LAXATIVES/PURGATIVES/CATHARTICS

Question 1

What about laxatives?

Answer 1

=Laxatives promote evacuation of the intestine. Used to treat constipation.

=They include, cathartics, or purgatives, which
promote rapid evacuation of the intestine and
alteration of stool consistency.

Question 2

Laxatives can be subdivided into seven categories
according to their action, list the categories

Answer 2

*Bulk-forming laxatives
*Stool softeners
*Emollients
*Saline laxatives
*Stimulant laxatives
*Osmotic laxatives
*chloride channel activator

Question 3

General info about laxative use

Answer 3

=Many OTC laxatives are overused by a large portion of the population.
=Prevention and relief of constipation is better achieved through natural methods (e.g., high-fiber diet, adequate fluid intake, good bowel habits, and exercise).
=Normal frequency of bowel movements varies from daily to several times weekly.
**When constipation occurs, the cause should be identified before laxatives are used.

Question 4

I. Bulk-Forming laxatives MoA and Pharmacology

Answer 4

*Not absorbed from the GI tract.
* known as fiber supplements. They soften stool by absorbing water and increase fecal mass.
* Colon distention induces peristalsis, to facilitate defecation.

*The formulation is dissolved in water or juice,
immediately followed with another glass of fluid.
* Administered one to three times per day.

Laxative effect within 12–72 h.

Question 5

Examples of bulk-forming laxatives

Answer 5

=psyllium
=cellulose derivatives
=polycarbophil
=bran.

Question 6

Bulk-forming laxatives indications

Answer 6

• Older adults
• Laxative-dependent patients
• Simple constipation unrelieved by natural methods.
• Maintaining regularity for patients with diverticulosis and in increasing the bulk of stools in patients with chronic watery diarrhea.

Question 7

Precautions or contraindications of bulk-forming laxatives

Answer 7

Patients with acute abdominal pain, partial
bowel obstruction, dysphagia (difficulty in swallowing), or esophageal
obstruction.

Question 8

II. Stool softeners

Answer 8

=Increase the penetration of water and lipids into compacted fecal material.
=Stool softeners are surface-acting agents that moisten stool through a detergent action and are administered orally.
=Dosage required to soften stools varies widely depending on the condition and patient response.
*The onset of action:12–72 h.

Side effects are rare, with occasional mild, transitory GI cramping or rash.

Question 9

Examples of Stool Softeners

Answer 9

docusate and glycerin

Question 10

Indications for Stool softeners

Answer 10

Pregnant, nursing women and children with hard, dry stools.

Question 11

Precautions or contraindications for Stool softeners

Answer 11

=Acute abdominal pain or prolonged use (more than one week) without medical supervision.
=Avoid stool softeners that also contain stimulant laxatives.

Question 12

III. Emollients

Answer 12

=Emollients promote stool movement through the intestines by softening and coating the stool.
=Mineral oil may be administered orally and is usually effective in 6–8 h.
=Mineral oil is sometimes administered rectally as an oil-retention enema (60–120 mL).

Question 13

Side Effects of Emollients

Answer 13

*Seepage of oil from rectum, causing anal irritation
*Malabsorption of vitamins A, D, E, and K only with prolonged oral use

Question 14

Precautions or contraindications of Emollients

Answer 14

Children under 5-years, Bedridden, debilitated, or geriatric patients, Patients with dysphagia, gastric retention, or hiatal hernia, Pregnancy, Prolonged use, Concomitant use of stool softeners.

Question 15

IV. Saline laxatives

Answer 15

=Saline laxatives Include: milk of magnesia (MOM) or citrate of magnesia
=They promote secretion of water into the intestinal lumen
=They should be taken infrequently in single doses.
*The onset of action is 0.5–3 h

Question 16

Side effects of Saline Laxatives

Answer 16

=Side effects are more common when used for prolonged periods or in overdoses.
*Electrolyte imbalance, weakness, sedation, and confusion, Edema, Cardiac, renal, and hepatic complications.

Question 17

Precautions or contraindications of Saline laxative use

Answer 17

=Long-term use, Heart failure or other cardiac disease, Edema, cirrhosis, or renal disorders, concomitant diuretics, acute abdominal pain,
Colostomy

Question 18

V. Stimulant laxatives

Answer 18

 They are cathartic in action, producing strong peristaltic activity, and alter intestinal secretions
in several ways.
 Stimulant laxatives are habit forming; long-term use may result in laxative dependence and the
loss of normal bowel function.
 All stimulant laxatives produce some degree of abdominal discomfort.

 Sometimes a combination of oral preparations, suppositories, and/or enemas may be ordered
for these purposes.
 The onset of action is 0.25–8 h, depending on the preparation.

Question 19

Stimulant laxatives indications

Answer 19

=Their use should be confined to conditions in which rapid, thorough emptying of the bowel is
required :
*before surgical, proctoscopic, sigmoidoscopic, or radiological examinations, or for emptying the bowel of barium following GI X-rays) or for patients on opioid therapy.
= Sometimes a combination of oral preparations, suppositories, and/or enemas may be ordered
for these purposes.

Question 20

Stimulant laxatives examples

Answer 20

Senna, castor oil, and Bisacodyl.

Question 21

Side Effects of Stimulant laxatives

Answer 21

Common with prolonged us:
* Abdominal cramps, discomfort and nausea.
* Rectal and/or colonic irritation with suppositories
* Loss of normal bowel function with prolonged use
* Electrolyte disturbances and dehydration with prolonged use
* Discoloration of urine with Senna

Question 22

Precautions or contraindications of Stimulant laxatives

Answer 22

=Acute abdominal pain or abdominal cramping—
danger of ruptured appendix, Ulcerative colitis.

=Children, pregnant and lactating women.

Question 23

VI. Osmotic laxatives

Answer 23

=They exert an action that draws water from the tissues into the feces and reflexively stimulates evacuation.
=Lactulose response may take 24–48 h.

=Side effects include nausea, vomiting, flatulence, andabdominal cramps.

=Osmotic laxatives are also used to treat encephalopathy in hepatic failure precipitated by GI bleeding and other conditions.

Question 24

Examples of Osmotic laxatives

Answer 24

Lactulose, polyethylene glycol (PEG), and
sorbitol.

Question 25

Glycerin and Miralax

Answer 25

=Glycerin rectal suppositories or enemas usually cause evacuation of the colon within 15–60 min.
* Glycerin may produce rectal irritation or cramping pain.

=Polyethylene glycol (Miralax/ PEG) response can be seen in 0.5–3 h; but, two to four days of therapy may be required to produce a bowel movement.
*Side effects are similar to other drugs in this
category; high doses of Miralax can cause
electrolyte imbalances (hyponatremia,
hypokalemia) with prolonged or excessive use.

Question 26

PEG indication and side effects

Answer 26

 PEG is used to cleanse the colon prior to endoscopy.
 If aspirated, mineral oil can cause severe lipid
pneumonia
 Chronic use can result in decreased fat-soluble
vitamin absorption.

Question 27

VII. Chloride Channel Activators: Lubiprostone

Answer 27

=Lubiprostone (Amitiza) is a unique oral agent for the treatment of constipation. It increases intestinal fluid secretion by activating specific chloride channels in the intestinal epithelium.
=Alters stool consistency and promotes regular bowel movements without altering electrolyte balance or producing tolerance.
=Most patients experience a bowel
movement within 24 h of the first dose.

Side effects: Nausea and diarrhea, Headache, Abdominal pain and flatulence.

Question 28

Precautions or contraindications of Chloride channel activators

Answer 28

Bowel obstruction, Renal or hepatic impairment, Pregnancy and breast-feeding.

Question 29

VIII. Peripherally Acting Mu-opioid Receptor Antagonists

Answer 29

=Naloxegol (Movantik) is a new oral agent specifically designed for the treatment of constipation caused by chronic or acute opioid use.
=It works by acting on the same mu-receptors that opioids do, but selectively inhibits the mu-receptors in the GIT.
=reduces the opioid-induced delay in GI transit time, caused by opioid stimulation that leads to constipation.
=It does not have action at other mu-receptors in the body, leaving analgesic properties of the opioid intact with no potential for abuse.

*Side effects: Nausea and diarrhea, Flatulence.

Question 30

Precautions or contraindications for Peripharally acting mu-antagonists

Answer 30

=Severe GI obstruction
=Patients with disruption to blood–brain barrier: may experience opioid withdrawal-like symptoms
=Severe hepatic impairment Interactions may
occur with: CYP3A4 inhibitors will increase
concentration of naloxegol.