Drugs used for treatment of GI motility disorders Flashcards
Domperidone
ANTIMIMETIC
MOA: blocks D2 receptors in chemoreceptor trigger zone
- loss of myenteric motor neuron inhibition –> Ach release
stimulates gut motor function
-increase esophageal peristalsis
-increase lower esophageal sphincter pressure
-enhance gastric emptying
Metoclopramide
ANTIMIMETIC
MOA: blocks D2 receptors in chemoreceptor trigger zone
- loss of myenteric motor neuron inhibition –> Ach release
stimulates gut motor function
-increase esophageal peristalsis
-increase lower esophageal sphincter pressure
-enhance gastric emptying
has more adverse effects than domperidone
Ondansetron
ANTIMIMETIC
MOA: blocks 5HT3 receptors in
- vomiting centre
- extrinsic intestinal vagal and spinal afferent nerves
Drug of choice for chemotherapy (prevents emesis)
Dexamethasone (corticosteroid)
- increases efficacy of 5HT3 antagonists
Aprepitant
ANTIMIMETIC
MOA: block neurokinin receptors in area postrema
used for chemotherapy emesis (in combo with 5HT3 antagonists and corticosteroids)
Scopolamine
ANTIMIMETIC
treats motion sickness
- anticholinergic
Cyclizine
ANTIMIMETIC
- antihistamine
treats motion sickness in pregnancy
Betanachol
ANTIMIMETIC
MOA: stimulates M3 receptors
-increases gastric secretion
Neostigmine
ANTIMIMETIC
MOA: binds to acetylcholinesterase, increases Ach
- increases gastric secretion, small intestine and colonic emptying
Cisapride
ANTIMIMETIC
MOA: 5HT4 agonist
- promotes release of Ach from myenteric plexus
5HT3 antagonist
Treats GERD
Tegaserod
ANTIMIMETIC
MOA: partial 5HT4 agonist
treats constipation predominant in IBS
Bran
CONSTIPATION DRUG
BULK FORMING LAXATIVE
MOA: soluble fibres increase water absorption in lumen
- increases fecal mass (stretches bowel wall) –> stimulates peristalsis
treats constipation
Psyllium
CONSTIPATION DRUG
BULK FORMING LAXATIVE
MOA: soluble fibres increase water absorption in lumen
- increases fecal mass (stretches bowel wall) –> stimulates peristalsis
treats constipation
Ispaghula
CONSTIPATION DRUG
BULK FORMING LAXATIVE
MOA: soluble fibres increase water absorption in lumen
- increases fecal mass (stretches bowel wall) –> stimulates peristalsis
treats constipation
Docusates
CONSTIPATION DRUG
STOOL SOFTENERS
MOA: anionic surfactants, decreases stool tension
- emulsifies colonic contents, increases penetration of water in feces
Treats constipation
Liquid Paraffin
CONSTIPATION DRUG
STOOL SOFTENERS
MOA: anionic surfactants, decreases stool tension
- emulsifies colonic contents, increases penetration of water in feces
Treats constipation
Bisacodyl
CONSTIPATION DRUG
STIMULANT LAXATIVES
MOA: water and electrolyte retention in lumen
- alters absorptive and secretory activity of mucosal cells, irritates intestinal mucosa (stimulates motor activity) –> acts on myenteric plexus
treats constipation
Senna
CONSTIPATION DRUG
STIMULANT LAXATIVES
MOA: water and electrolyte retention in lumen
- alters absorptive and secretory activity of mucosal cells, irritates intestinal mucosa (stimulates motor activity) –> acts on myenteric plexus
treats constipation
Castor oil
CONSTIPATION DRUG
STIMULANT LAXATIVES
MOA: water and electrolyte retention in lumen
- alters absorptive and secretory activity of mucosal cells, irritates intestinal mucosa (stimulates motor activity) –> acts on myenteric plexus
treats constipation
Magnesium salts
CONSTIPATION DRUG
OSMOTIC LAXATIVES
MOA: on small and large intestines
- increases osmotic pressure, draws water into lumen
- retention of water causes peristalsis
- releases CCK, increasing intestinal secretions and peristalsis
SODIUM SALTS
CONSTIPATION DRUG
OSMOTIC LAXATIVES
MOA: on small and large intestines
- increase osmotic pressure, draw water into lumen, which causes peristalsis
Lactulose
CONSTIPATION DRUG
OSMOTIC LAXATIVES
MOA: retains water
drug is not absorbed or digested in small intestine (increases osmotic pressure)
- is broken down in colon by bacteria
Loperamide
DIARRHEA DRUG
OPIOID
MOA: activates presynaptic opioid receptors in enteric nervous system
- inhibits Ach release
- decreases peristalsis
- enhances absorption
Does not cross BBB
used in non-infective diarrhea, mild travelers diarrhea
NOT used in infective diarrhea, young children, severe colitis patients
Dicyclomine
DIARRHEA DRUG
ANTIMUSCARINIC, ANTISPASMODIC
MOA: relaxation of smooth muscle of GIT
- reduces spasm, relieves pain
Zinc
reduces fluid secretion in intestine
strengthens immune response
aids in regeneration of intestinal epithelium
