Constipation

Question 1

Symptoms

Answer 1

• Infrequent stools
• Difficulty passing stools
• Sensation of incomplete emptying.

NICE definition = less than 3 times a week

Question 2

Associated symptoms

Answer 2

• Excessive straining
• Lower abdominal pain/discomfort
• Bloating

Question 3

Red flag symptoms

Answer 3

• New constipation in 50+
• Anaemia
• Abdominal pain
• Unexplained weight loss
• Overt or occult blood

Question 4

Bulk forming laxatives - examples

Answer 4

• Ispaghula husk
• Methylcellulose
• Sterculia

Question 5

Bulk forming laxatives - MoA

Answer 5

Swells in gut to increase faecal mass and stimulate peristalsis.
Works within 24 hours BUT takes 72 hours for full effect

Question 6

When are bulk forming laxatives used?

Answer 6

1st line
Small, hard stools and fibre deficient diets

Question 7

Bulk forming laxatives - side effects

Answer 7

Bloating
Cramping
Flactulence
Gut obstruction - C/I in faecal impaction/colonic atony

Question 8

Bulk forming laxatives - counselling

Answer 8

Maintain adequate fluid intake to avoid gut obstruction.
Swallow with plenty of water and not before bed

Question 9

Bulk forming laxatives - handling

Answer 9

Potent allergens - hypersensitivity reactions

Question 10

Osmotic laxatives - examples

Answer 10

• Lactulose
• Macrogols
• Phosphate and sodium citrate enemas

Question 11

Osmotic laxatives - MoA

Answer 11

Increases water in colon by drawing fluid from body/retaining fluid.
Works within 2-3 days (48 hours for lactulose)

Question 12

When are osmotic laxatives used?

Answer 12

2nd line
If stools remain hard

Question 13

Osmotic laxatives - side effects

Answer 13

Lactulose = discomfort, flatulence, cramps + nausea.
Reduce nausea by taking with water, fruit juice or meals.

Question 14

Lactulose

Answer 14

Causes osmotic diarrhoea of low faecal pH

Question 15

Macrogols

Answer 15

Sequester fluid in bowel

Question 16

Stimulant laxatives - MoA

Answer 16

Increases intestinal motility by irritating the gut lining.
Colonic nerves = senna
Colonic and rectal nerves = bisacodyl, sodium picosulfate
Works within 6-12 hours.
Glycerol suppositories = 15-30 mins

Question 17

When are stimulant laxatives used?

Answer 17

3rd line
If stools are soft but difficult to pass/incomplete emptying
Short term use only (around 1 week)

Question 18

Stimulant laxatives - examples

Answer 18

• Senna
• Bisacodyl
• Sodium picosulfate
• Glycerol
• Docusate sodium

Question 19

Stimulant laxatives - side effects

Answer 19

Abdominal cramps
Senna = urine yellow-brown

Question 20

Stimulant laxatives - excessive use

Answer 20

Hypokalaemia
Diarrhoea
Lazy bowel

Question 21

Dantron

Answer 21

Stimulant laxatives
Genotoxic
Carcinogenic - used in terminally ill patients only
Red urine
Local irritation/excoriation - avoid prolonged contact with skin in incontinent parients

Question 22

Lubiprostone + Prucalopride

Answer 22

Give if at least TWO laxatives (from diff classes) have been tried at the highest tolerated recommended dose for at least 6 months.
Prucalopride used in WOMEN only

Question 23

C/I

Answer 23

• Intestinal obstruction or perforation.
• Paralytic ileus.
• Colonic atony or faecal impaction (bulk-forming laxatives).
• Crohn’s disease or ulcerative colitis.
• Toxic megacolon.
• Severe dehydration (bisacodyl).
• Galactosaemia (lactulose).
• History of hypersensitivity to peanuts (arachis oil enema).

Question 24

Caution

Answer 24

CVD = max 2 sachets of movicol
Lactose intolerant = lactulose, may cause diarrhoea
Fluids + electrolyte disturbance
Hypokalaemia = associated with prolonged use of laxatives.