GI V: motility and inflammatory bowel disease Flashcards
Drugs used to relieve constipation
1st line–> Bulk laxatives (methylcellulose)
2nd line –> osmostic laxatives (Mg hydroxide, Sodium citrate)
3rd line –> Stimulant laxatives (Senna)
Osmotic laxatives Examples
Mg Sulfate
Mg hydroxide
Sodium citrate
Sodium Phosphate
Lactulose
Macrogols
MoA of Osmotic laxatives
Provides osmotic load to draw water into GI lumen –> traps increased volumes of fluid in the lumen of the bowel –> accelerate the transfer of the gut contents through the small intestine.
* Distension in colon and purgation within 1h
Clinical uses of Magensium sulfate/ Mg hydroxide
2nd line tx of constipation
they are Saline purgatives→ poorly absorbed
solutes. Mg absorbed is too small to have adverse effects
AE of Osmotic laxatives
1) Heart block,
2) neuromuscular block or CNS depression.
3) Abdominal cramps.
Contraindication of Osmotic laxatives
In Small kids and
poor renal function
Bulk laxatives Examples
Methylcellulose
Sterculia
Agar
Bran
Ispaghula husk
Psyllium
Clinical uses of Methylcellulose and Psyllium
1st line anti-constipation drugs
* May take a few days to work
* slow-acting
* Bulk laxatives
AE of Bulk laxatives
Bloating
* no serious AE
MoA of Bulk laxatives
soluble fibers that draw water into gut lumen, forming viscous liquid (bulky hydrated mass) that promotes peristalsis
Clinical uses of Lactulose
1) Relives constipation
2) tx of hepatic encephalopathy
AE of Lactulose
1) Flatulence (“passing wind”),
2) cramps,
3) diarrhoea,
4) electrolyte disturbance.
Stimulant laxatives examples
Bisacodyl
Glycerol
Senna
Dantron
*Great Bella Sees Delusions
MoA of Senna/ Bisacodyl
Enteric nerve stimulation –> colonic contraction (increases peristalsis)
* Stimulant laxatives
Clinical uses of Senna/ Bisacodyl
3rd line anti-constipation tx
* Stimulant laxatives
AE of Stimulant laxatives
1) Abdominal cramps and
2) melanosis coli - caused by lon-term tx esp. Senna (deposition of brown/black pigment in the colorectal mucosa)
Stool softener examples
Docusate sodium
Arachis oil
Liquid paraffin
why are laxatives preferred over stool softeners in the tx of Constipation?
laxatives increase motility in the GI tract unlike stool softners, which only soften stool
D2 receptor antagonists (Prokinetic) used in the tx of constipation
Metoclopramide
Domperidone
Clinical uses of Metoclopramide and
Domperidone
1) GOERD
2) Gastroparesis (paralysis of the stomach -> slows digestion)
3) Anti-emesis
* D2 receptor antagonists
MoA of Metoclopramide
Domperidone
D2 receptor antagonists –> increases motility in the lower oesophageal sphincter and duodenum
4th line tx of constipation?
Prucalopride - selective HT-4 receptor agonist (prokinetic)
AE of Prucalopride
Ab cramps,less appetite, diarrhoea, dizziness, dyspepsia, fatigue, flatulence, headache, nausea, polyuria, rectal bleeding, vomiting
Anti-diarrheal agents?
1) Opiates (Codeine, Loperamide)
2) Anti-cholinergics (Atropine, Hyoscine)
Which Opiate is more preferred in the tx of diarrhea, Codein or Loperamide . Explain
Loperamide –> not Addictive
Codeine acts on the CNS unlike Loperamide which acts on the PNS, meaning that it does not cross the BBB and therefor is not addictive like Codeine
- Codeine is addictive if used for > 7 days
AE of Opiates
*Codeine, Loperamide
1) Sedation
2) Dizziness
3) dry mouth
4) nausea
5) Constipation
6) Vomiting
7) ab cramps
8) mioses ( pupil constriction- “pin-point pupil)
AE of anti-cholinergics (muscarinics)
*Hyoscine , Atropine
1) Mydriasis (pupil dilation )
2) Dry mouth
3) blurred vission
4) urinary retetion
5) constipation
6) Tachycardia
Drugs used in the tx of inflamatory bowel disease (IBD)
1) Glucocorticoids (Prednison) –> Chron’s
2) Aminocalycilate (Sulfasalazine)–> Ulcerative colitis
clinical uses of Methotrexate and Azathioprine
Long-term managment of IBD (reduce the long-term need for steroids)
MoA of Azathioprine and 6-mercapto-purine
Inhibits Purine synthesis –> reduces inflammation
1st line tx of Chron’s disease
Glucocortcoids
Prednisone/ Budesonide
* reduce inflammation
1st line tx of Ulcerative colitis
Aminosalicylates (5-ASAS)
1) Sulfasalazine
2) Olsalazine
3) Balsalazide
-salazin/d
CU of Sulfasalazine
* 5-ASA
Ulcerative colitis
AE of Sulfasalazine
1) Diarrhoea,
2) salicylate sensitivity,
3) interstitial nephritis (monitor kidney
function - GFR),
4) decreases number and motility of sperm (reversible)
Alternative drugs used in the tx of IBD when pateints are unresponsive to other treatments (steroids/ 5-ASAs)
Infliximab/Adalimumab
(TNF-a inhibitors)
