1.
DRUGS FOR TREATING PEPTIC ULCERS
Drug Name Receptor or
Drug Type
Relationship MOA Uses Effects
(AE/toxicities in bold)
Sodium
Bicarbonate
(NaCO3)
Alka-Seltzer
Baking Soda
Antacid -- -Weak base that neutralises HCl
secreted in stomach
-Elevates pH which also reduces
pepsin activity
-Stimulates prostaglandin
synthesis
Short and fast acting,
5-7 doses daily
-Commonly used as over-the-counter
medication for heartburn and dyspepsia
-Provide short-term symptom relief for
peptic ulcers and GERD
(given orally)
-↑pH
-Absorbed in the gut
-Has systemic action
-Belching
-Metabolic alkalosis
(Can worsen fluid retention in patients
with heart failure, hypertension and
renal insuffiency)
Calcium
Carbonate
(CaCO3)
Tums
Antacid -- Same as above
Acts slower than NaCO3
Same as above -↑pH
-Absorbed in the gut
-Has systemic action
-Hypercalcaemia
-Belching
-Metabolic alkalosis
Aluminium
Hydroxide
(Al (OH)3)
Antacid -- Same as above Same as above -↑pH
-Poorly absorbed in the gut
-Has no systemic action
-Constipation
(negated when used with Mg (OH)2)
Magnesium
Hydroxide
(Mg (OH)2)
Antacid -- Same as above Same as above -↑pH
-Poorly absorbed in the gut
-Has no systemic action
-Osmotic diarrhoea
(negated when used with Al (OH)3)

2.
Nizatidine Histamine H2
receptor
Antagonist
(selective,
competitive,
reversible)
-Diminishes cAMP and resultant
H+/K+ pump activity
-Inhibits gastric acid secretion
-Reduces pepsin concentrations
-Inhibits histamine release from
mast cell-like cells in gastric
mucosa
-Partially inhibits meal-
stimulated acid secretion
stimulated by gastrin or vagal
stimulation
Long acting, 2x daily
(rapidly absorbed from
intestine)
-Treat uncomplicated peptic ulcers
NSAID-induced ulcers, GERD, and
Helicobacter pylori infections (when
used in combination with PPIs and 2
antibiotics) ***
(given orally)
(in elderly, uncommon)
-Headaches
-Anxiety
-Confusion
-Disorientation
(rapid infusion)
-Bradycardia
-Hypotension
Famotidine Histamine H2
receptor
Antagonist
(selective,
competitive,
reversible)
Same as above
(most potent)
Same as above Same as above
Ranitidine Histamine H2
receptor
(in parietal cells)
Antagonist
(selective,
competitive,
reversible)
Same as above Same as above Same as above
-Weak cytochrome P450 inhibitor
-Inhibit renal tubular secretion of other
drugs (e.g., propranolol,
benzodiazepines, phenytoin, warfarin)
Cimetidine Histamine H2
receptor
Antagonist
(selective,
competitive,
reversible)
Same as above Same as above
(cannot be given to pregnant women)
Same as Nizatidine
-Gynaecomastia (men)
-Galactorrhoea (women)
-↓Libido
-Impotence
-Potent cytochrome P450 inhibitor
-Inhibits renal tubular secretion, ↑
plasma conc. of other drugs

3.
Lansoprazole
Prevacid
Proton Pump
Inhibitor (PPI)
-- -Binds irreversibly to H+/K+-
ATPase (proton pump) in gastric
parietal cells
-Inhibits H+ transport
-Inhibits gastric acid secretion
Long acting, 1x daily
(P450 metabolism in liver)
-Treatment of acid reflux (GERD),
duodenal or stomach ulcers (including
those caused by NSAIDs), conditions
characterized by an overproduction of
stomach acid (such as Zollinger-Ellison
syndrome)
-Used as part of triple therapy &
quadruple therapy for Helicobacter
pylori-dependent ulcers***
(More effective than H2 antagonists)
-Generally very safe (AE not often)
-Headache
-Abdominal pain
-Diarrhoea
-Flatulence
-Nausea
-↑ gastric bacterial conc.
-↓ ketoconazole, itraconazole,
atazanavir absorption
-↑ digoxin absorption
(Long-term use)
-↓ Vitamin B-12
-↓ Calcium
- Hypergastrinemia
(↑ risk of gastric carcinoid tumours)
Rabeprazole
Aciphex
Proton Pump
Inhibitor (PPI)
-- Same as above Same as above Same as above
Esomeprazole
Nexium
Proton Pump
Inhibitor (PPI)
-- Same as above Same as above Same as above
Pantoprazole
Protonix
Proton Pump
Inhibitor (PPI)
-- Same as above Same as above Same as above
Omeprazole
Prilosec
Proton Pump
Inhibitor (PPI)
-- Same as above Same as above Same as above
-Inhibit metabolism of warfarin,
diazepam, lansoprazole
-↑ clearance of theophylline
Sucralfate Mucosal
Protective agent
-- -Complex of aluminium
hydroxide and sulphated
-Treatment of gastric and duodenal
ulcers, GERD (not caused by NSAIDs)
-Constipation

4.
sucrose that forms a viscous
paste which adheres to ulcer
bases and provides a protective
barrier
-Prevents damage to gut
mucosa by HCl, pepsin and bile
acids
-Stimulates mucosal secretion
of mucus, bicarbonate and
prostaglandins
-Reduces upper GIT bleeding
(given orally)
(less effective than H2 antagonists)
-Forms solid complexes (bezoars)
within stomach
-Aluminium toxicity in patients with
renal impairment
-↓ absorption of many drugs and food
substances
(Need acidic environment to work so
should not be administered with PPIs, H2
antagonists, or antacids)
Misoprostol
Prostaglandin
E1 analog
EP3, EP4 Agonist
(non-selective)
-Activates EP3 prostaglandin
receptors to inhibit acid and
pepsin secretion
-Mediated by Gi-mediated
inhibition of adenylate cyclase.
-Stimulates bicarbonate and
mucus secretion
-Promotes gastric ulcer healing
-Combats ulcerogenic action of
NSAIDs
-Used in treatment of duodenal and
gastric ulcers caused by NSAIDs
-Protects GIT lining from harmful
stomach acid
(Acting on EP4)
-Induces labour
-Used for abortion
-Diarrhoea
-Abdominal pain
(Acting on EP4)
-Vaginal bleeding
-Cramping
-Uterine hyperstimulation
Enprostil
Prostaglandin
E2 analog
EP3 Agonist
(selective)
Same as above -Used in treatment of duodenal and
gastric ulcers caused by NSAIDs
-Protects GIT lining from harmful
stomach acid
-Diarrhoea
-Abdominal pain
Bismuth
Subsalicylate
Pepto-Bismol
Anti-
Helicobacter
pylori agent
-- -Bind to enterotoxins, giving
them antibacterial action
against H. pylori
-Coat ulcers to reduce action of
acid and pepsin
-Increases mucous and
bicarbonate secretion
-Enhance prostaglandin
synthesis
-Used to treat traveller’s diarrhoea and
H. pylori infection associated peptic
ulcers as a second line therapy or as a
quadruple therapy ***
(given orally)
-Darkening of the tongue
-Blackened stool
-Nausea
-Vomiting
(prolonged use)
-Encephalopathy (brain damage)

5.
Short acting
(1% absorbed in systemic
circulation)
Bismuth
Subcitrate
Potassium
Anti-
Helicobacter
pylori agent
-- Same as above Same as above Same as above
Triple Therapy
Or
Quadruple
Therapy
-- -- Kills bacteria by binding to their
ribosomes to inhibit protein
synthesis
(1st
pass metabolism)
Treat peptic ulcers caused by
Helicobacter pylori infections
(given orally)
-Diarrhoea
-Nausea
Metronidazole used in place of
amoxicillin for patients allergic to
penicillin
*** Triple therapy- PPIs (once or twice daily); amoxicillin (bid) or metronidazole (bid) and clarithromycin (bid)
Quadruple therapy- PPIs or H2-anatgonist (qid or bid), bismuth subsalicylate (qid), metronidazole (qid) and tetracycline (qid).
(bid)- twice daily
(qid)- 4 times daily
GERD- gastro-oesophageal reflux disease
NSAIDs- nonsteroidal anti-inflammatory drugs

6.
DRUGS THAT CONTROL MOTILITY (ANTIDIARRHEAL AGENTS & LAXATIVES)
Drug Name Receptor or Drug
Type
Relationship MOA Uses Effects
(AE/toxicities in bold)
Codeine µ (Mu) opioid
receptors
Agonist
(selective)
-Inhibits peristalsis
-Reduces gut motility and
secretions, allowing for more fluid
absorption and more solid stools
Long acting
(P450 metabolism)
-Used to treat acute diarrhoea
Administered alone
Antidote- Naloxone (opioid antagonist)
-Safe at low doses
(At high doses)
-Drowsiness
-Nausea
-Constipation
-Abdominal cramps
-affects CNS causing analgesia,
and addiction
Diphenoxylate µ (Mu) opioid
receptors
Agonist
(selective)
Same as above Used to treat acute diarrhoea or chronic
diarrhoea associated with IBS & IBD
Administered with atropine (anti-
muscarinic) ***
Antidote- Naloxone (opioid antagonist) &
Pilocarpine (direct-acting muscarinic
agonist)
Same as above
Loperamide µ (Mu) opioid
receptors
Agonist
(selective)
Same as above
Can be used long term
-Over-the-counter drug used to treat
acute and chronic diarrhoea
Administered alone
-No tolerance to long term use
-Does not cross BBB
-No analgesia
-No potential for addiction
Kaolin Natural substituent -- Type of clay (naturally found or
made in a laboratory) that attracts
and holds onto bacteria
-Used to treat diarrhoea (in combination)
-Of late used to treat animals such as
horses, cattle, cats & dogs (rather than
humans)
-Constipation (in children &
elderly)
-Lung problems (if inhaled)
Pectin Natural substituent -- Naturally occurring polysaccharide
found in berries, apples and other
fruit
Constipation
(in children & elderly)

7.
Magnesium
Sulphate
Epsom Salts
Osmotic Laxative -- -Poorly absorbed, ↑ osmotic load
within gut lumen
-Ingested water retained and
water withdrawn from blood
stream
-Increased fluid volume promotes
movement along gut
Purgation occurs within 2h.
Bowel cleansing prior to surgery or
examination
(given orally)
Abdominal cramps
(few systemic reactions due to
low absorbance)
Macrogols Osmotic Laxative -- Same as above -Used to treat constipation
-Clear build-up of hard stool in bowel
Same as above
Sodium
Phosphate
Osmotic Laxative -- Same as above - Used to treat constipation
- Bowel cleansing prior to surgery or
examination
Same as above
Sorbitol Lactulose Osmotic Laxative -- Same as above
Used in combination as effects of
lactulose develop after 2-3 days
Same as above Same as above
Magnesium
Hydroxide
Osmotic Laxative -- Same as above -Used to treat constipation
-Used to treat peptic ulcers & GERD
-Neutralises stomach acid
-Abdominal cramps
Bisacodyl
Diphenylmethane
Derivative
Stimulant Laxative -- -Stimulates peristalsis by irritating
mucosa and/or effecting enteric
nervous system
-↑ fluid volume by promoting net
fluid secretion
Fast acting (rectal)
Slow acting (oral)
-Used to treat chronic constipation
-Bowel cleansing prior to
surgery/investigation
(given orally or rectally)
-Abdominal cramps
(used excessively)
-Tolerance to action with atony
(loss of strength) of colon
Dantron
Anthraquinones
Derivative
Stimulant Laxative -- Same as above Same as above Same as above
Senna Stimulant Laxative -- Same as above Same as above
(given orally)
Same as above

8.
Anthraquinones
Derivative
Aloe Vera Juice
Anthraquinones
Derivative
Stimulant Laxative -- Same as above Same as above
(given orally)
Same as above
Lubiprostone Chloride Secretion
activator
-- -Activates the CIC-2 chloride
channel in apical membrane of the
GI epithelium
-Enhanced secretion of chloride
ion accompanied by water leads to
↑ in intraluminal fluid
-↑ fluid content of gut, aiding
propulsive movements
(little systemic absorption)
-Chronic constipation
-IBS with constipation
(given orally)
-Nausea
-Diarrhoea
Alvimopan µ (Mu) opioid
receptor
(peripherally acting)
Antagonist
(competitive)
(selective for
GIT)
-Inhibits µ opioid receptors causing
peristalsis
-↑ gut motility and secretion
-Used to treat and prevent postoperative
ileus (intestinal obstruction)
(given orally)
-Does not cross BBB
-Dyspepsia (indigestion)
-Hypokalaemia
-Back Pain
-Delayed Micturition
(should not be given to patients
taking opioids)
Methylnaltrexone µ (Mu) opioid
receptor
(peripherally acting)
Antagonist
(competitive)
(selective)
Same as above -Used to treat opioid induced
constipation (when other laxatives have
failed)
(given orally, IV, SC)
-Does not cross BBB
-Dyspepsia (indigestion)
-Hypokalaemia
-Back Pain
-Delayed Micturition
-↑ pain from inflammatory
conditions (e.g., arthritis)
(should not be given to patients
taking opioids for analgesia)

9.
Prucalopride 5-HT4 (serotonin)
receptor
Agonist
(selective)
-Activates 5-HT4 receptor
stimulating 2nd
order enteric
neurons to promote peristalsis
-↑ number of bowel movements
Used to treat chronic constipation
(given orally)
-Headache
-Abdominal pain
-Nausea
-Diarrhoea
Tegaserod 5-HT1, 5-HT2, 5-HT4 Agonist
(non-
selective)
Same as above Used to treat IBS with constipation
(given orally)
(Was removed for use from the FDA in
2007 but recently reintroduced in 2019
for women under 65)
-Headache
-Abdominal pain
-Nausea
-Diarrhoea
-Dizziness
-Migraine
-Back pain
-Joint pain
Vomiting
-Bloating
-Leg pain
-Fatigue
Docusate Faecal Softener -- -Surfactant with emulsifying action
-Softens/lubricates stool to allow
easier passage along gut and
defaecation
Used to treat constipation and
haemorrhoids
(given orally or rectally)
-Well tolerated
-Abdominal cramping
Arachis Oil Faecal Softener -- Same as above Same as above
(given rectally)
Same as above
Liquid Paraffin Faecal Softener -- Same as above Used to treat chronic childhood
constipation
(given orally or topically)
-Well tolerated
-Abdominal cramping
-Impair absorption of fat-soluble
vitamins
Methylcellulose Bulk laxative -- -Poorly absorbed but hygroscopic
(absorbs moisture)
-↑ amount of water in stool
-Forms soft faecal mass which
distends gut to promote peristalsis
Slow acting
-Used to treat constipation
-Used if increasing dietary fibre is
inadequate
-Prevent intestinal obstruction
(given orally)
-Flatulence
-Obstruction
(Few systemic actions due to
low absorption)

10.
Ispaghula Husk Bulk laxative -- Same as above Same as above Same as above
Sterculia Bulk laxative -- Same as above Same as above Same as above
*** Other anti-cholinergic muscarinic drugs similar to atropine have anti-diarrheal effects but are not used as anti-diarrheal agents as they affect other
parts of the body (i.e., have a lot of side effects) See table or notes on Cholinergic Drugs for full side effects
IBS- irritable bowel syndrome
IBD- inflammatory bowel disease
BBB- blood brain barrier
IV- intravenously
SC- subcutaneously

11.
DRUGS USED TO TREAT VOMITTING & NAUSEA (ANTIEMITICS)
Drug Name Receptor or Drug
Type
Relationship MOA Uses Effects
(AE/toxicities in bold)
Chlorpromazine Dopamine D2-
receptor
Antagonist
(Reversible)
(Competitive)
-Inhibits dopamine D2 receptors in
CTZ ***
-Inhibits cholinergic smooth muscle
stimulation in the GIT
(P450 metabolism)
-Used to treat nausea and vomiting
associated with cancer chemotherapy,
radiation therapy and general anaesthesia
-Used to treat documented GERD in patients
who fail to respond to conventional therapy
(given orally)
(cannot be given to patients with
Parkinson’s or seizure diseases)
-↓ heartburn
-Sedation
-Hypotension
-Galactorrhoea (from prolactin
release)
-Has antihistamine &
antimuscarinic actions (dry mouth,
antidiarrheal, etc)
-Has extrapyramidal effects (i.e.,
Parkinsonian symptoms) ***
Prochlorperazine Dopamine D2-
receptor
Antagonist
(Reversible)
(Competitive)
Same as above Same as above Same as above
Thiethylperazine Dopamine D2-
receptor
Antagonist
(Reversible)
(Competitive)
Same as above Same as above Same as above
Metoclopramide Dopamine D2-
receptor
Antagonist
(Reversible)
(Competitive)
Same as above Same as above Same as above
Domperidone Dopamine D2-
receptor
Antagonist
(Reversible)
(Competitive)
Same as above Prevents nausea, vomiting caused by other
drugs used to treat Parkinson's Disease
-↓ heartburn
-Sedation
-Hypotension
-Galactorrhoea (from prolactin
release)
-Has antihistamine &
antimuscarinic actions (dry mouth,
antidiarrheal, etc)

12.
Ondansetron 5-HT3-receptor Antagonist
(reversible)
(competitive)
Inhibits 5-HT3 receptors in CTZ and
at the sensory endings of vagal
afferents in GIT
(P450 metabolism)
-Used to treat nausea and vomiting caused
by cytotoxic, anticancer drugs, and arising
postoperatively or after radiation treatment
-Often given a short time before starting
chemotherapy
-Limited effectiveness in motion sickness
(given orally)
-Well tolerated
-Headache
-GIT upsets (abdominal pain, etc)
Granisetron 5-HT3-receptor Antagonist
(reversible)
(competitive)
Same as above Same as above Same as above
Dolasetron 5-HT3-receptor Antagonist
(reversible)
(competitive)
Same as above Same as above Same as above
Tropisetron 5-HT3-receptor Antagonist
(reversible)
(competitive)
Same as above Same as above Same as above
Scopolamine
Hyoscine
Muscarinic
receptor
Antagonist
(reversible)
(competitive)
Inhibits muscarinic receptors
including those in vestibular
nucleus and vomiting centre,
causing antiemetic effects
Long acting (transdermal patch)
-Tends to be given prophylactically
(preventative) against motion sickness
-Effective against local gut stimuli
-Not effective against chemotherapy-induced
emesis mediated via the CTZ
(given orally or transdermal patch)
Cannot be used in closed-angle glaucoma
-Drowsiness
-Amnesia
(anti-muscarinic effects)
-Dry mouth
-Tachycardia
-Blurred vision
-Urinary retention
See table or notes on Cholinergic
Drugs for full side effects
Promethazine Histamine H1-
receptor
Antagonist
(reversible)
(competitive)
Inhibits H1 receptors including
those in vestibular nuclei and
‘vomiting centre’ causing
antiemetic effects
(1st
pass metabolism)
Used to treat motion sickness and other
emesis of vestibular origin (e.g., Meniere’s
disease), vomiting in early pregnancy, and
emesis due to local stimuli in gut acting via
vagus.
-Sedative
-Confusion (in elderly)
-Dry mouth (anticholinergic action)
-Depression (in infants under 2)

13.
Meclizine Histamine H1-
receptor
Antagonist
(reversible)
(competitive)
Same as above Same as above Same as above
Dimenhydrinate
Gravol
Histamine H1-
receptor
Antagonist
(reversible)
(competitive)
Same as above Same as above Same as above
Less sedating
Cyclizine Histamine H1-
receptor
Antagonist
(reversible)
(competitive)
Same as above Same as above Same as above
Less sedating
Cinnarizine Histamine H1-
receptor
Antagonist
(reversible)
(competitive)
Same as above Same as above Same as above
Less sedating
***
CTZ- chemoreceptor trigger zone (area of the medulla oblongata that receives inputs from blood-borne drugs or hormones, and communicates with other
structures in the vomiting centre to initiate vomiting)
Extrapyramidal refers to the part of the motor system network (motor control & coordination) that causes involuntary actions