GI drugs Flashcards
Disorder involving erosion or ulceration of mucosal lining of GI tract
Acid Peptic Disease
Drug that reduces nausea and vomiting
Anti emetics
Esophageal irritation or inflammation due to reflux of stomach acid
GERD
Paralysis of muscle of stomach and GI due to nerve or muscle damage
Common in DM and PD
Gastroparesis
Inflammatory disease involving irritation and ulceration of COLON and RECTUM
Ulcerative colitis
Inflammatory disorder involving colon plus proximal parts of GI tract
Crohn’s dse
Disease of unknown origin manifesting as episodes of abdominal discomfort and abnormal bowel dysfunction
Irritable bowel syndrome
Drug that promotes GI motility
Prokinetic
Uses energy of ATP to secrete protons into stomach
Common target of drugs that suppress acid secretion
Proton Pump H/K ATPase in Parietal Cell
Weak bases that neutralize stomach acid by reacting with protons in the lumen
Antacids
PROTECTIVE FUNCTION of gastric mucosa
Antacids
Difference in antacids
Absorption and stool consistency
Aluminum hydroxide causes
Constipation
Magnesium hydroxide causes
Diarrhea
Less commonly used bec are completely absorbed and with more SE
Sodium bicarbonate Calcium carbonate
Two classes of GI drugs
1 reduce intragastric acidity
2 promote mucosal defense
Inhibit basal acid production by parietal cells
Inhibits binding of histamine at H2 receptor and preventing HKATPase pump
H2 antagonist
Cimetidine
Ranitidine
Famotidine
Nizatidine
Inhibit prandial acid release
H2 agonist
Cimetidine
1st H2 blocker
CYP450 inhibitor (inc Warfarin effect)
Inc metabolism of estrodiol - gynecomastia
Cimetidine endocrine effects (4)
Alopecia
Loss of libido
Impotence
Irregular menstruation
Most used H2 receptor blocker
Ranitidine
H2 receptor blocker other SE
Abdominal discomfort
NDV
Give BID PO
Proton Pump Inhibitors are Lipophilic weak bases that irreversibly inactivate the final common pathway of H secretion
H+/K+ ATPase
PPIs are metabolized in the
And have a half life of
Liver
1-2h
PPIs have a duration of action of
and
Require days of treatment to achieve effectiveness
24 h
3-4 days of treatmenr
Most bioavailable of PPIs
Lansoprazole
Lansoprazole is excreted via
the rest are via renal
biliary tract
PPIs can inhibit percentage of 24h acid secretion
SE
90-98%
C difficile Pneumonia Dec absorption of Ca, Mg and Fe cations Osteoporosis (dec Ca absorption) Hypomagnesemia
Least bioavailable PPI
Omeprazole
PGE analog increasing mucus and bicarbonate
Misoprostol
Misoprostol increases
and inhibits
mucosal protection
acid secretion
Misoprostol CI
pregnant
Sucrose complex with sulfatef aluminum hydroxide
Sucralfate
Sucralfate MOA
polymerizes in acid environment of stomach
Sucralfate SE
constipation
Reduces stool frequency and liquidity in infectious diarrhea
Bismuth salt
Bismuth SE
stool and tongue blackening
Bismuth toxicity (5)
Encephalopathy Ataxia Headache Confusion Seizure
D2 antagonist that can cross BBB and has antiemetic effect at CTZ
Metaclopromide
Metaclopromide SE
EPS and endocrine
Does not cross BBB, not anti enetic but for stimulation of Post Partum Lactation
Domperidone
Macrolide that promotes Motilin release
Erythromycin Parenteral
Erythromycin se
Diarrhea
Used in constipation, prevention of straining, preparation of diagnostic examination, removal of poison or toxin, antihelminth
Laxative
Laxatives are CI in
Appendicitis
Diverticulitis
Ulcerative colitis
Laxative SE
Diarrhea Abdominal cramping Nausea Fluid and electrolyte imbalance Sympathetic reactions CATHARTIC dependence
Surfactant which facilitate mixing of water and oily material
Stool softeners/Emollients
Drugs with 5 aminisalicylic acid (5-ASA) for topical therapy in IBD
These inhibit synthesis of prostaglandin and inflammatory leukotrienes hence no cytokines
Aminosalicylate
Inhibits cAMP and blocks cytosol Ca
Inhibits GH, glucagon, insulin, gastrin
Used in treatment of esophageal varices, acromegaly, carcinoid, glucagonoma, gastrinoma)
Somatostatin
Long acting somatostatin synthetic analog
Acromegaly, carcinoid, gastrinoma, glucagonoma
Ocreotide
Ocreotide side effects
GI
gallstones
Bradycardia, conduction anomaly
Agonist at V1 and V2 ADH
Activates insertion of aquaporin in water channels in collecting tubule
Decreases water excretion
Vasoconstriction
Used for varices, pituitary diabetes insipidus
Desmopressin
Vasopressin
Desmopressin
Vasopressin
side effect
Hyponatremia
Hypertension
Promotility agents
Erythromycin 250
Metaclopromide D2 antagonist 10
Domperidone D2 antagonist
D2 dompamine receptor antagonist against area postrema but
Prokinetic promoting upper GI intestinal motility
D2 receptor blocking action in the area postrema of value in preventing emesis after surgical anesthesia and cancer chemotherapeutic drugs
Metaclopromide
Domperidone
Metaclopromide SE
Parkinsonism EPS Tardive dyskinesia Hyperprolactinemia Upper GI prokinetic Diarrhea because of D2 receptor blockade Drowsiness Depression Neuroleptic malignant syndrome bec of D2 blockade (fever, rigidity, msc, autonomic instability, rhabdomyolysis) QT prolongation Torsade de pointes
D2 antagonist that does not cross BBB so less CNS
Domperidone
Promotes motility by stimulating motilin receptors
Erythromycin
Interferes with activity of T lymphocytes , decreased inflammation
Metabolized to sulfapyridine and 5 ASA
Compete with p-aminobenzoic acid (PABA)
Inhibits dihydropteroate synthase
Sulfasalazine
Calcineurin inhibitor
Inhibits trascription of IL - 2 and cytokines involved in T cell activation
Used in severe UC refractory to IV corticosteroids
Cyclosporine
Activates u opiod receptor and slows motility with negligible CNS effects
Loperamide
Similar:
Diphenoxylate greater CNS opiod
5HT3 receptor antagonist of high potency and duration of binding
Reduces smooth muscle activity in GI tract
Severe diarrhea predominant IBS in women
Alosetron
Alosetrone 5HT3 antagonist SE
ischemic colitis
bowel infarct
constipation
Chloride channel activator useful in constipation-predominant IBS
Lubiprostone
Selective 5HT3 receptor block on vagal afferents of GI and CNS
Prevention of chemotherapy-induced and postoperative nausea and vomiting
May slow colonic transit
constipation
Ondansetron
similar:
Dolasetron
Granisetron
Palonosetron
GI irritation due to infection, chemotherapy and distention cause release of
serotonin activating 5HT3 receptors of vagus nerve relaying impulse at vomiting centers hence emesis
Vestibular system also communicates directly to vomiting center hence
vestibular nausea
5HT3 antagonists like ondansentron alarming SE
Prolong QT interval Torsade Serotonin syndrome (rigidity, tremor, hyperthermia and confusion)
Vestibular system receptors for vomiting and emesis
H1 histamine receptor coupled to Gq
M1 muscarinic receptors
Treat vestibular nausea and motion sickness
1st gen antihistamine receptors
Diphenhydramine
Meclizine
SE: sedation, antimuscarinic
Muscarinic agonist that treats motion sickness (M1 blockade)
Scopolamine
Area postrema receptors
D2 receptors
Neurokinin NK1 receptors activated by Substance P
Metaclopromide CI
Small bowel obstruction
Antagonizes NK1 receptors in area postrema
Treats chemotherapy induced vomiting
No effect on serotonin, dopamine and muscarinic receptors
Limited adverse effects
Aprepitant
Inhibits both gastrin and histamine by ECL cells
Tones down gastric acid production even on gastrinomas
Somatostatin
Ocreotide long acting SST analog useful on Zollinger Ellison
