Constipation

Question 1

Causes

Answer 1

Inadequate fibre - fibre adds bulk to stools and improves bowel function

Inadequate fluid

Medication - Painkillers (codeine, morphine), some antacids (aluminium), some antidepressants, iron tablets

Medical conditions - hypothyroidism IBS some bowel disorder

Pregnancy - hormonal changes affect bowel movement

Question 2

Red flags

Answer 2

New onset for over 50s

Anaemia

Abdominal pain

Unexplained weight loss

Blood in stools (indicator of gi cancer)

Question 3

Pneumonic for laxatives

Answer 3

BOSS

B- Bulk (bran, ispaghula husk, sterculia, methyl cellulose)

O- Osmotic (macrogols [laxido, lactulose]

S- Stimulant - (Bisacodyl, Senna)

S - Softeners (liquid paraffin)

Other lincalotide, prucalopride

Some have dual action

Question 4

How laxatives work?

Answer 4

TABLE ON PHONE
BULK FORMING
ispaghula husk, bran, sterculia, methylcellulose (softener too)

• Increase bulk in stool
• onset of action up to 72hrs
• have adequate fluid intake to prevent intestinal obstruction
• ADRs Bloating, Cramps, Flatulence

Stimulants
Bisacodyl, Senna, Sodium picosulfate, Glycerol, Co-Danthramer, Docusate (softener too).

• They increase intestinal motility so can cause abdo cramps. (AVOID in intestinal obstruction)
• Onset 8-12hrs. Best to take at bed time.
• Suppositories stimulants are quicker happen in 20-60 mins.
• ADRs: Abdo cramps, Abuse risk which can cause HYPOKALAEMIA (only this type effects electrolytes).
• ALL only used in <12 if given advise from prescriber 1st. 12-17 should be under pharmacist supervision.
• STIMULANT only used IF OTHERS FAIL.
• Large packs not GSL anymore
• Co-Danthramer & Co-Danthrusate (reserved for terminally ill ppl BC carcinogenicity and colours urine red.

Faecal softeners
Decrease surface tension and increase penetration of liquid in to faeces.
- Liquid paraffin - Avoid anal seepage [involuntary loss of bowel contents] with prolonged use. - This 1 can cause malabsorption of fat soluble Vits (ADEK)
- Docusate sodium - Mainly softener but has weak stimulant action. Dual actor.
- Peanut (Arachis) enemas soften and lubricate faeces.

Osmotic
Lactulose, Macrogols 3350
They increase amount of water in large intestine either by drawing fluid from the body in to the bowel or maintaining fluid within the bowel.
- Lactulose can take 2 days for max effect.
- ADRs lactulose: Abdo pain, Bloating, Electrolyte imbalance.
- Macrogols act FASTER.
- Stronger osmotic are used to clear bowel quicker (Phosphate enemas, magnesium salts)
- Lactulose ALSO USED TO TREAT HEPATIC ENCEPHALOPATHY (problem with liver that affects the brain).

Question 5

Laxative abuse

Answer 5

Can lead to HYPOKALAEMIA

Question 6

Drugs that CAUSE constipation

Answer 6

GPHC EXAM Q.
WHICH DRUGS CAUSE CONSTIPATION?
Answer:
Very old aunties get constipation.

Verapamil
Opiates
Anti-Muscarinics
Antihistamines
Anti-epileptics
Antispasmodics
Antipsychotics
Antidepressants
Antacids (Aluminium)

Question 7

Management of Constipation

Answer 7

BOS (Bulk, Osmotic, Stimulant)
Short duration constipation
Pregnancy/BF
Chronic constipation

SPC is BOS (mnemonic)

OS (AVOID BULK)
Faecal impaction (OS)
Opioid induced (OS/Naloxegol/Methylnaltrexone)
Children (O - Macrogol)

Children dont FOChOS
(FOC - OS)

Question 8

Patient and Carer Advice

Answer 8

BULK Preparations swell in contact with liquid so should be carefully swallowed with water and SHOULDN’T be taken immediately before bed.

• Don’t want stomach to swell at night BC it can lead to blockages in GI tract.