laxatives

Question 1

What is the 1st line treatment for constipation in children and young people?

Answer 1

polyethylene glycol 3350+ electrolytes using an escalting dose regime. Movicol plain sachets and liquid containing macrogol: a form of osmotic laxative. It contains sodium bicarbonate, sodium chloride and potassium chloride. May be mixed with a cold drink.

Question 2

what is the second line treatment for constipation in children and young people?

Answer 2

add a stimulant laxative, e.g. Bisacodyl, if polyethylene 3350+ elecrolyte does not lead to disimpactation after 2 weeks. Another 2nd line treatment- substitute a stimulant laxative singly or in combination with an osmotic laxatives such as lactulose if polyethylene is not tolerated.

Question 3

what shouldnt you use as a 1st line treatment for children?

Answer 3

don’t use dietary interventions alone as first line treatment for idiopathic constipation.

Question 4

what is the 1st line treatment for constipation for adults?

Answer 4

bulk forming laxatives, whilst ensuring good hydration

Question 5

what is the 2nd line treatment for constipation for adults?

Answer 5

osmotic laxatives: such as macrogol. Lactulose is an alternative if macrogol is not tolerated. If the response is inadequate, a stimulant laxative can be added.

Question 6

Name the bulk forming laxatives:

Answer 6

ispaghula husk, methylcellulose, sterculia

Question 7

indication and MOA of bulk forming laxatives?

Answer 7

constipation, first line treatment. Contain soluble fibre. They act by retaining fluid in stool and increase faecal mass which stimulates peristalsis. They have stool softening properties.

Question 8

contraindication of bulk forming laxatives?

Answer 8

colonic atony; faecal impactation; intestinal obstruction; reduced gut motility.

Question 9

side effects of bulk forming laxatives?

Answer 9

flatulence, bloating, impaction, abdominal distension

Question 10

patient/ carer advice for bulk forming laxatives?

Answer 10

takes a few days to work, need to maintain / increase fluid intake to avoid obstruction, dont take immediately before bed.

Question 11

indication and MOA of stimulant laxatives?

Answer 11

constipation; increase fluid secretion into the gut. Increases peristalsis by stimulating colonic nerves/ colonic and rectal nerves. Increases peristalsis and moves stool through the large intestine

Question 12

what are the names of the stimulant laxatives?

Answer 12

glycerol, sodium picosulohate, docusate, bisacodyl, dantron, senna.

Question 13

stimulant laxative: glycerol

Answer 13

hyper-osmotic laxative, mild suppository to evacuate rectum avoiding higher effects in GI tract. patient and carer advice: can cause stomach cramps. drink water and have high fibre foods (children)

Question 14

stimulant laxative, Docusate:

Answer 14

detergent effects on surface of intestinal bolus. Increase the mixture of fat and water, has stool softening properties.

Question 15

stimulant laxative, sodium picosulphate:

Answer 15

given orally. After metabolism in the colon it stimulates the mucosa thereby increasing the motility of the large intestine. FTR’s hydrolysed to active metabolite by bacteria in the gut. dont give in intestinal obstruction and a side effect is abdominal pain

Question 16

Bisacodyl: stimulant laxative:

Answer 16

for bowel evacuation before surgery. Dont give in acute abdominal conditions, acute inflammatory bowel disease, severe dehydration. side effect= nausea and vomiting

Question 17

stimulant laxative: dantron

Answer 17

constipation in termally ill patients. Dont give in acute abdominal conditions (children); acute inflammatory bowel disease; acute surgical abdominal conditions (adults); dehydration or intestinal obstruction. Has cardiogenic properties, increases peristalsis by stimulating colonic and rectal nerves. Side effects= abdominal pain and cramps

Question 18

stimulant laxative: senna

Answer 18

dont give in undiagnosed abominal pain/ obstruction. MOA= after metabolism of sennosides on the gut the entthrone component stimulates peristalsis thereby increasing the motility of the large intestine.

Question 19

Indication and MOA of osmotic laxatives?

Answer 19

constipation. Work by modifying the osmotic envrionment and pull water into the colon which softens stools and increases faecal mass. Increase in fluid in large bowel produces distension which stimulates peristalsis- has stool softening properties.

Question 20

names of osmotic laxatives?

Answer 20

lactulose, macrogol, magensium salts, sodium acid phosphates (rectal use) and sodium citrate.

Question 21

osmotic laxative: lactulose

Answer 21

disaccharide with osmotic potential. Don’t give in intestinal obstruction or lactose intolerance. Side effects= abdominal pin, cramps, flatulence, n&v. patient/ carer advice: in children, high fibre foods, and drinking water. taken orally, upto 48 hours to work

Question 22

osmotic laxatives: macrogol

Answer 22

treatment of chronic constipation: 2nd line treatment. dont give in ileus, intestinal obstruction, severe inflammatory bowel disease or intestinal perforation. Side effects= abdominal discomfort, cramps, flatulence and N&V. Patient/ carer advice- empty sachet of contents and dissolve in 100ml of water.

Question 23

osmotic laxatives: magnesium salts:

Answer 23

rapid bowel evacuation (2-4 hours in chronic constipation). Dont give in renal impairement, risk of Mg build up and acute GI conditions. Side effects= diarrhoea and patient/ carer advice: maintain adequate fluid intake.

Question 24

osmotic laxatives: sodium acid phosphates:

Answer 24

rectal use. Bowel evacuation before abdominal, radiological procedures, endoscopy and surgery. Dont give in condtions with increases colonic absorption, GI obstruction/ inflammatory bowel disease. Side effects= electrolytes disurbances, local irritation. P/C advice= maintain hydration, no food 6 hours before surgery (suppository/ enema)

Question 25

osmotic laxatives: sodium citrate

Answer 25

enema for rapid bowel evactuation in adults and children over 3 years. dont give in acute GI conditions.