus increasing intestinal peristalsis. The active anthraquinone glycosides are pro-drugs; taken orally, they have a low bioavailability, and at the pre-intestinal or intestinal level they are metabolized to free anthraquinones, which immediately activate enteric neurons. They are absolutely contraindicated in case of inflammatory diseases, intestinal obstructions, pregnancy and menstrual period, as they can cause a contraction of the uterine wall, hemorrhoids and diverticulosis. The most obvious side effects are abdominal cramps and severe losses of electrolytes, especially potassium.
The stool softeners, of a mineral or glycerin nature, can be taken orally or rectally, by means of suppositories or micro-enemas. Even these drugs against constipation, if used in an exaggerated way, are dangerous; they are in fact addictive drugs, gastrointestinal disorders such as spastic colitis, excessive loss of electrolytes and perforation of the appendix (if it is inflamed).