Ch-8.4 D Pharm Pharmacology

Topic: Laxatives and purgatives

Laxatives and purgatives are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation.

 Classification of drugs:

1. Bulkforming Dietary fibre: Bran, Psyllium (Plantago) Ispaghula, Methylcellulose

2. Stool softener: Docusates (DOSS), Liquid paraffin

3. Stimulant purgatives:

a) Diphenylmethanes: Phenolphthalein, Bisacodyl, Sodium picosulfate

(b) Anthraquinones (Emodins): Senna, Cascara sagrada

(c) 5-HT4 agonist: Prucalopride

(d) Fixed oil: Castor oil

4. Osmotic purgatives:

a) Magnesium salts: sulfate, hydroxide

b) Sodium salts: sulfate, phosphate Sod. pot. Tartrate, Lactulose