Pharmacology-II Dr.

Sultan Al-Kaleh
GIT Pharmacology Lect:3
 Constipation & Laxatives
I. Constipation
 Definition:
o Constipation: is infrequent bowel movements or difficult passage of stools
(typically three times or fewer per week).
 Symptoms:
 Pass fewer than three stools a week.  Hard stools.  Rectal blockage.
 Strain excessively during bowel movements.  Incomplete evacuation.
 Resisting the urge to have a bowel movement, which is sometimes cause anal pain
(haemorrhoids or anal fissures).

 Causes:  can be caused by diet, lifestyle, drugs, medical conditions.

 Diet:  Inadequate water intake.
 Inadequate fiber in the diet.
 Eating large amounts of dairy products.
o Lifestyle:  Inadequate activity or exercise or immobility.
 Drugs:  Narcotics, antidepressants, iron pills, antacids containing Ca++, Al.
 Overuse of laxatives (stool softeners) which over time weaken the
bowel muscles.
 Medical Conditions That Can Cause Constipation
 GI disorders & eating disorders, Pregnancy, Stress, depression, colon
cancer.
 Irritable bowel syndrome (constipation-predominant)
 Anal disorders (anal fissures, fistulae, rectal prolapse)
 Multiple sclerosis  Cerebrovascular events
 Neurological conditions: Parkinson's disease?
 Spinal cord tumors  Diabetes  Hypothyroidism
 Idiopathic (If the cause of constipation is unknown).
 Notes:
o When constipation persists for several weeks or longer, it is chronic.
o When idiopathic constipation occurs frequently and is associated with chronic or recurrent
abdominal discomfort that is relieved by defecation, it is termed irritable bowel syndrome with
constipation (IBS-C).

 Treatments:
 Non-pharmacological treatments:
o High-fiber diet (fresh fruits and vegetables), regular exercise (stimulate intestinal
activity), adequate fluid intake (stool softness) and Take the time for bowel
movement.

‫ سلـطان الـقـلـح‬.‫د‬ 14 )2(‫علم الدواء‬

 Pharmacology-II Dr.Sultan Al-Kaleh
II. Anti-constipation (Laxatives) Aperients/laxatives/purgatives/cathartics

I. Physical purgatives II. Chemical purgatives

Bulk forming Osmotic Saline Lubricants Stimulants/irritant
Laxatives Laxatives Laxatives Laxatives Laxatives
 Absorb water → swell  Retain H2O in Intestine   cholecytokinin     sticking on small  Stimulate intestinal wall →
M.O.A → ↑ fecal content → → soft stools & bulk motility & fluid intestine wall   pass contraction → ↑ motility
stimulate peristalsis forming secretion  defecation of stools
 Dietary fibers e.g. bran  Lactulose (Duphalac ®)  Epsoms salt MgSO4  Mineral oil e.g.  Mild: castor oil
 Glycerin supp ‫ملح االوجليزي‬ liquid paraffin  Moderate:
 Galuber salt Na2SO4 – Bisacodyl (Dulcolax®)
 Polyethylene glycol ‫ملح جابر به حيان‬ – Phenolphathaline
Drugs
 Mg citrate
– Senna,
– Cascara,
 Mg(OH)2 (Mg hydroxide) – Senega
 Severe: Colocynth
Site of
Small & large intestines Colon Small & large intestines Colon Colon
action
Onset of Oral: 0.5-3hrs
12-72hrs 12-72hrs 6-8hrs 6-12hrs
action Rectal: 2-15min
N.B

Notes:
– Lactulose used Used with neomycin for treatment of hepatic coma ‫ٌستخذم ألًه ال ٌوتض‬
– Mg(OH)2 found as milk of magnesia and in antiacids.
– Colocynth not used due to may lead to death.
– All chemical laxatives are irritant agents.

‫ تحتىي على قشزة القوح وفٍها هادة السٍلٍلىس وفً الوعذة توتض الواء فتكىى هٌتفخة فٍشٌذ حجن الفضالت فتضغظ على جذار األهعاء فتحفش جذار األهعاء على الحزكة وكذلك تقلل هي اهتصاص الواء فٍشٌذ كوٍة الواء فً الفضالت وهذا‬:Bran
‫ٌسهل خزوجها هي القٌاة الهضوٍة‬

‫ سلـطان الـقـلـح‬.‫د‬ 15 )2(‫علم الدواء‬

 Pharmacology-II Dr.Sultan Al-Kaleh
Anti-constipation/ Laxatives/Purgatives
Dosage
Generic name Brand name Uses Dose Company name
form

Student Name:……………………… Level:…………………. Institute:……………… Date: / /2023

‫ سلـطان الـقـلـح‬.‫د‬ 16 )2(‫علم الدواء‬