drug management of constipation, diarrhoea and pancreatic insufficiency

Question 1

causes of constipation

Answer 1

• dietary - inadequate calorie/fibre intake
• medical conditions: colon cancer, parkinsons, hypotthyroidism, electrolyte disturbances, myopathies
• drugs: opioids, 5-HT receptor antagonists, TCA, CCB
• idiopathic

Question 2

classification of constipation

Answer 2

normal/slowed transit constipation
defecatory disorders/pelvic floor dysfunction
- impaired rectal evacuation/can have normal or slowed chronic transit

Question 3

non-pharmacological measures

Answer 3

• increasing fluid intake/no clear evidence
• physical exercise
  probiotics - may accelerate chronic transit
• dietary fibre

Question 4

dietary fibre

Answer 4

soluble or insoluble
usually first line therapy but not useful in drug induced
tales time to have an effect
main side effect is bloating

Question 5

osmotic laxatives

Answer 5

work by increasing water content of stools

• polyethylene glycol
• magnesium citrate
• sodium phosphate
• non absorbable carbohydrates

Question 6

stimulants

Answer 6

encourage bowel motility

• Senna
• decussate sodium
• sodium picosulphate
• bsacodyl

Question 7

5-HT4 receptor antagonists

Answer 7

stimulates colonic mass movement
provides propulsive force for defacation
no effect on QT unlike older agents

Question 8

opioid antagonists

Answer 8

mythylnaltrexone
specifically for opiod induces constipation in the palliative care setting, rapid onset of action
does not cross the blood brain barrier

Question 9

guanylate cyclase-C receptor agonists

Answer 9

linaclotide
- receptors line the Gi tract, have a role in key physiological functions
stimulates intestinal fluid secretion and transit

Question 10

acute causes of diarrhoea

Answer 10

acute

• mostly infective - mostly viral
• treatment aims to maintain fluid and electrolyte balance
• treat underlying cause if appropriate
• anti-diarrheols assist comfort

Question 11

chronic causes of diarrhoea

Answer 11

• malabsorption
• inflammatory bowel disease
• medications
• irriatable bowel disease
• treat disease and use anti-diarrhoea drugs for comfort

Question 12

bulking agents

Answer 12

• used to improve the solidity of stools in patients with irritable bowel disease in stoma
  plant fibre, guar gum, methyl cellulose

Question 13

u-opioid receptor agonists

Answer 13

• reduced gut propulsive activity
• diphenoxylate, often in combination with atropine
• loperamide, also has some antimuscarinic activity
• codeine sulfate, risk of dependance

Question 14

cholestryamine

Answer 14

bile acid sequestrate
non-digestable resin that bin bile acids leading to increased excretion
up to 4 times/day
used in
short bowel syndrome
irritable bowel disease (diarrhoea phenotype)

Question 15

cholestyramine used in

Answer 15

short bowel syndrome

irritable bowel disease (diarrhoea phenotype)

Question 16

most common causes of exocrine pancreatic insufficiency

Answer 16

chronic pancreatitis

cystic fibrosis

Question 17

symptoms of exocrine pancreatic insufficiency

Answer 17

streatorrhoea (floating stool), weight loss, fatigue, flatulence

secondary complications are
anaemia, fat soluble vitamins deficiency

Question 18

treatment of pancreatic insufficiency

Answer 18

creon or panzytrat (porcine pancreatic extract)

• lipase, amylase and proteases
• encapsulated to protect enzymes in low stomach pH, PPI can be used to further reduce this titrate dose too clinical effect, taken art the time of meal
• at very high doses has been associated with colonial strictures/fibrosis