Drugs for Chronic Constipation

DEFENITION: Chronic constipation is condition in which no frequent bowel movements, typically fewer than three stools per week. With constipation, stools are typically hard, dry and small in size and usually difficult to eliminate. People with constipation may find it is painful have a bowel movement and often experience straining and bloating. Constipation is a most common gastrointestinal complaint and it is only a symptom not a disease. Main cause of constipation is not enough fiber content in the food, lack of physical activity, milk and ignoring the urge to have a bowel movement.

MEDICINES USED IN THE TREATMENT OF CHRONIC CONSTIPATION

There are lots of medications available for the treatment of constipation

1. Bulk forming agents
2. Emollient stool softeners
3. Pro kinetics
4. Osmotic agents

Bulk forming agents:

These are fibers and this is the most common medication for the treatment of constipation. Normally they are used for the long term treatment of chronic constipation or both in patients without anatomic outlets obstruction.

Commonly used bulk forming agents are

Psyllium: The dosage of psyllium is depending on the whether the preparation contains sugar or sugar free. These preparations should take water otherwise it cause obstruction.

Methyl cellulose: This is a non fermentable substance and which produces less gas. This is well tolerated than psyllium.

Emollient Stool softeners:

This makes the stool soft and stimulants increases peristaltic activity in gastrointestinal system. Commonly used emollient stool softener is docusate or senna concentrate.

Docusate sodium: It allows incorporation of water and fat in the stool, causing stool too soften. Sennocides induces defecation by acting directly in to the intestinal mucosa or nerve plexus, which stimulate peristaltic activity, increasing intestinal motility.

Osmotic agents:

Osmotic agents are used for the long term treatment of chronic constipation in patients with slow colonic transit who are refractory to dietary fiber supplement. Commonly used osmotic agents are lactulose, sorbitol and poly ethylene glycol solutions.

Lactulose: Lactulose produces an osmotic effect in the colon resulting in the bowel distension and stimulation in the peristaltic movements.

Sorbitol: Is a hyper osmotic agent which has a cathartic effect in the gastro intestinal tract.

Poly ethylene glycol solution: This is use for the gastric wash before the surgical or endoscopic procedures. This is now used as osmotic agent in smaller dose. There is a lower risk of dehydration and electrolyte imbalance with isotonic poly ethylene glycol solution. The laxative effect is because of poly ethylene glycol is not absorbed and it holds water by osmotic action through the small intestine and in the colon resulting in a mechanical cleansing.

Pro kinetic agent:

These are pro motility agent proposed to use with severe constipation- predominant symptom.

Tegaserod: This is used as a restricted treatment of irritable bowel syndrome or chronic idiopathic constipation in women younger than 55 years who meet specific guide lines. Tegaserod is a serotonin type 4 receptor partial agonist with no effect on 5HT 3 receptors. It may increase peristaltic reflux by 5HT4 activation which enhances the basal motor activity and normalizes the impaired GI motility.