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1. PURGATIVES-
Classification& Osmotic
Purgatives

2. CLASSIFICATION
• 1)Bulk forming
Dietary fibre: Bran,phyllium(plantago)
Isphagula,Methyl cellulose
• 2)Stool softener
Docusates(DOSS),Liquid paraffin
• 3)Stimulant purgatives
A.Diphenylmethanes-
Phenolphthalein,Bisacodyl,Sodium picosulfate
B.Anthraquinones(Emodins)-

3. Contd....
-Senna,Cascara sagrada
C) 5-HT4 agonist
Tegaserod
D) Fixed oil
Castor oil
• 4)Osmotic purgatives
Mg salts- Mg(SO)4,Mg(OH)2
Na salts-Na2(SO)4,Na3(PO)4
Na.K.tartarate
LACTULOSE

4. Osmotic Purgatives
Solutes not absorbed in the intestine→Retain
H2O osmotically→distent the
bowel→increasing peristalsis indirectly(basis
of osmotic purgatives)
All inorganic salts used as osmotic pugatives
have similar action- differ only in
dose,palatability&risk of systemic toxicity

5. Mg++ ions release cholecystokinin which may aid
purgative action of Mg salts.
• Mg(SO)4(Epsom salt):5-15g,bitter in taste
• Mg(OH)2(as 8% w/w suspn-milk of magnesia)
:30 ml , bland in taste, also used as antacid
• Na2(SO)4(Glauber’s salt):10-15g,bad in taste.
• Na3(PO)4:6-12g, taste is not unpleasant.
• Na.K.tartrate(Rochelle salt):8-15g, relatively
pleasant tasting.

6. LACTULOSE
A semi synthetic disaccharide of fructose and
lactose.
Neither digested nor absorbed in the small
intestine.
It is broken down in the colon by bacteria to
osmotically more active products
• Dose-10g BD taken with planty of water

7. The breakdown products of lactulose are
acidic→NH3 produced by bacteria in colon is
converted to ionised NH4+ salts and is not
absorbed
So it causes redn in bld NH3 conc. By 25-50%
in patients with hepatic encephalopathy.
(for this purpose,dose shud b increased to 20g
TDS or more)

8. • C/I of osmotic purgatives:-
Mg. Salts are contr. Indicated in RENAL INSUFFICIENCY
Na. Salts shud not b given to patients of CONGESTIVE
HEART FAILURE and other Na+
retaining states.
• Uses-preparation of bowel b4 surgery& colono-
scopy,in food/drug poisoning& as after purge in
treatment of tapeworm infestation.
They r practically not used 4 the treatment of
constipation bcoz afterconstipation is common.

9. THANK U....