Constipation

Question 1

Symptoms

Answer 1

• Dry, hard or lumpy stools
• Less than 3 times a week
• Straining, abdominal pain, bloating

Question 2

Red flags

Answer 2

• New onset 50+
• Anaemia
• Abdominal pain
• Weight loss
• Blood in stool

Question 3

Bulk forming: MOA

Answer 3

• Inc faecal mass
• Onset: 72H
• First line: after dietary measures

Question 4

Bulk forming: side effect

Answer 4

Intestinal obstruction
- Counsel: adequate fluid intake, swallow water, not before food
- Caution: elderly or debilitated patients

• Bloating + flatulence
• Cramping
• Hypersensitivity (ispaghula husk)

Question 5

Osmotic: MOA

Answer 5

• inc water in colon
• Onset: 2-3 days, 48H - lactulose
• eg. macrogol, lactulose + magnesium hydroxide
• Second line: add or switch if stools remain hard

Question 6

Osmotic: side effect

Answer 6

• Lactulose: diarrhoea, bloating, flatulence, cramps, nausea
• Dehydration (Counsel: drink plenty of fluids)

Question 7

Stimulant: MOA

Answer 7

• inc intestinal motility
• onset: 6-12H, glycerol suppositories: 15-30 min
• Counsel: take in evening to go to toilet in morning
• Third line: add if stools soft but difficult to pass

Question 8

Stimulant: side effect

Answer 8

• Abdominal cramps
• CI: intestinal obstruction
• Diarrhoea
• HypOkalaemia
• Lazy bowel syndrome
• Red-brown urine (Senna)
• MHRA: New OTC measures: pack size 2x short courses 12+
• Dantron: carcinogenic, red urine + local irritation

Question 9

Stool softener: MOA

Answer 9

• RED surface tension and allows more fluids to enter the stool, which makes it easier to pass
• eg. liquid paraffin

Question 10

Stool softener: side effect

Answer 10

• Anal seepage + irritation
• Granuloma in GI tract
• Lipoid pneumonia
• Malabsorption of fat soluble vitamins: A, D, E, K

Question 11

Laxatives with stool softening properties

Answer 11

• Methylcellulose (bulk forming)
• Docusate (weak stimulant)
• Glycerol (rectal stimulant)

Question 12

Chronic constipation treatment

Answer 12

• Selective 5-HT4 agonist
• Guanylate cyclase-c agonist

Unresponsive to 2+ laxatives (from diff classes):
- Prucalopride
- Linaclotide: moderate-severe IBS w constipation

Question 13

Opioid induced constipation treatment

Answer 13

Osmotic + stimulant (OR docusate) - need to be co-prescribed

• Co-danthramer + co-danthrusate - palliative only
• Methylnaltrexone + naloxegol (inadequate response to other laxatives)

AVOID bulk forming laxatives: intestinal obstruction + colic

Question 14

Children treatment

Answer 14

Macrogol
- + stimulant laxative → + lactulose or laxative w stool softening properties (docusate, glycerol, suppositories or methylcellulose)

Question 15

Pregnancy + breastfeeding treatment

Answer 15

• Bulk forming
• Glycerol suppositories (if response inadequate)
• AVOID near term/unstable pregnancy: bisacodyl/senna