constipation drugs

Question 1

name 4 bulk forming laxatives

Answer 1

○ Bran
○ Ispaghula husk
○ Methylcellulose
○ Sterculia

Question 2

• MOA for bulk forming

Answer 2

○ Relieve constipation by increasing faecal mass which stimulates peristalsis

Question 3

How to remember treatment of constipation and in pregnancy - BOSS

Answer 3

bulk
add or switch to osmotic if still hard stools
if soft stools but difficult to pass, stimulant
can also add stool softener e.g. docusate

Question 4

why is it important to drink enough fluids and avoid taking it immediately before bed - bulk forming

Answer 4

can cause intestinal obstruction

Question 5

how long does lactulose take

Answer 5

48h

Question 6

which osmotic to offer first - macrogol or lactulose

Answer 6

macrogol

Question 7

onset of action glycerol suppositories

Answer 7

15-30mins

Question 8

name the stimulant laxatives: BSSCC

Answer 8

bisacodyl
Senna
sodium picosulfate
co danthrumer
co danthrusate

Question 9

what colour does Senna colour urine

Answer 9

red brown

Question 10

which bulk forming laxative has stool softening properties

Answer 10

methylcellulose

Question 11

onset of action for stimulant laxatives

Answer 11

6-12hours

Question 12

onset of action for Senna

Answer 12

8 hours - overnight

Question 13

name 3 osmotic laxatives

Answer 13

Macrogols
Lactulose
Magnesium hydroxide (traditional remedy, less commonly used)

Question 14

SE lactulose name 4

Answer 14

Flatulence
Abdomial crams
Nausea
Bloating - avoid in IBS! Can make symptoms worse

can be troublesome in the first few days but it does settle

Question 15

other stimulants (not BSSCC)

Answer 15

glycerol (lubricant and rectal stimulant)
docusate (softener and weak stimulant)

Question 16

MHRA - new pack size restrictions for stimulant laxatives OTC - B,S,S

Answer 16

should only be used for short term occasional constipation if dietary and lifestyle measure and bulk and osmotic ineffective

GSL: adults only! 18+

limited to pack size of 2 short treatment courses.

max pack size: 20 tabs or 100ml liquid

Question 17

true or false - Senna can only be bought OTC for adults

Answer 17

false
GSL is 18+ only

but P: 12-17 year olds under advice of pharmacist

under 12 - prescriber !!

Question 18

prolonged or excessive use can cause…

Answer 18

hypokalaemia

Question 19

avoid this near term or in history of unstable pregnancy

Answer 19

Senna, other stimulants - they can stimulate uterine contractions

Question 20

how many tablets are you allowed to buy for Senna GSL

Answer 20

1 pack of 20 tablets

max strength tabs: 1 pack of 10

Question 21

how many tabs of Senna can you buy (P med) for children and adults 12+

Answer 21

up to 100 under pharmacist supervision

Question 22

minimum ml of water to take ispahgula husk with

Answer 22

150ml

Question 23

pt and carer advice isphagula husk - when to take

Answer 23

Preps that swell in contact with liquid should always be carefully swallowed with water and should not be taken immediately before going to bed

Question 24

how long does fybogel take to work

Answer 24

2-3 days

Question 25

how do osmotic laxatives work

Answer 25

increase the amount of water in large bowel either by drawing fluid from the body into bowel or by retaining the fluid they were administered with

Question 26

how long does macrogol take to work

Answer 26

1-2 days

Question 27

is lactulose absorbed from the GIT

Answer 27

no

Question 28

is lactulose ok in pregnancy

Answer 28

yes

Question 29

how do stimulants work

Answer 29

increase intestinal motility/peristalsis and often cause abdominal cramp

Question 30

how long do bisacodyl tabs take to work

Answer 30

10-20 hours

Question 31

how long do bisacodyl suppositories take to work

Answer 31

20-60 mins

Question 32

onset of action of sodium picosulfate

Answer 32

6-12 hours

Question 33

how do faecal softeners e.g. docusate and glycerol and arachnis oil enemas and liquid paraffin work

Answer 33

Claimed to act by decreasing surface tension and increasing penetration of intestinal fluid into faecal meds

Question 34

Liquid paraffin has also been used as a lubricant for the passage of stools but manufacturer advised that it should be used with caution because of its adverse effects e.g.

(3)

Answer 34

Anal seepage
Risks granulomatous disease of GIT
Lipoid pneumonia on aspiration

Question 35

how do enemas containing arachis oil (ground nut oil, peanut oil)

Answer 35

lubricate and soften impacted faeces and promote a bowel movement

Question 36

how long does oral docusate take to work

Answer 36

1-2 days

Question 37

how long does rectal docusate take to work

Answer 37

within 20 mins

Question 38

advice about taking glycerol suppositories

Answer 38

Moisten suppositories with water before insertion

Question 39

what to use 1st line in opioid induced constipation (+ an alternative, not the opioid receptor antagonists)

Answer 39

Lactulose and Senna

The osmotic laxative will draw water and soften hard stores
The stimulant laxative increases peristalsis which counteracts the anti motility effects of opioids
Alternative: docusate which is a stimulant with stool softening properties

Question 40

name 2 opioid receptor antagonists that are licensed for opioid induced constipation when other laxatives fail

and how do they work

Answer 40

Methylnaltrexone
Naloxegol

They are peripherally acting opioid receptor antagonists and block the constipating effects of opioids without causing central effects

Question 41

What is the carcinogen in co-danthrumer and co danthusate

Answer 41

Danton

Question 42

why should you avoid Bisacodyl and Senna at term or if Hx unstable pregnancy

Answer 42

they can simulate uterine contractions

Question 43

how much ml to add to macrogol and ispahgula husk

Answer 43

M = 100
IH = 150