Antibiotics Flashcards
Antibiotics classification
Based on:
- Mechanism of action
- Gram-positive gram-negative
- Anaerobic, aerobic, and facultative organisms
Antibiotic classification based on their actions
BacteriCIDAL kill bacteria—-example, penicillin, and cephalosporins (pc)
BacterioSTATIC—-stop bacteria from reproducing, but not harming them
Example, tetracycline and clindamycin (tc)
Drugs which are static in lower doses, and cidal in higher doses
ClINDAMYCIN and
MACROLIDES
(CM)
Important : when giving an antibiotic do not mix static and cidal
Antibiotics, classification based on mechanism of action
- Affecting cell wall.
- Interfering with protein synthesis.
- Interfering with normal biosynthetic pathways.
- Affecting bacterial DNA.
Affecting cell wall
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
Affecting protein synthesis
30 S ribosome units
Aminoglycosides
Tetracyclines
50th ribosome units
Macrolides
Chloraphenicol
Affecting the normal biosynthetic pathway or the metabolic pathway
Folic acid synthesis
Sulfonamides
Trimethoprim
Mycolic acid synthesis
Isoniazide
Affecting bacterial, DNA
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
Common side effects of antibiotics in Dentistry
- Development of bacterial resistance.
- Allergic reaction.
- G.I. problems.-mainly by clindamycin.
- Super infection.-example candidal infection.
interaction between Antibiotics, example, tetracycline, and oral anticoagulants
Oral anticoagulants are vitamin K inhibitors, so they increase the anticoagulant effect
Antibiotics and oral anticoagulants ——-POTENTIATE the anticoagulant effect——— monitor INR
Beta-lactam antibiotics
Penicillin
Cephalosporin
Carbepenems
Monobactams
Beta lactam Antibiotics are.
Bactericidal
Narrow spectrum
Drug of choice in dental infection
Majority of the dental infections are caused by
Gram-positive, facultative, anaerobic, bacteria, example, beta haemolytic streptococcus
Penicillin G, (Benzyl penicillin)
It’s the prototype penicillin
Very low resistant to stomach acid
Usually injected
Penicillin, VK (phenoxy methyl penicillin)
More acid stable given orally
Used to treat oral infections
Penicillin G benzathine IM)
Not commonly used in dentistry
Used to treat syphilis
Principal difference between the potassium procaine and benzathine salts of penicillin G
Duration of action
Drug of choice in management of dental infections like a cute dental abscess
Penicillin
Because it has narrow spectrum, Bactericidal action against beta haemolytic streptococcus
Mechanism of action of penicillin
Inhibits bacterial cell wall synthesis by blocking transpeptidase enzyme-Bactericidal
Spectrum of action
Gram-positive, organism, cocci and rods
Graham negative cocci
Spirochaetes
Narrow spectrum
Most common bacteria to develop antibiotic resistance
Staphylococci
Why is treating staphylococcus aureus infection? Difficult with penicillin
Due to the production of penicillinase by microorganisms
Antibiotic of choice for this exam
Penicillin, VK
Second is amoxycillin
Diarrhoea
Most common with clindamycin
Penicillin is also likely to cause diarrhoea
PDF for choosing an antibiotic
It should be cheap
Should have a narrow spectrum
Affects of penicillin
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
In odontogenic infections, the first choice is
Penicillin V
Penicillinase resistant
Methicillin
Nafcillin
Oxacillin
Anaphylactic reaction
Occurs when drug is given parenterally
Impatience have already experienced an allergic reaction
Bacon having a positive skin test to penicillin allergy
Acid stable penicillins
Can be used orally
Penicillin V
Amoxycillin
Ampicillin
Nafcillin
Oxacillin
Cloxacillin
Dicloxacillin
Therapeutic advantage of penicillin V over penicillin G
Greater absorption, when given orally
Broad-spectrum penicillins
Used for urinary tract infection
Piperacillin
Ticarcillin
Sinusitis
Odontogenic
First choice is:
Penicillin VK
Amoxycillin
Non-odontogenic infections
Augmentin
Amoxycillin
Cephalexin
