1. Laxatives & Purgatives By: Professor: ALI A MUSTAFA Faculty of Medicine King Fahad Medical City King Saud Bin Abdulaziz Univ. For Health Sciences

2. Constipation Causes of Chronic constipation: 1- Lack of fibre in diet 2- Use of certain drugs 3- Chronic illness 4- Disturbance of neurogenic responses 5-Imbalances in hormonal secretions

3. Constipation Intermittent constipation can be prevented by: 1-High fibre diet 2-Adequate fluid intake 3-Regular exercise 4-Prompt response to natural call

4. Drug treatment of Constipation

5. Bulk-forming Laxatives These are hydrophilic, indigestible colloids that absorb water forming a bulky gel that distends colon and increase peristalsis. e.g. psylium and methylcellulose (natural) Synthetic filire e.g. Polycarbophil

6. Stool Softeners They soften stools allowing water and lipids to penetrate. They are given orally rectally examples: docusate ( Oral or enema) or glycerin suppository. Minerals oil: lubricates fecal material and retards water absorption from the stools. Mineral oil aspiration – may lead to lipids pneumonitis Mineral oils: impairs the absorption of fat –soluble vitamins (ADEK)

7. OSMOTIC Laxatives Non-absorbable Sugars or Salts Magnesium oxide (Milk of magnesia) is a commonly used laxatives. It should not be used for long periods in patients with renal insufficiency-may lead to hypermagnesemia.

8. Sorbitol and Lactose These are non-absorbable sugars used to present or treat chronic constipation. Metabolized by colonic producing severe cramps.

9. Magnesium Citrate and Sodium Phosphate These are hyperosmolar agents They draw water into the distal bowel and colon leading to high volume of liquid stool-followed by rapid relief of constipation. They can lead to intravascular volume depletion and electrolyte imbalance. Therefore they should not be used in elderly patients, weak or those who have renal insufficiency.

10. Balanced Polyethylene Glycol (PEG) Lavage solutions containing PEG are used for colonic cleansing before G.I.T endoscopic procedures. The balanced solution contains: non-absorbable,inert, osmotically active sugar (PEG) + Sodium sulphate + sodium chloride + sodium bicarbonate + potassium chloride. This solution is used for bowel cleansing with no flatus or cramps (unlike sorbitol)

11. Stimulant Laxatives (Cathartics) Anthraquinone Derivatives Aloe, senna and cascara are natural plants. They are poorly absorbed. When hydrolysed in colon, produce a bowel movement in 6-12 hours orally and within 2 hours when given rectally. Chronic use leads to brown colorations of the colon (Melanosis Coli).

12. Castor Oil Is a potent stimulant laxative Is hydrolysed in upper small intestine to ricinoleic acid which stimulates intestinal motility.

13. Serotonin 5-HT4 Receptor Agonist Tegaserod: Is a 5-HT4 partial agonist but no affinity for 5-HT3 or dopamine receptors. It stimulates 5-HT4 receptors on the pre-synatic terminal of submucosal primary afferent nerves- releasing calcitonin-gene related peptide – this stimulates enteric neurons to promote the peristaltic reflex. It increase gastric emptying and enhances small and large bowel transit. It activates C-AMP- dependent chloride secretion from colon –leading to increased liquidity of stools

14. Clinical use of Tegaserod Used in chronic constipation Effects on bowel activity seen within 48 hours. It is expensive – reserved for constipation not responding to others. Withdrawn from the market because of risk of cardiac disease

15. Thank you.