laxatives

BY :SIDDHARTH PATEL

• Laxative are also called as “APERIENTS” .

DEFINATION:LAXATIVES are the drug which promote the evacuation of bowels.

• Mild laxative action are called as LAXATIVE/APERIENTS.• Strong laxative are called as CATHARTICS/PURGATIVE

CLASSIFICATION:

1. Bulk laxative: ex: cellulose derivative(methyl cellulose),isabgol ,agar ,bran , sterculia gum.

2. Stool softeners : ex: Docusate sodium (DOSS)(nature: surfactant & stimulant),liquid paraffin , liquid suppository , arachis oil.

3. OSMOTIC LAXATIVE : ex: saline , Mg(OH)2 , MgSO4, PEG, non-indigestible sugar and alcohol (lactulose ).

4. STIMULANT LAXATIVE: ex: senna , phenolphthalein, bisacodyl ,castor oil, Lubiprostone .

Laxatives

Bulk laxative:Mechanisms of action

• This are the complex polysaccharides which increases the bulk by forming bulky hydrated mass in the lumen of intestine creating pressure and promoting peristaltic followed by defecation.

• It take days to produce action.• Ex: (1) Bran :It is by-product of the milling of wheat .

-The it constitute of 40% of dietary fibre -the mechanisms of action of barn is that it absorb water in intestine swells

and increases its mass.Adverse effect: (1) It is unpalatable. (2)Flatulence may occur.(3) Patients with ulceration are contraindicated.

.(2) Isabgol : In this isabgol husk is used as laxative.• It form gelatinous mass by absorbing water.• Adverse effect: it cannot be swallow easily.• It show action within 1-3 days.

(3)Methyl cellulose: dose:4-6g per day.

Stool softeners• This is surfactant come anionic detergent.

Ex:(1) DOCUSATE SODIUM(DOSS): mechanisms of action :it emulsifies prolong its content and increases the penetration of water in faeces .

Drug interaction : It should not be given with liquid paraffin as it cause synergistic effect which cause diarrhoea like effect.

– Adverse effect: cramps(painful involuntary contraction of a muscle or muscles, typically caused by fatigue or strain.) and abdominal pain occur.

-Bitter and liquid preparation cause nausea.-hepatotoxicity may occur on prolong use.

• (2) liquid paraffin: It was introduced in 19 century.

• It is less widely used.• MOA: It soften the stool by lubricating and

coating them.• Adverse effect: small amount pass into intestine…

(in general if we take 100mg then only 10mg will show effect in intestine.)

• It carry away fat soluble vitamin with it.

Docusate

STIMULANT LAXATIVEThis drug stimulate intestinal mucosa which promote

peristalsis and cause defecation.• It take few minute to produce it action.• EX: (1) Bisacodyl: It is often given as suppository

which cause defecation within 15 to 30 minute.• (2) phenolphthalein: It is an indicator but also act as

stimulant laxative .• Adverse effect: It causes pink urination.-on large doses it causes “ STEVEN JOHNSON’S

SYNDROME” is reported.(A rare, serious disorder of the skin and mucous membranes.)

• (3)Senna and Dendron : it is naturally occurring glycosides which directly stimulate intestinal mucosa and causes laxative action.

• (4)Castor oil : it is a fixed oil obtained from the seeds of Ricinus communis.

• It is hydrolysed in the small intestine to ricinoleic acid which acts as local irritant that increases intestinal motility .

Bisacodyl Senna Lubiprostone

OSMOTIC LAXATIVE• This drug show osmotic difference between intestine

and blood & results in softening of intestine content which promotes peristalsis & followed by dedication.

• Ex:(1) MgSO4(epsom salt) :-dose=5-15g and it is bitter in taste.

• (2) Mg(oH)2(milk of magnesia) :-30ml of 8% w/with suspension.

• (3) Na2SO4 (glauber salt) :- dose:-10-15g and it is bad in taste.

• (4)DISODIUM PHOSPHATE ( Na2Po4):- dose=6-12g• (5) Sodium potassium tartrate (rochelle salt) :-

dose=8-15g• Pleasant in taste. • (6) lactulose :- it is semi synthetic disaccharides

of fructose and galactose . • It take 2-3 days to act. • Adverse effect:- flatulence, cramps, diarrhoea ,

electrolyte disturbance. • On high dose hepatotoxicity occur. • Tolerance is develop. • (6)Macrogols (PEGS):- it consists of inert ethylene

glycol polymers, which act in same ways.

THANK YOU