Antibiotics

Question 1

Antibiotics classification

Answer 1

Based on:

1. Mechanism of action
2. Gram-positive gram-negative
3. Anaerobic, aerobic, and facultative organisms

Question 2

Antibiotic classification based on their actions

Answer 2

BacteriCIDAL kill bacteria—-example, penicillin, and cephalosporins (pc)

BacterioSTATIC—-stop bacteria from reproducing, but not harming them

Example, tetracycline and clindamycin (tc)

Question 3

Drugs which are static in lower doses, and cidal in higher doses

Answer 3

ClINDAMYCIN and
MACROLIDES
(CM)

Important : when giving an antibiotic do not mix static and cidal

Question 4

Antibiotics, classification based on mechanism of action

Answer 4

1. Affecting cell wall.
2. Interfering with protein synthesis.
3. Interfering with normal biosynthetic pathways.
4. Affecting bacterial DNA.

Question 5

Affecting cell wall

Answer 5

Usually affect the synthesis of PEPTIDOGLYCAN which is the main component of cell wall

Example :
Beta lactams like
penicillins
cephalosporins
Mono bactams
Carbepenems
Bacitracin
Aztreonam

Question 6

Affecting protein synthesis

Answer 6

30 S ribosome units
Aminoglycosides
Tetracyclines

50th ribosome units
Macrolides
Chloraphenicol

Question 7

Affecting the normal biosynthetic pathway or the metabolic pathway

Answer 7

Folic acid synthesis
Sulfonamides
Trimethoprim

Mycolic acid synthesis
Isoniazide

Question 8

Affecting bacterial, DNA

Answer 8

Flora quinolones-used in periodontal infections
example ciprofloxacin
Levofloxacin
Moxifloxacin

Metronidazole — antiprotozoal agent, but has antibacterial properties as well. It is used in periodontal infection.

RNA synthesis
Rifampin

Question 9

Common side effects of antibiotics in Dentistry

Answer 9

1. Development of bacterial resistance.
2. Allergic reaction.
3. G.I. problems.-mainly by clindamycin.
4. Super infection.-example candidal infection.

Question 10

interaction between Antibiotics, example, tetracycline, and oral anticoagulants

Answer 10

Oral anticoagulants are vitamin K inhibitors, so they increase the anticoagulant effect

Antibiotics and oral anticoagulants ——-POTENTIATE the anticoagulant effect——— monitor INR

Question 11

Beta-lactam antibiotics

Answer 11

Penicillin
Cephalosporin
Carbepenems
Monobactams

Question 12

Beta lactam Antibiotics are.

Answer 12

Bactericidal
Narrow spectrum
Drug of choice in dental infection

Question 13

Majority of the dental infections are caused by

Answer 13

Gram-positive, facultative, anaerobic, bacteria, example, beta haemolytic streptococcus

Question 14

Penicillin G, (Benzyl penicillin)

Answer 14

It’s the prototype penicillin
Very low resistant to stomach acid
Usually injected

Question 15

Penicillin, VK (phenoxy methyl penicillin)

Answer 15

More acid stable given orally
Used to treat oral infections

Question 16

Penicillin G benzathine IM)

Answer 16

Not commonly used in dentistry
Used to treat syphilis

Question 17

Principal difference between the potassium procaine and benzathine salts of penicillin G

Answer 17

Duration of action

Question 18

Drug of choice in management of dental infections like a cute dental abscess

Answer 18

Penicillin

Because it has narrow spectrum, Bactericidal action against beta haemolytic streptococcus

Question 19

Mechanism of action of penicillin

Answer 19

Inhibits bacterial cell wall synthesis by blocking transpeptidase enzyme-Bactericidal

Question 20

Spectrum of action

Answer 20

Gram-positive, organism, cocci and rods
Graham negative cocci
Spirochaetes

Narrow spectrum

Question 21

Most common bacteria to develop antibiotic resistance

Answer 21

Staphylococci

Question 22

Why is treating staphylococcus aureus infection? Difficult with penicillin

Answer 22

Due to the production of penicillinase by microorganisms

Question 23

Antibiotic of choice for this exam

Answer 23

Penicillin, VK

Second is amoxycillin

Question 24

Diarrhoea

Answer 24

Most common with clindamycin

Penicillin is also likely to cause diarrhoea

Question 25

PDF for choosing an antibiotic

Answer 25

It should be cheap Should have a narrow spectrum

Question 26

Affects of penicillin

Answer 26

Allergenicity is a major technical problem(10%) Most common allergic manifestation is skin rash (a delayed reaction ) Other signs include Dermatitis Stomatitis Bronchoconstriction Cardiovascular collapse The risk of anaphylaxis (immediate reaction) is rare

Question 27

In odontogenic infections, the first choice is

Answer 27

Penicillin V

Question 28

Penicillinase resistant

Answer 28

Methicillin Nafcillin Oxacillin

Question 29

Anaphylactic reaction

Answer 29

Occurs when drug is given parenterally Impatience have already experienced an allergic reaction Bacon having a positive skin test to penicillin allergy

Question 30

Acid stable penicillins

Answer 30

Can be used orally Penicillin V Amoxycillin Ampicillin Nafcillin Oxacillin Cloxacillin Dicloxacillin

Question 31

Therapeutic advantage of penicillin V over penicillin G

Answer 31

Greater absorption, when given orally

Question 32

Broad-spectrum penicillins

Answer 32

Used for urinary tract infection Piperacillin Ticarcillin

Question 33

Sinusitis

Answer 33

Odontogenic First choice is: Penicillin VK Amoxycillin Non-odontogenic infections Augmentin Amoxycillin Cephalexin