Antibiotics & Antifungals p2 Flashcards
Antimicrobials Mechanism of Action
Cell wall agents (2)
- Penicillin
- Cephalosporins
Antimicrobials Mechanism of Action
Protein synthesis agents (3)
- Macrolides
- Aminoglycosides
- Tetracyclines
Antimicrobials Mechanism of Action
Antimetabolites (1)
Sulfonamides
Antimicrobials Mechanism of Action
Nucleic acid agents (1)
Quinolones
Antimicrobials Mechanism of Action
Antifungal agents (2)
- Azoles
- Polyenes
Penicillin’s (cell wall agent)
1. Structure
2. Identified by
3. Spectrum of activity
- Beta-lactam that interferes with bacterial cell wall synthesis
- By the “-cillin” ending in name
- Depends on the type of penicillin
Beta-lactamase resistant penicillins, or potentiated penicillins, are more ___ to beta-lactamase.
Examples of this are (6)
Resistant
Examples:
1. Methicillin
2. Oxacillin
3. Dicloxacillin
4. Cloxacillin
5. Floxacillin
6. Amoxicillin & Clavulanic acid
- Which binds to beta-lactamase to prevent the beta-lactam ring from being destroyed.
Cephalosporins (cell wall agents)
1. What are they
2. How are they identified?
3. How many classifications are they divided into?
- Are semi-synthetic, broad spectrum antiB that are structurally related to the penicillins.
- Have beta-lactam ring - Identified by “ceph-“ or “cef-“ in drug name.
- Four
- As the number of generations increases, the spectrum of activity broadens (becomes less effective against g- bacteria tho)
Cephalosporins precautions (2)
- Allergic reactions & triggers to immune-mediated reactions are biggest concerns
- If occurs, avoid all drugs in this class! - NEVER used in hind-gut fermenters due to destruction of normal bacterial flora
- Rabbits, guinea pigs
T/F: Cephalosporins are generally safe group of drugs because they work against cell walls and animal cells do not have walls
True! They only have membranes
Aminoglycosides (protein synthesis agents)
1. Interfere with what?
2. Side effects (2)
3. Examples (3)
- The production of protein in bacterial cells
- Nephrotoxicity & Ototoxicity
- Examples
- Gentamicin
- Neomycin
- Amikacin
Aminoglycosides (protein synthesis agents)
1. Spectrum of activity:
2. Used for G- or G+?
- Broad spectrum activity
- G- bacteria
T/F: Aminoglycosides are not absorbed well from the GI tract, so they are given parentally
True
- What should be monitored for nephrotoxicosis when giving aminoglycosides? (3)
- When should it begin? How frequently should it be?
- If renal damage is present prior to therapy, what should happen?
- BUN, Sp. Gr., urine sediment for cellular casts.
- Begin day 3 of therapy and repeated daily while on this class of drugs.
- Avoid this drug class! Stop meds if renal damage becomes present after meds begin!
Tetracyclines (protein synthesis agents)
1. Interfere with what?
2. What are they?
3. Examples (4)
- Production of protein in bacterial cells
- Group of antiB with a broad-spectrum activity
- Including rickettsial agents - Examples
- Tetracycline
- Oxytetracycline
- Doxycycline
- Minocycline
How do tetracyclines work?
They can bind to calcium and be deposited in growing bones and teeth or bind components of antiacids and other mineral-containing compounds.
Precautions of protein synthesis agents (4)
- Do not give to neonates before permanent teeth have erupted.
- Doxycycline can cause esophageal damage in cats. Water by syringe or feeding should occur IMMEDIATELY after pilling!
- No dairy. Will ruin med effects - Can cause sudden death if given IV in horses
- Avoided in pregnant animals!
Chloramphenicol (protein synthesis agents)
1. Interferes with what?
2. What is it?
3. Effective against what?
- Production of protein in bacterial cells
- A broad spectrum antiB that penetrates tissues & fluids well (including eyes & CNS)
- Toxoplasmosis
T/F: Chloraphenicol has toxic side effects that can cause bone marrow depression in people so you must wear gloves when administering
True!
Macrolides (protein synthesis agents)
1. Interfere with what?
2. What are they?
3. Examples (3)
- Production of protein in bacterial cells
- Broad spectrum antiB that have a large molecular structure
- Examples
- Erythomycin
- Tylosin
- Tilmicosin
What are microslides used to treat? (2)
- Penicillin-resistant infections
- Animals that have allergic reactions to penicillin’s
Sulfonamides (antimetabolites)
1. Inhibits what?
2. What are they
3. Side effects (4)
4. Examples (3)
- Inhibit the synthesis of folic acid (needed for growth in bacteria)
- Broad spectrum antiB
- Crystalluria, KCS (dry eye), Platelet disorders, Skin rashes (esp in cocker spaniels).
- Examples
- Sulfadiazine / Trimethoprim
- Sulfadimethoxine
- Sulfadimethoxine / Ormetoprim
Fluoroquinolones (nucleic acid agents)
1. What is it?
2. Side effects (2)
3. Examples (5)
4. How is the drug name recognized?
- Broad spectrum antiB
- Development of bubble-like cartilage lesions in growing dogs
AND crystalluria. - Examples
- Enrofloxacin
- Ciprofloxacin
- Orbifloxacin
- Difloxacin
- Marbofloxacin - “-floxacin” ending in name
T/F: Vision damage can occur in cats when using fluoroquinolones in low doses
False! This can occur when using HIGH doses
Metronidazole
1. Mechanism of action
2. Effective against what? (2)
3. Effect in intestines?
- Unknown
- Protozoa (giardia) & anaerobic bacteria
- Anti-inflammatory effects in intestines
Metronidazole precaution (1)
Can cause neurologic signs (nystagmus) if used at high doses or for long periods of time
