Gastrointestinal (Laxatives)

Question 1

Examples of drug (Laxatives)

Answer 1

• Lactulose

- Senna

Question 2

Mechanism of action (Laxatives)

Answer 2

• Lactulose – reduces water reabsorption in intestine; it pulls water into the bowel and thus promotes distention and movement
• Senna – stimulant/irritant agent

Question 3

Indications (Laxatives)

Answer 3

• Constipation
• Pregnancy
• Prophylaxis in opiate analgesic use

Question 4

Side-effects (Laxatives)

Answer 4

• Dehydration
• Salt loss
• Abdominal cramps
• Fatigue

Question 5

Important pharmacokinetics/pharmacodynamics (Laxatives)

Answer 5

• Lactulose - consists of monosaccharides: fructose and galactose. Breakdown of this in the intestine by colonic bacteria increases osmotic pressure
• Senna - recommended for short term use only. Risk of organ failure with long term use or abuse.

Question 6

Patient information (Laxatives)

Answer 6

• Take liberally without regard to meals

Question 7

Other information (Laxatives)

Answer 7

• Bulk producing agent – adds more substance so that they can pass through intestine easily (lactulose)
• Stool softeners – adds more water and fat into the stool
• Stimulant or irritant – acts on intestinal mucosa and alters water and electrolyte secretion (senna)
• Hydrating agents – intestines hold more water (milk of magnesia)