THE UNIVERSITY OF
WESTERN
AUSTRALIA
DENT 3005:Introduction to
Pharmacology
**Gastrointestinal drugs**
Dr Thuy Linh Truong
thuy.truong@uwa.edu.au
# **DENT 3005: Introduction to Pharmacology**
## **Gastrointestinal drugs**
**Dr Thuy Linh Truong**
thuy.truong@uwa.edu.au
**Acknowledgement**
of country
<img class="image-with-labels" src="image.png" alt="A black and white abstract artwork depicting indigenous patterns, associated with a land acknowledgement text.">
The University of Western Australia acknowledges that its campus is situated on Noongar land, and that Noongar people remain the spiritual and cultural custodians of their land, and continue to practise their values, languages, beliefs and knowledge.
Artist: Dr Richard Barry Walley OAM
# **Acknowledgement of country**
The University of Western Australia acknowledges that its campus is situated on Noongar land, and that Noongar people remain the spiritual and cultural custodians of their land, and continue to practise their values, languages, beliefs and knowledge.
Artist: Dr Richard Barry Walley OAM
**Learning Outcomes**
Learning objectives
1) Understand the classes and mechanisms of major classes of GI drugs
2) Recognise common GI conditions managed with these drugs
3) Recognise oral and dental side effects of GI drugs
4) Understand the oral impact of GI conditions
5) Understand drugs interactions with dental medications
6) Applied knowledge to clinical scenarios
![]()
A variety of icons representing gastrointestinal conditions and related concepts.
# **Learning Outcomes**
## **Learning objectives**
1) Understand the classes and mechanisms of major classes of GI drugs
2) Recognise common GI conditions managed with these drugs
3) Recognise oral and dental side effects of GI drugs
4) Understand the oral impact of GI conditions
5) Understand drugs interactions with dental medications
6) Applied knowledge to clinical scenarios
**Gastrointestinal drugs**
* Ulcers
* Dyspepsia: chronic/recurrent pain, burning or discomfort centered in upper abdomen
* GORD: chronic & relapsing condition
* PUD: H-pylori most common cause, others medication induced
* Drug therapy: Antacids, H2 antagonists, PPIs, other drugs for ulcer
* Laxatives
* Anti-emetics
* Anti-diarrheal
* Inflammatory bowel disease
* Obesity
* Perianal disorder
# **Gastrointestinal drugs**
- **Ulcers**
- Dyspepsia: chronic/recurrent pain, burning or discomfort centered in upper abdomen
- GORD: chronic & relapsing condition
- PUD: H-pylori most common cause, others medication induced
- Drug therapy: Antacids, H2 antagonists, PPIs, other drugs for ulcer
- **Laxatives**
- **Anti-emetics**
- **Anti-diarrheal**
- **Inflammatory bowel disease**
- **Obesity**
- **Perianal disorder**
**Antacids**
* MOA: neutralize hydrochloric acid secreted by
gastric parietal cells
* Dental implications: nil
* Drug interaction: reduce absorption of many
drugs
**H₂ antagonists**
* MOA: competitively block H2 receptors on
parietal cells, Reduce gastric acid secretion
* Dental implication: dry mouth, taste disorder
* Drug interaction: reduce absorption of azoles
| Generic name | Brand Name |
| :--- | :--- |
| Aluminum hydroxide | Alu-tab |
| Combo antacids | Mylanta, Rennie |
| Generic name | Brand Name |
| :--- | :--- |
| Famotidine | Ausfam, Pepzan |
| Nizatidine | Nizac, Tazac |
| Ranitidine | Ausran, Rani |
# **Ulcer Medications**
## **Antacids**
- **MOA:** neutralize hydrochloric acid secreted by gastric parietal cells
- **Dental implications:** nil
- **Drug interaction:** reduce absorption of many drugs
| Generic name | Brand Name |
| :--- | :--- |
| Aluminum hydroxide | Alu-tab |
| Combo antacids | Mylanta, Rennie |
## **H₂ antagonists**
- **MOA:** competitively block H2 receptors on parietal cells, Reduce gastric acid secretion
- **Dental implication:** dry mouth, taste disorder
- **Drug interaction:** reduce absorption of azoles
| Generic name | Brand Name |
| :--- | :--- |
| Famotidine | Ausfam, Pepzan |
| Nizatidine | Nizac, Tazac |
| Ranitidine | Ausran, Rani |
**Proton Pump Inhibitors**
* **MOA:** irreversibly inactivate proton pump
* Suppress stimulated & basal acid secretion
* **Dental implications:** dry mouth, taste disturbance
* Implant failure???
* **Drug interaction:** reduce absorption of azoles
| Generic name | Brand Name |
| :--- | :--- |
| **Esomeprazole** | **Nexium** |
| **Lansoprazole** | **Zopral, Zoton** |
| **Omeprazole** | **Acimax, Losec** |
| **Pantoprazole** | **Somac** |
| **Rabeprazole** | **Pariet** |
**Other drugs for ulcers**
* Bismuth subcitrate & sucralfate
* **MOA:** forms acid & pepsin resistant coating at ulcer site
* [Bismuth Sub] **ADR:** darkening of teeth & tongue
* [Sucralfate]: Dry mouth
* Misoprostol
* Prostaglandin E analogue: increase mucus secretion in stomach
| Generic name | Brand Name |
| :--- | :--- |
| **Bismuth subcitrate** | **Bismuth subcitrate** |
| **Sucralfate** | **Ulcyte** |
| **Misoprostol** | **Cytotec** |
## **Proton Pump Inhibitors**
- **MOA:** irreversibly inactivate proton pump
- Suppress stimulated & basal acid secretion
- **Dental implications:** dry mouth, taste disturbance
- Implant failure???
- **Drug interaction:** reduce absorption of azoles
| Generic name | Brand Name |
| :--- | :--- |
| **Esomeprazole** | **Nexium** |
| **Lansoprazole** | **Zopral, Zoton** |
| **Omeprazole** | **Acimax, Losec** |
| **Pantoprazole** | **Somac** |
| **Rabeprazole** | **Pariet** |
## **Other drugs for ulcers**
- **Bismuth subcitrate & sucralfate**
- **MOA:** forms acid & pepsin resistant coating at ulcer site
- [Bismuth Sub] **ADR:** darkening of teeth & tongue
- [Sucralfate]: Dry mouth
- **Misoprostol**
- Prostaglandin E analogue: increase mucus secretion in stomach
| Generic name | Brand Name |
| :--- | :--- |
| **Bismuth subcitrate** | **Bismuth subcitrate** |
| **Sucralfate** | **Ulcyte** |
| **Misoprostol** | **Cytotec** |
Here is the text extraction and formatting:
```mermaid
flowchart TD
G(G cell)
ECL(ECL cell)
P(PARIETAL CELL)
AA(AA)
PGE2(PGE₂)
HIST(Histamine)
GASTRIN(Gastrin)
SST({{Somatostatin}})
NS(NSAIDs)
MISO(Misoprostol)
H2B(H₂ blockers)
PPI(Proton pump inhibitors)
ATRO(Atropine)
ACH(Ach)
G -- Gastrin --> ECL;
SST --|Inhibits| G;
SST --|Inhibits| ECL;
SST --|Inhibits| P;
GASTRIN --> ECL;
ECL -- Histamine --> P;
AA -->|Inhibited by| NS;
AA --> PGE2;
PGE2 --|Stimulates| ECL;
MISO --|Stimulates| ECL;
HIST --> P;
H2B --|Inhibits| P;
ACH --> P;
ATRO --|Inhibits| P;
PPI --|Inhibits| P;
subgraph Receptors
SST_R_G[SST₂R]
CCK_R_ECL[CCK₂R]
SST_R_ECL[SST₂R]
EP_23_R[EP₂/₃R]
H2_R[H₂R]
SST_R_P[SST₂R]
CCK_R_P[CCK₂R?]
M3_R[M₃R]
end
G --> SST_R_G;
GASTRIN --> CCK_R_ECL;
SST --> SST_R_G;
SST --> SST_R_ECL;
SST --> SST_R_P;
PGE2 --> EP_23_R;
MISO --> EP_23_R;
HIST --> H2_R;
H2B --> H2_R;
GASTRIN --> CCK_R_P;
ACH --> M3_R;
ATRO --> M3_R;
P -- "H⁺" --> PPI;
P -- "K⁺" --> PPI;
P -- "Cl⁻" --> PPI;
P -- "H⁺" --> H_out;
P -- "K⁺" --> K_out;
P -- "Cl⁻" --> Cl_out;
```
* Located in gastric antrum of stomach and duodenum
* Produce and secrete gastrin- secretes gastric acid secretion
* Gastrin stimulates parietal cells to secrete HCl
* **Located in gastric mucosa**
* **Secrete histamine – stimulates parietal cells to produce HCl**
* **Histamine released by ECL binds to the H2 receptor on parietal cells enhancing acid secretion**
* Located in gastric mucosa
* Responsible for secreting HCl and intrinsic factor
* HCl – creates an acidic environment – for protein digestion/ activation of digestive enzymes.
* Intrinsic factor- for vitamin B12 absorption in small intestine
**G cell**
Gastrin
**ECL cell**
Somatostatin
Histamine
**PARIETAL CELL**
H⁺
K⁺
Cl⁻
H⁺
K⁺
Cl⁻
**NSAIDs**
**Misoprostol**
**H₂ blockers**
Ach
**Atropine**
**Proton pump inhibitors**
AA
PGE₂
# **Mechanism of Gastric Acid Secretion**
```mermaid
flowchart TD
G(G cell)
ECL(ECL cell)
P(PARIETAL CELL)
AA(AA)
PGE2(PGE₂)
HIST(Histamine)
GASTRIN(Gastrin)
SST({{Somatostatin}})
NS(NSAIDs)
MISO(Misoprostol)
H2B(H₂ blockers)
PPI(Proton pump inhibitors)
ATRO(Atropine)
ACH(Ach)
G -- Gastrin --> ECL;
SST --|Inhibits| G;
SST --|Inhibits| ECL;
SST --|Inhibits| P;
GASTRIN --> ECL;
ECL -- Histamine --> P;
AA -->|Inhibited by| NS;
AA --> PGE2;
PGE2 --|Stimulates| ECL;
MISO --|Stimulates| ECL;
HIST --> P;
H2B --|Inhibits| P;
ACH --> P;
ATRO --|Inhibits| P;
PPI --|Inhibits| P;
subgraph Receptors
SST_R_G[SST₂R]
CCK_R_ECL[CCK₂R]
SST_R_ECL[SST₂R]
EP_23_R[EP₂/₃R]
H2_R[H₂R]
SST_R_P[SST₂R]
CCK_R_P[CCK₂R?]
M3_R[M₃R]
end
G --> SST_R_G;
GASTRIN --> CCK_R_ECL;
SST --> SST_R_G;
SST --> SST_R_ECL;
SST --> SST_R_P;
PGE2 --> EP_23_R;
MISO --> EP_23_R;
HIST --> H2_R;
H2B --> H2_R;
GASTRIN --> CCK_R_P;
ACH --> M3_R;
ATRO --> M3_R;
P -- "H⁺" --> PPI;
P -- "K⁺" --> PPI;
P -- "Cl⁻" --> PPI;
P -- "H⁺" --> H_out;
P -- "K⁺" --> K_out;
P -- "Cl⁻" --> Cl_out;
```
## **Cell Functions and Drug Targets**
### **G cell**
- Located in gastric antrum of stomach and duodenum
- Produce and secrete gastrin- secretes gastric acid secretion
- Gastrin stimulates parietal cells to secrete HCl
- **Target for:** Gastrin, Somatostatin
### **ECL cell**
- **Located in gastric mucosa**
- **Secrete histamine – stimulates parietal cells to produce HCl**
- **Histamine released by ECL binds to the H2 receptor on parietal cells enhancing acid secretion**
- **Target for:** Histamine, Somatostatin
### **PARIETAL CELL**
- Located in gastric mucosa
- Responsible for secreting HCl and intrinsic factor
- HCl – creates an acidic environment – for protein digestion/ activation of digestive enzymes.
- Intrinsic factor- for vitamin B12 absorption in small intestine
- **Secretes:** H⁺, K⁺, Cl⁻
- **Target for:** H₂ blockers, Atropine, Proton pump inhibitors
### **Other Components**
- **NSAIDs:** Inhibit AA
- **Misoprostol:** Stimulates ECL
- **Ach:** Stimulates Parietal Cell
- **AA:** Precursor to PGE₂
- **PGE₂:** Stimulates ECL
The image displays two figures side-by-side: a diagram illustrating the regulation of stomach acid production and the mechanism of a proton pump inhibitor (PPI), and a diagram of the stomach with labels indicating different medications used to treat stomach-related conditions and their mechanisms of action.
On the left:
```mermaid
flowchart TD
A1[Acetylcholine] --> M3R
A2[Histamine] --> H2R
A3[Gastrin] --> CCK2R
M3R --> IP3Ca2_1[IP₃/Ca²⁺]
CCK2R --> IP3Ca2_2[IP₃/Ca²⁺]
H2R --> AC[Adelynate cyclase]
AC --> ATP
ATP --> cAMP
IP3Ca2_1 --> PK[Protein Kinase]
IP3Ca2_2 --> PK
cAMP --> PK
PK --> H_plus[H⁺]
PK --> HKATPase[H⁺/K⁺ ATPase]
PK --> K_plus[K⁺]
PK --> Cl_plus[Cl⁻]
subgraph Parietal Cell
M3R
H2R
CCK2R
IP3Ca2_1
IP3Ca2_2
AC
ATP
cAMP
PK
HKATPase
Cl_plus
end
H_plus --> Acid[Acid(HCl)]
Cl_plus --> Acid
K_plus --> HKATPase
HKATPase --> H_plus
HKATPase --> K_plus
PPI(PPI) --> HKATPase
HKATPase -.-|Inhibited| PPI
```
On the right:
* **Alginic acid forms a floating protectant vs GERD.**
* Bismuth subsalicylate coats and has an antimicrobial and antidiarrheal effect—used vs ulcers and traveler's diarrhea.
* **Antacids (magnesium, calcium, aluminum salts) raise pH.**
* Sucralfate binds to and protects the ulcer.
* Misoprostol (PGE2) protects vs ulcers from NSAIDs.
* **H₂ histamine receptor antagonists inhibit H$^+$ release by parietal cells.**
* **Proton pump inhibitors (e.g., esomeprazole, lansoprazole) reduce H$^+$ release from parietal cells.**
* Antibiotics (metronidazole, tetracycline, amoxicillin, clarithromycin) inhibit *H. pylori*, which can cause ulcers.
* "Stomach" label points to the stomach organ itself.
# **Cellular Mechanisms of Acid Secretion and Drug Action**
## **Parietal Cell Signaling Pathway**
```mermaid
flowchart TD
A1[Acetylcholine] --> M3R
A2[Histamine] --> H2R
A3[Gastrin] --> CCK2R
M3R --> IP3Ca2_1[IP₃/Ca²⁺]
CCK2R --> IP3Ca2_2[IP₃/Ca²⁺]
H2R --> AC[Adelynate cyclase]
AC --> ATP
ATP --> cAMP
IP3Ca2_1 --> PK[Protein Kinase]
IP3Ca2_2 --> PK
cAMP --> PK
PK --> H_plus[H⁺]
PK --> HKATPase[H⁺/K⁺ ATPase]
PK --> K_plus[K⁺]
PK --> Cl_plus[Cl⁻]
subgraph Parietal Cell
M3R
H2R
CCK2R
IP3Ca2_1
IP3Ca2_2
AC
ATP
cAMP
PK
HKATPase
Cl_plus
end
H_plus --> Acid[Acid(HCl)]
Cl_plus --> Acid
K_plus --> HKATPase
HKATPase --> H_plus
HKATPase --> K_plus
PPI(PPI) --> HKATPase
HKATPase -.-|Inhibited| PPI
```
## **Drug Mechanisms in the Stomach**
- **Alginic acid forms a floating protectant vs GERD.**
- Bismuth subsalicylate coats and has an antimicrobial and antidiarrheal effect—used vs ulcers and traveler's diarrhea.
- **Antacids (magnesium, calcium, aluminum salts) raise pH.**
- Sucralfate binds to and protects the ulcer.
- Misoprostol (PGE2) protects vs ulcers from NSAIDs.
- **H₂ histamine receptor antagonists inhibit H$^+$ release by parietal cells.**
- **Proton pump inhibitors (e.g., esomeprazole, lansoprazole) reduce H$^+$ release from parietal cells.**
- Antibiotics (metronidazole, tetracycline, amoxicillin, clarithromycin) inhibit *H. pylori*, which can cause ulcers.
- "Stomach" label points to the stomach organ itself.
# Laxatives
* **Stool softener**: docusate, liq paraffin, poloxamer
* **Stimulant laxative**: bisacodyl, senna, sodium picosulfate
* Act on nerve endings in colonic mucosa $\rightarrow$ increase intestinal motility
* **Osmotic laxative**: glycerol, lactulose, macrogol, saline laxatives, sorbitol
* Non-absorbable sugar $\rightarrow$ draw water into feces
* **Other**
* Bulk forming: absorb water in colon $\rightarrow$ increase fecal bulk
* Methylnaltrexone: Mu opioid receptor antagonist
* Prucalopride: 5HT4 receptor agonist $\rightarrow$ increase GI motility
| **Laxatives** | |
| :--- | :--- |
| **Stool softeners** | |
| | Docusate |
| | Liquid paraffin |
| | Poloxamer |
| **Stimulant laxatives** | |
| | Bisacodyl |
| | Senna |
| | Sodium picosulfate |
| **Osmotic laxatives** | |
| | Glycerol |
| | Lactulose |
| | Macrogol laxatives |
| | Saline laxatives |
| | Sorbitol |
| **Other laxatives** | |
| | Bulk-forming laxatives |
| | Methylnaltrexone |
| | Prucalopride |
# **Laxatives**
- **Stool softener**:
- Docusate, liq paraffin, poloxamer
- **Stimulant laxative**:
- Act on nerve endings in colonic mucosa → increase intestinal motility
- Bisacodyl, senna, sodium picosulfate
- **Osmotic laxative**:
- Non-absorbable sugar → draw water into feces
- Glycerol, lactulose, macrogol, saline laxatives, sorbitol
- **Other**:
- **Bulk forming:** absorb water in colon → increase fecal bulk
- **Methylnaltrexone:** Mu opioid receptor antagonist
- **Prucalopride:** 5HT4 receptor agonist → increase GI motility
| **Laxative Type** | **Generic Name** |
| :--- | :--- |
| **Stool softeners** | Docusate |
| | Liquid paraffin |
| | Poloxamer |
| **Stimulant laxatives** | Bisacodyl |
| | Senna |
| | Sodium picosulfate |
| **Osmotic laxatives** | Glycerol |
| | Lactulose |
| | Macrogol laxatives |
| | Saline laxatives |
| | Sorbitol |
| **Other laxatives** | Bulk-forming laxatives |
| | Methylnaltrexone |
| | Prucalopride |
Flowchart illustrating the mechanisms of action for different types of laxatives.
```mermaid
graph TD
subgraph Bulk-forming
direction LR
A[Examples:] --> B(psyllium)
B --> C(methylcellulose)
C --> D(polycarbophil)
D --> E[Increases stool mass]
end
subgraph Stimulant (irritant)
direction LR
F[Examples:] --> G(bisacodyl)
G --> H(senna)
H --> I(castor oil)
I --> J[Stimulates enteric nerves]
end
subgraph Osmotic
direction LR
K[Examples:] --> L(magnesium hydroxide)
L --> M(lactulose)
M --> N(polyethylene glycol (PEG))
N --> O[Increases fluid volume]
end
subgraph Wetting agents
direction LR
P[Examples:] --> Q(docusate)
Q --> R(mineral oil)
R --> S[Moistens to ease passage]
end
E --> T(Swelling & distending colon)
O --> T
T --> U[H₂O Uptake]
J --> V[Increased motility]
S --> W[Softer stool]
U --> X[Stool movement]
W --> X
V --> X
T --> Y(H₂O)
Z(H₂O) --> T
AA(H₂O) --> S
BB(H₂O) --> J
J --> CC(H₂O)
Y --> N
Z --> D
style T fill:#f9f,stroke:#333
style J fill:#f9f,stroke:#333
style Z fill:#f9f,stroke:#333
style Y fill:#f9f,stroke:#333
style AA fill:#f9f,stroke:#333
style CC fill:#f9f,stroke:#333
```
## **Mechanisms of Action for Laxatives**
```mermaid
graph TD
subgraph Bulk-forming
direction LR
A[Examples:] --> B(psyllium)
B --> C(methylcellulose)
C --> D(polycarbophil)
D --> E[Increases stool mass]
end
subgraph Stimulant (irritant)
direction LR
F[Examples:] --> G(bisacodyl)
G --> H(senna)
H --> I(castor oil)
I --> J[Stimulates enteric nerves]
end
subgraph Osmotic
direction LR
K[Examples:] --> L(magnesium hydroxide)
L --> M(lactulose)
M --> N(polyethylene glycol (PEG))
N --> O[Increases fluid volume]
end
subgraph Wetting agents
direction LR
P[Examples:] --> Q(docusate)
Q --> R(mineral oil)
R --> S[Moistens to ease passage]
end
E --> T(Swelling & distending colon)
O --> T
T --> U[H₂O Uptake]
J --> V[Increased motility]
S --> W[Softer stool]
U --> X[Stool movement]
W --> X
V --> X
T --> Y(H₂O)
Z(H₂O) --> T
AA(H₂O) --> S
BB(H₂O) --> J
J --> CC(H₂O)
Y --> N
Z --> D
style T fill:#f9f,stroke:#333
style J fill:#f9f,stroke:#333
style Z fill:#f9f,stroke:#333
style Y fill:#f9f,stroke:#333
style AA fill:#f9f,stroke:#333
style CC fill:#f9f,stroke:#333
```
# Anti-emetics
- **Nausea & vomiting**
- Rationale: prevent/ relieve sx
- Prevent complications (dehydration, electrolyte disturbance)
- **Dopamine antagonists**
- **Sedating antihistamines**
- Pheniramine & promethazine: px motion sickness
- **Anticholinergics**
- Hyoscine hydrobromide: px motion sickness
- **5HT3 antagonists, substance P antagonists, corticosteroids**
- Px nausea & vomiting assoc w/ chemotherapy
# **Anti-emetics**
- **Nausea & vomiting**
- Rationale: prevent/ relieve sx
- Prevent complications (dehydration, electrolyte disturbance)
- **Dopamine antagonists**
- **Sedating antihistamines**
- Pheniramine & promethazine: px motion sickness
- **Anticholinergics**
- Hyoscine hydrobromide: px motion sickness
- **5HT3 antagonists, substance P antagonists, corticosteroids**
- Px nausea & vomiting assoc w/ chemotherapy
**Dopamine antagonists**
* MOA: block dopamine receptor in **CTZ**
* **Dental implications**: dry mouth
* **Drug interaction**: prolongation of QT interval
* +Clarithromycin, erythromycin, fluconazole, moxifloxacin
| **Generic name** | **Brand Name** |
| :--- | :--- |
| Domperidone | Motilium |
| Droperidol | Droperidol inj |
| Haloperidol | Serenace |
| Metoclopramide | Maxolon |
| Prochlorperazine | Stemetil |
**5HT3 antagonists**
* MOA: block serotonin (5-HT3) receptors in the brain and gut
* [Granisetron] ADR: dry mouth, taste disturbance
* **Dental implications**
* Not directly but normally use adjunct in chemotherapy
| **Generic name** | **Brand Name** |
| :--- | :--- |
| Granisetron | Kytril |
| Ondansetron | Ondaz |
| Palonosetron | Aloxi inj |
| Tropisetron | Tropisetron inj |
## **Dopamine antagonists**
- **MOA:** block dopamine receptor in **CTZ**
- **Dental implications:** dry mouth
- **Drug interaction:** prolongation of QT interval
- +Clarithromycin, erythromycin, fluconazole, moxifloxacin
| **Generic name** | **Brand Name** |
| :--- | :--- |
| Domperidone | Motilium |
| Droperidol | Droperidol inj |
| Haloperidol | Serenace |
| Metoclopramide | Maxolon |
| Prochlorperazine | Stemetil |
## **5HT3 antagonists**
- **MOA:** block serotonin (5-HT3) receptors in the brain and gut
- **[Granisetron] ADR:** dry mouth, taste disturbance
- **Dental implications**
- Not directly but normally use adjunct in chemotherapy
| **Generic name** | **Brand Name** |
| :--- | :--- |
| Granisetron | Kytril |
| Ondansetron | Ondaz |
| Palonosetron | Aloxi inj |
| Tropisetron | Tropisetron inj |
**Sedating antihistamines**
* MOA: $\text{H}_1$ receptor and stabilising it in an inactive form
* Dental implications: sedation, dry mouth
* Drug interaction: nil in dental setting
| Generic name | Brand Name |
| :--- | :--- |
| Cyclizine | Nausicalm |
| Promethazine | Allersoothe, Phenergan |
**Anticholinergics**
* MOA: Block muscarinic actions of acetylcholine
* Dental implications: sedation, dry mouth
* Drug interaction: nil in dental setting
| Generic name | Brand Name |
| :--- | :--- |
| Hyoscine hydrobromide | Kwells, Travacalm |
## **Sedating antihistamines**
- **MOA:** $\text{H}_1$ receptor and stabilising it in an inactive form
- **Dental implications:** sedation, dry mouth
- **Drug interaction:** nil in dental setting
| Generic name | Brand Name |
| :--- | :--- |
| Cyclizine | Nausicalm |
| Promethazine | Allersoothe, Phenergan |
## **Anticholinergics**
- **MOA:** Block muscarinic actions of acetylcholine
- **Dental implications:** sedation, dry mouth
- **Drug interaction:** nil in dental setting
| Generic name | Brand Name |
| :--- | :--- |
| Hyoscine hydrobromide | Kwells, Travacalm |
# Substance P antagonists
* AKA: Also known as neurokinin-1 (NK1) receptor antagonists
* MOA: antagonize substance P/neurokinin-1 receptors.
* ADR: hiccups
* Drug interaction
* [CYP3A4 inH] azoles, clarithromycin, erythromycin: increase conc of substance P antagonist
| Generic name | Brand Name |
| :--- | :--- |
| Aprepitant | Aprepitant |
| Fosaprepitant | Emend inj |
| Fosnetupitant (+palonosetron) | Akynzeo inj |
# **Substance P antagonists**
- **AKA:** Also known as neurokinin-1 (NK1) receptor antagonists
- **MOA:** antagonize substance P/neurokinin-1 receptors.
- **ADR:** hiccups
- **Drug interaction**
- [CYP3A4 inH] azoles, clarithromycin, erythromycin: increase conc of substance P antagonist
| Generic name | Brand Name |
| :--- | :--- |
| Aprepitant | Aprepitant |
| Fosaprepitant | Emend inj |
| Fosnetupitant (+palonosetron) | Akynzeo inj |
# Anti-diarrheal
* **Rationale for drug therapy**
* Px dehydration & electrolyte disturbance
* Sx relief
* Tx of infection
* **Acute diarrhea: self limiting**
* **Chronic diarrhea: underlying disease req
investigations**
* **Drug therapy choice**
* ORS: $1^{\text{st}}$ line in children
* Opioid antidiarrheals: short term tx
| Generic name | Brand Name |
| :--- | :--- |
| **Codeine** | Codeine phosphate Actacode linctus |
| **Diphenoxylate + Atropine** | Lofenoxal Lomotil |
| **Loperamide** | Imodium |
# **Anti-diarrheal**
- **Rationale for drug therapy**
- Px dehydration & electrolyte disturbance
- Sx relief
- Tx of infection
- **Acute diarrhea:** self limiting
- **Chronic diarrhea:** underlying disease req investigations
- **Drug therapy choice**
- ORS: $1^{\text{st}}$ line in children
- Opioid antidiarrheals: short term tx
| Generic name | Brand Name |
| :--- | :--- |
| **Codeine** | Codeine phosphate Actacode linctus |
| **Diphenoxylate + Atropine** | Lofenoxal Lomotil |
| **Loperamide** | Imodium |
**Inflammatory bowel disease**
- **Crohn's disease & ulcerative colitis**
- Tx rationale: relieve sx & improve QOL, induce & maintain remission, px complications
- **Corticosteroids**
- Budesonide (oral), prednisolone (rectal)
- Adrenal suppression possible w/ budesonide
- Steroids ADRs
- **5-aminosalycilates**
- Mesalazine, Olsalazine, Sulfasalazine
| **Crohn's** | **Ulcerative colitis** |
| :--- | :--- |
| **5-aminosalicylates** | **5-aminosalicylates** |
| **Azathioprine & mercaptopurine** | **Azathioprine & mercaptopurine** |
| **Corticosteroids** | **Corticosteroids** |
| **TNFa antagonists** | **TNFa antagonists** |
| | **Cyclosporin** |
| **MTX** | |
| **Antibacterials for perianal fissures** | |
| - Metronidazole | |
| - Ciprofloxacin | |
# **Inflammatory bowel disease**
- **Crohn's disease & ulcerative colitis**
- **Tx rationale:** relieve sx & improve QOL, induce & maintain remission, px complications
- **Corticosteroids**
- Budesonide (oral), prednisolone (rectal)
- Adrenal suppression possible w/ budesonide
- Steroids ADRs
- **5-aminosalycilates**
- Mesalazine, Olsalazine, Sulfasalazine
## **Treatment Comparison**
| **Crohn's** | **Ulcerative colitis** |
| :--- | :--- |
| **5-aminosalicylates** | **5-aminosalicylates** |
| **Azathioprine & mercaptopurine** | **Azathioprine & mercaptopurine** |
| **Corticosteroids** | **Corticosteroids** |
| **TNFa antagonists** | **TNFa antagonists** |
| | **Cyclosporin** |
| **MTX** | |
| **Antibacterials for perianal fissures** | |
| - Metronidazole | |
| - Ciprofloxacin | |
**Corticosteroids**
**ADRs**
* Infection
* Delayed wound healing
* Steroid rosacea
* Perioral dermatitis
* Skin atrophy
* Bruising
* Acne
* Facial flushing
* Pupura
* Depigmentation
* Telangiectasia
* Steroid induced crushing's
![]()
Images showing different dermatological side effects of corticosteroids, including acne, rosacea, perioral dermatitis, and fat deposit buildup leading to a round face.
## **Corticosteroids ADRs**
- Infection
- Delayed wound healing
- Steroid rosacea
- Perioral dermatitis
- Skin atrophy
- Bruising
- Acne
- Facial flushing
- Pupura
- Depigmentation
- Telangiectasia
- Steroid induced crushing's
# 5-Aminosalicylates
* **MOA**
* Anti-inflammatory, immunosuppressant. Exact mechanism unknown
* Sulfasalazine: also indicated for RA (see RA lecture)
* **Indication**: UC, Crohn’s
* **ADR & drug interaction**: no dental implication
| Generic Name | Brand Name |
|---|---|
| Mesalazine | Mesasal |
| | Salofalk |
| Olsalazine | Dipentum |
| Sulfasalazine | Pyralin |
| | Salazopyrin |
# **5-Aminosalicylates**
- **MOA**
- Anti-inflammatory, immunosuppressant. Exact mechanism unknown
- Sulfasalazine: also indicated for RA (see RA lecture)
- **Indication:** UC, Crohn’s
- **ADR & drug interaction:** no dental implication
| Generic Name | Brand Name |
|---|---|
| Mesalazine | Mesasal |
| | Salofalk |
| Olsalazine | Dipentum |
| Sulfasalazine | Pyralin |
| | Salazopyrin |
**TNFa antagonists**
* MOA: binds & antagonize TNFa (cytokine involved in inflammatory & immune responses
* **Common adverse effect include infections**
* Persistent fever, other signs of infection, bruising, bleeding $\rightarrow$ Pt need to contact medical GP urgently
* Also indicated for RA (see RA lecture)
| Generic name | Brand Name |
| :--- | :--- |
| Adalimumab | Humira inj |
| Golimumab | Simponi inj |
| Infliximab | Remicade inj |
# **TNFa antagonists**
- **MOA:** binds & antagonize TNFa (cytokine involved in inflammatory & immune responses
- **Common adverse effect include infections**
- Persistent fever, other signs of infection, bruising, bleeding → Pt need to contact medical GP urgently
- Also indicated for RA (see RA lecture)
| Generic name | Brand Name |
| :--- | :--- |
| Adalimumab | Humira inj |
| Golimumab | Simponi inj |
| Infliximab | Remicade inj |
**Drugs for obesity**
* Orlistat
* **MOA**: inH GI lipases
* Fecal urgency/incontinence
* Phentermine
* **MOA**: sympathomimetic w/ CNS stimulatory effect
* CNS overstimulation
* Restlessness, nervousness, tachycardia, agitation, HTN, dry mouth!
* **Dietary and lifestyle factors**
| Generic name | Brand Name |
| :--- | :--- |
| Orlistat | Xenical |
| Phentermine | Duromine |
# **Drugs for obesity**
- **Orlistat**
- **MOA:** inH GI lipases
- Fecal urgency/incontinence
- **Phentermine**
- **MOA:** sympathomimetic w/ CNS stimulatory effect
- CNS overstimulation
- Restlessness, nervousness, tachycardia, agitation, HTN, dry mouth!
- **Dietary and lifestyle factors**
| Generic name | Brand Name |
| :--- | :--- |
| Orlistat | Xenical |
| Phentermine | Duromine |
# Total parenteral nutrition
* Total parenteral nutrition
* Method of feeding - Bypasses the gastrointestinal tract
* Nutrition is given into a vein
* Used when a person cannot or should not receive feedings or fluids by mouth
* **Pancreatic enzymes**
* Pancreatic enzyme insufficiency: cystic fibrosis
* Amylase, Lipase, Protease
* Irritation of skin around mouth & anus
| Generic name | Brand Name |
| :--- | :--- |
| Pancreatic enzymes | Creon |
| Ursodeoxycholic acid | Ursofalk |
# **Total parenteral nutrition**
- **Total parenteral nutrition**
- Method of feeding - Bypasses the gastrointestinal tract
- Nutrition is given into a vein
- Used when a person cannot or should not receive feedings or fluids by mouth
- **Pancreatic enzymes**
- Pancreatic enzyme insufficiency: cystic fibrosis
- Amylase, Lipase, Protease
- Irritation of skin around mouth & anus
| Generic name | Brand Name |
| :--- | :--- |
| Pancreatic enzymes | Creon |
| Ursodeoxycholic acid | Ursofalk |
**Gastrointestinal drugs**
**Dental implications**
* Drugs for gastric ulcer
* No real dental implications
* However, uncontrolled acid secretions $\rightarrow$ dental erosions
* Use of NSAIDs: close monitoring, risk Vs benefit
* **Drug interactions**
* Antacids: most interaction avoided by dosing interval of at least 2hrs
* Esomeprazole/omeprazole & diazepam
* H2 antagonists & PPIs: decrease absorption of itra- & ketoconazole $\rightarrow$ reduce antifungal effect
* Phentermine & tramadol: risks of seroT toxicity
# **Gastrointestinal drugs: Dental implications**
- **Drugs for gastric ulcer**
- No real dental implications
- However, uncontrolled acid secretions → dental erosions
- Use of NSAIDs: close monitoring, risk Vs benefit
- **Drug interactions**
- **Antacids:** most interaction avoided by dosing interval of at least 2hrs
- **Esomeprazole/omeprazole & diazepam**
- **H2 antagonists & PPIs:** decrease absorption of itra- & ketoconazole → reduce antifungal effect
- **Phentermine & tramadol:** risks of seroT toxicity
**IBD
Dental
implications**
* Oral manifestations of Crohn's disease & UC
* Pyostomatitis vegetans: rare, abscess & pustular lesions
* Recurrent aphthous ulcers: 1 or more
* Atrophic glossitis: red glossy tongue appearance
* Burning mouth syndrome
* Angular cheilitis: scaling & crusting corner of mouth
* Taste disturbance
* Dry mouth
* Halitosis
* Periodontitis
# **IBD: Dental implications**
- **Oral manifestations of Crohn's disease & UC**
- **Pyostomatitis vegetans:** rare, abscess & pustular lesions
- **Recurrent aphthous ulcers:** 1 or more
- **Atrophic glossitis:** red glossy tongue appearance
- **Burning mouth syndrome**
- **Angular cheilitis:** scaling & crusting corner of mouth
- **Taste disturbance**
- **Dry mouth**
- **Halitosis**
- **Periodontitis**
<div align="center">
<img src="crop1.jpg" alt="DermNet logo cropped">
</div>
| | | |
|---|---|---|
| **SORE TONGUE** | **IMPAIRED TASTE** | **DENTAL CARIES, PERIODONTAL DISEASES** |
| **EXTREME DRYNESS AND DISCOMFORT** | | **INFECTIOUS DISEASE** |
| **UPPER DIGESTIVE TRACT DISORDERS** | **DRY MOUTH** | |
| | | |
![]()
Images showing various oral health conditions and a diagram illustrating dry mouth symptoms.
<div align="center">
</div>
| | | |
|---|---|---|
| **SORE TONGUE** | **IMPAIRED TASTE** | **DENTAL CARIES, PERIODONTAL DISEASES** |
| **EXTREME DRYNESS AND DISCOMFORT** | | **INFECTIOUS DISEASE** |
| **UPPER DIGESTIVE TRACT DISORDERS** | **DRY MOUTH** | |
References
* Ritter JM, Flower RJ, Henderson G, Loke YK, MacEwan D, Robinson E, editors. *Rang & Dale’s pharmacology*. 10th ed. Edinburgh: Elsevier; 2023
* Australian Medicines Handbook Online [Internet]. Adelaide (AU): Australian Medicines Handbook Pty Ltd;2000. Gastrointestinal; [updated 2025; cited 2025]. Available from: UWA Onesearch
* Pharmaceutical Society of Australia. Australian Pharmaceutical Formulary and Handbook: A Guide to Best Practice. 25th ed. Canberra: Pharmaceutical Society of Australia; 2021
* Ali K. Clinical dental pharmacology. 1st ed. Oxford: Wiley-Blackwell; 2023
* Bullock S, Manias E. *Fundamentals of pharmacology*. 8th ed. Frenchs Forest, NSW: Pearson Australia; 2017
* MIMS Australia. *eMIMSelite: Consumer medicine information, specific clinical monograph* [Internet]. Sydney: MIMS Australia; [updated 2025; cited 2025 Apr 17]. Available from: UWA Onesearch
![]()
Three images related to medicine and illness, including a woman with cold symptoms and prescription bottles.
# **References**
- Ritter JM, Flower RJ, Henderson G, Loke YK, MacEwan D, Robinson E, editors. *Rang & Dale’s pharmacology*. 10th ed. Edinburgh: Elsevier; 2023
- Australian Medicines Handbook Online [Internet]. Adelaide (AU): Australian Medicines Handbook Pty Ltd;2000. Gastrointestinal; [updated 2025; cited 2025]. Available from: UWA Onesearch
- Pharmaceutical Society of Australia. Australian Pharmaceutical Formulary and Handbook: A Guide to Best Practice. 25th ed. Canberra: Pharmaceutical Society of Australia; 2021
- Ali K. Clinical dental pharmacology. 1st ed. Oxford: Wiley-Blackwell; 2023
- Bullock S, Manias E. *Fundamentals of pharmacology*. 8th ed. Frenchs Forest, NSW: Pearson Australia; 2017
- MIMS Australia. *eMIMSelite: Consumer medicine information, specific clinical monograph* [Internet]. Sydney: MIMS Australia; [updated 2025; cited 2025 Apr 17]. Available from: UWA Onesearch
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