GIT

Drugs used to treat Diarrhea & Costipation

Assistant Professor
Dr. Shamil AL-Neaimy

Drugs used to treat diarrhea:

Treatment of the cause

Correction of fluids and electrolytes imbalance .

Treatment is by increasing viscosity (pectin ,kaolin ,chalk ) ,binding toxines ,delaying passage of contents (opiods) ,and decreasing the motility of intestine (by inhibiting Ach. Release ).

Drugs:

1-Diphenoxylate : related to pethidine mixed with atropine to form LOMOTIL.
Precausions : liver disease, severe colitis ,and children.

2-Diphenoxin: active metabolite of diphenoxylate .

3-Loperamide: causing abdominal cramps.


Drugs used to treat constipation:
(Laxative , Purgative , Cathartic)

Constipation:

Habitual , related to diet , psychological , drugs (opioids) , pregnancy ,or due to disease (eg DM).

Treatment is by increasing bulk and viscosity of feces and increasing motor activity of the gut.

3 groups of drugs :

1-Stimulant (irritant):

Bisacodyl: synthetic drug , stimulates sensory endings in the colon , used in elderly people causing abdominal discomfort .

Phenolphthalin: potent stimulant acts directly on colon causing skin allergy & red stool .

Senna : stimulates peristalsis .

Sodium picosulfate : used in surgery .

Oxyphenacitin : used in surgery .

Glycerol: stimulates rectum.

2-Bulking agents :

They increase volume & decrease viscosity , holding water in the gut & stimulate normal reflex.
Two groups of drugs:

I-Hydrophilic colloids .

II-Osmotic laxatives .

Hydrophilic colloids:

Prepared from indigestable parts of vegetables & seeds .
a-Bran : residue left from cereals , that has fibres consisting of cellulose , hemicellulose & non-carbohydrate polymers .It has the ability to retain water .
Side effects : flatulence , distension , & intestinal obstruction .
b-Methyl-cellulose :
c-Psyllium:
d-Agar :
e-Ispaghula :


Osmotic laxatives(saline cathartic):

Non-absorbable salts hold water in intestine by osmosis causing distension :

a-magnesium sulfate (Epson salt):
b-magnesium hydroxide:
c-magnesium citrate :
d-sodium citrate :
e-sodium sulfate :

3-Fecal softeners (emolients):

a-Surface active agent (dioctyl):

b-Liquid paraffin: inert oil, indigestible.

Drugs used to treat Irritable Bowel Disorders:
(Crohn’s disease , Ulcerative colitis)

1-Sulphasalazine: It’s a combination of sulphapyridine and 5-aminosalicylic acid ,used to treat ulcerative colitis more than crohn’s disease.
MOA: cytoprotective action ,or inhibition of breakdown of PGF2 alpha ,or by suppressing immune response.
Side Effects: serum sickness ,bone marrow suppresion ,and oligospermia.


2-Prednisolone

3-Azathioprime

4-Mercaptopurine

Drugs used to treat Hemorrhoids:

1-Soothing agents:
a-Astringents: Bismuth , Zinc oxide , and Benzylbenzoate .
b-Local anesthetics: Lignocaine.

2-Corticosteroids: Betamethasone , hydrocortisone , and prednisolone.

3-Rectal sclerosants: Oily phenol injection 5%.

Drugs used to treat gall bladder disease:

1-Ursodiol

2-Chenodiol

MOA: supress hepatic synthesis of cholesterol and cholic acids.
Side Effects: change hepatic function and diarrhea.