Oral Medicine - Pharmacology

Question 1

What are the 5 classes of antibiotics?

Answer 1

Beta-lactams
Macrolides
Lincosamides
tetracycline
nitroimidazole

Question 2

Mechanism of action of beta lactams

Answer 2

Inhibit cell wall synthesis

Question 3

Which bacterial enzyme facilitates antibiotic resistance to beta-lactams?

Answer 3

Beta lactamase

Question 4

What is the name of a beta lactamase inhibitor?

Answer 4

Clavulanic Acid

Question 5

What is the dosage for amoxycillin + clavulanic acid?

Answer 5

500mg +250mg 8 hourly for 5 days

Question 6

What type of bacteria are beta lactams active against?

Answer 6

Broad spectrum gram positive and negative bacteria

Question 7

What is the mechanism of action of macrolide antibiotics?

Answer 7

inhibits protein synthesis

Question 8

List 3 macrolide antibiotics

Answer 8

erythromyxin, roxithromyxin, clarithromycin

Question 9

What is a possible side effect of macrolide antibiotics?

Answer 9

Increase risk of cardiac arrhythmias due to QT prolongation
QT is the time for ventricular repolarisation. Elongation = tachycardia

Question 10

What is a problem with the use of macrolide antibiotics in the dental setting?

Answer 10

There is little activity against periodontal pathogens and declining activity against strep sp.

Question 11

What is an example of a lincosamide antibiotic?

Answer 11

Clindamycin

Question 12

When are lincosamides used?

Answer 12

If ptn is non-responsive to amoxycillin + clavulanic acid

Question 13

What is the dosage for clindamycin?

Answer 13

150mg 4/day

Question 14

Why are tetracyclines the first line of treatment for periodontal infections?

Answer 14

Active against periodontal pathogens
increased bioavailability in the gingival sulcus

Question 15

2

What are the side effects of tetracycline?

Answer 15

Staining - dental, oral , skin
hypersensitivity to sun

Question 16

What is an example of a nitroimidazole antibiotic?

Answer 16

Metronidazole

Question 17

What is a common dental use for metronidazole?

Answer 17

ANUG
Pericorinitis
adjunct to amoxycillin for spreading infection

Question 18

What is the dosage for metronidazole?

Answer 18

200mg 3/day for 3 days
severe: 400mg 2/day for 5 days

Question 19

What is the mechanism of action of metronidazole?

Answer 19

Pro-drug - when metabolised by anaerobic bacteria it becomes bacterocidal

Question 20

What is the interaction between metronidazole and warfarin?

Answer 20

Metronidazole delays the metabolism of warfarin and therefore should be avoided in ptn on warfarin

Question 21

What is the mechanism of action of chlorhexidine?

Answer 21

Bacterostatic (0.02%-0.06%)
Bacterocidal (>0.12%)

Question 22

What is chlorhexidine active against?

Answer 22

gram positive bacteria, fungi, some viruses (HIV, HSV, CMV, Influeza)

Question 23

What are the risks of chlorhexidine?

Answer 23

Brown discolouration of teeth and tongue
temporary taste alteration
mucosal burn in high concentration
allergic reraction

Question 24

What is the protocol for chlorhexidine mouthwash?

Answer 24

0.12-0.2% 15ml for 30 sec 2/day

Question 25

What does the addition of povidone to iodine achieve?

Answer 25

Organic carrier that controls the release of iodine

Question 26

What is povidone iodine active against?

Answer 26

Perio pathogens, mycobacteria, virus, protozoa | i.e bacteria, fungus, virus

Question 27

Which antiseptic agent shouldn't be used if ptn has a history of thyroid dysfunction?

Answer 27

Povidone Iodine

Question 28

What is the difference between hyposalivation and xerostomia?

Answer 28

Hyposalivation = objective measurement Xerostomia = subjective feeling

Question 29

What conditions can contribute to xerostomia? (5)

Answer 29

Sjogrens Head and neck radiation Type II diabetes mental health and stress medications

Question 30

What are non-pharmacological options for treatment of xerostomia?

Answer 30

increased water intake xylitol gum decreased caffeine decreased alcohol natural lubricants e.g olive oil

Question 31

What is a commercial oral lubricant?

Answer 31

carboxymethylcellulose

Question 32

what is added to commercial lubricants to increase effectiveness?

Answer 32

Antimicrobials: lactoferin lysozyme (in natural saliva) lactoperoxidase (biotene)

Question 33

What is a sialogogue?

Answer 33

an agent promoting secretion of saliva

Question 34

What is a non-pharmocological sialogogue?

Answer 34

Chewing gum

Question 35

What is a topical pharmacological sialogogue?

Answer 35

1% Malic acid

Question 36

What is an example of a systemic sialogogue?

Answer 36

Pilocarpine

Question 37

What is the dosage of pilocarpine?

Answer 37

5mg 3/day for atleast 3 months

Question 38

What are the risks of pilocarpine?

Answer 38

GI upset blurred vision stimulation of other exocrine glands e.g lacrimal

Question 39

What are underlying risk factors for oral candidiasis?

Answer 39

Diabetes Anaemia HIV Immunosuppression or deficiency cancer Denture wearers (poor hygiene)

Question 40

What is the most important factor in managing oral candidosis?

Answer 40

manage underlying risk factor

Question 41

What are the 3 groups of antifungals?

Answer 41

Polyenes Ergosterol Biosynthesis inhibitors Newer agents

Question 42

# 2 Example of polyene antifungals?

Answer 42

Nystatin Amphotericin B

Question 43

Example of ergosterol biosynthesis inhibitors

Answer 43

"azole" miconazole clotrimazole itraconazole fluconazole

Question 44

Which antifungal should be avoided in diabetes and why?

Answer 44

Nystatin contains sucrose

Question 45

Why shouldn't clotrimazole be taken systemically?

Answer 45

GI and neurolgical side effects

Question 46

A ptn on warfarin shouldn't take this class of antifungal. Why?

Answer 46

Ergosterol Biosynthesis inhibitors "azole" decreases metabolism of warfarin = increased effect of warfarin = risk of bleeding

Question 47

What is the protocol for miconazole in the treatment of oral candidiasis?

Answer 47

Gel 2% 2.5ml 3/day for 7-14 days and 7 days after symptoms resolve

Question 48

What is the protocol for nystatin in the treatment of oral candidiasis?

Answer 48

100,000units/ml 1ml 4/day for 7-14 days, 2-3 days after symptoms resolve

Question 49

What are the 3 aims of antiviral medications?

Answer 49

1. block viral replication 2. shorten duration of symptoms 3. accelerate healing of lesions

Question 50

Which HSV virus type is herpes labialis associated with?

Answer 50

HSV1

Question 51

What are the 3 drug classes of antivirals?

Answer 51

1. Acyclic Guanosine Anologues "clovir" 2. Acyclic Neucleotide Analogues "fovir" 3. pyrophosphate anologue "forscanet"

Question 52

Which virus type is acyclovir active against?

Answer 52

Herpes virus

Question 53

Why does acyclovir required early administration to be effective?

Answer 53

Targets viral replication which occurs in the first 48hours of infection. After this viral replication decreases so medication is less effective.

Question 54

What is the use of forscarnet?

Answer 54

CMV or acyclovir resistance HSV in immunocompromised patients

Question 55

What are glucocorticoids?

Answer 55

Synthetic anologue of cortisol hormone produced by adrenal glands.

Question 56

When is the peak production of natural cortisol? How does this affect dosage/prescription?

Answer 56

Morning Ptn should take corticoids in morning for maximal effect

Question 57

How much cortisol does the body naturally produce?

Answer 57

20-30mg

Question 58

What are the side effects of glucocorticoids?

Answer 58

Weight gain osteoporosis increased blood glucose

Question 59

List 5 common glucocorticoids?

Answer 59

Betamethasone Dexamethasone Methylprednisolone Prednisolone Deflazacort

Question 60

What are the symptoms of corticosteroid withdrawl syndrome?

Answer 60

Arthralgia myalgia mood changes and fatigue headache GI problems

Question 61

What is a method for increasing the contact time of topical corticosteroids with the oral mucosa?

Answer 61

Use in conjunction with an adhesive gel e.g orabase

Question 62

what are the instructions given to patients for topical corticosteroids?

Answer 62

contact time = 4-30 min 2-3/day (depends on type) avoid talking, eating, drinking rinsing during this time

Question 63

What are 3 types of corticosteroid based mouthwashes?

Answer 63

Klobetasol proprionate dexamethasone proprionate betamethason proprionate

Question 64

What is the benefit of intralesion corticosteroid injections?

Answer 64

decreased side effect increased concentration of corticosteroid at injection site

Question 65

Describe what corticosteroid sparing is

Answer 65

prescription of immunosuppresive or anti-inflammatory agnets to decrease the ptn's cumulative exposure to systemic corticosteroids