Antimotility drugs

Question 1

What are examples of antimotility drugs?

Answer 1

• Loperamide
• Codeine phsophate

Question 2

What is the mechanism of action of loperamide?

Answer 2

Opioid similar to pethidine that does not penetrate CNS - no analgesic effects. It is an agonist of the opioid mu-receptor in the GI tract. This increases non-propulsive contractions of the gut smooth muscle but reduces propulsive contractions. Transit of bowel contents is slowed and anal sphincter tone is increased

Question 3

What effect does slowed gut transit have on water content?

Answer 3

Allows more time for water absorption, which hardens stool

Question 4

When would you use codeine phsophate over loperamide?

Answer 4

If analgesia was also required

Question 5

What are side effects of antimotility drugs?

Answer 5

• Constipation
• Abdominal cramping
• Flatulance
• Opioid toxicity - codeine toxicity

Question 6

Why should you not give loperamide in acute ulcerative colitis?

Answer 6

Increases risk of toxic megacolon and perforation

Question 7

Why should loperamide be avoided in c. diff infection?

Answer 7

Risk of toxic megacolon and perforation

Question 8

When should you avoid using loperamide?

Answer 8

• Acute ulcerative colitis
• C. diff
• Acute bloody diarrhoea
• E. coli infection

Question 9

Why should you avoid using loperamide in someone with E. Coli?

Answer 9

Increased risk of HUS

Question 10

What are indications for using antimotility drugs?

Answer 10

Diarrohea - usually in the context of IBS or viral gastroenteritis