Week 7: Anti-Infectives Flashcards
14 Prototype Anti Infective Drugs
- Penicillin
- Cephalosporins
- Aminoglycosides
- Tetracycline
- erythromycin
- ciprofloxacin (Cipro)
- metronidazole (Flagyl)
- Sulfa Drugs
- Isoniazid (INH)
- Rifampin (Rifadin)
- Amphotericin B (Fungizone)
- Acyclovir (Zovirax)
- zidovudine (Retrovir)
- saquinavir (Fortovase)
Selective Toxicity
a trait of a compound where it focuses on a specific organism or cell without injuring the host cells or body - does not cause unintended damage
Anti infectives interfere with what things?
Cell walls (bacteria have rigid cell walls, mammal cells dont)
Necessary Enzymes
Bacterial protein synthesis
Broad Spectrum v Narrow Spectrum
Broad agents kill off lots of organisms but narrow spectrums kill only one class or subclass of organism
We may end up treating with broad spectrum until we know exacts but broad spectrum opens up the possibility for microbial resistance
Bactericidal
Kills Bacteria
Bacteriostatic
Does not kill bacteria but prevents them from multiplying
Things will come to a halt and then the immune system finishes the job
What is important to do after C&S testing
match the bug to the drug!
Superinfection
“Secondary Infection”
A supra/secondary infection on top of a regular infection you already had
What are some common secondary infections
AAD Diarrhea
Urinary Pain, Infection
Vaginal Infections
Thrush
What is the most common secondary infection
AAD - Antibiotic Associated Diarrhea
How to avoid resistance in bacteria
avoid inappropriate use!!!
use narrow spectrum drugs when possible
send cultures and samples FIRST (before using anti infective agents)
do not discontinue ant infectives prematurely
anti infective use in animals, like livestock
Prophylaxis
Prevention through early drug use
not used as often as it once was
Prophylaxis with anti infectives is mainly for what situations
Surgery (but gets discontinued promptly)
Valvular Heart Disease (Endocarditis)
Immunosuppressed Patients
Penicillin
One of the first major classes of anti infective agents
A class of anti infectives with various preparations
Bacteriocidal
What is the action of penicillin
BACTERIOCIDAL - it interferes with bacterial cell wall synthesis and allows it to take up so much water -> increase osmotic pressure -> bursts
Penicillin is bacteriostatic of bactericidal
Bactericidal
Penicillin mostly affects what type of bacteria
gram positive bacteria
What sort of bacterial cells does penicillin influence
new and newly forming ones not already mature cells
Penicillin drugs usually end in what suffix
-cillin
What is the most common ADR of penicillin
GI Symptoms
What is the major ADR of concern with Penicillin
ANAPHYLACTIC REACTIONS
Includes: Vascular Collapse, Cardiac Arrest, Laryngeal Edema, Bronchospasm
A fairly high incidence of allergic rxns exist
What is penicillin densitization
a treatment designed to help the body overcome penicillin allergies
What is a mechanism bacteria have developed to stop the effect of penicillin
some bacteria produce penicillinase (usually Beta lactamase) which will block the action of penicillin
How have we overcome the defense of penicillinase in resistant bacteria
We mix penicillin with a beta lactamase inhibitor like K Clavulanate (together makes Augmentin) to inhibit that effect and allow penicillin to work
What is the important Beta Lactamase Inhibitor often mixed with penicillin
Potassium (K) Clavulanate
Cephalosporins
A type of antimicrobial that is the most extensively used type of antimicrobial used worldwide
Has 5 generations of types with each successive one getting more improvements
What is often seen in the name of a cephalosporin drug
“Cef” or “Ceph” in the generic name
What is often used as an alternative to penicillin
Cephalosporins (To prevent allergic reactions)
What is the most extensively used antimicrobial worldwide
cephalosporins
Are cephalosporins bactericidal or bacteriostatic
Bactericidal
Action of Cephalosporins
Bactericidal - related to penicillin structurally and pharmacologically so it inhibits mucopeptide synthesis of the bacteria cell wall
New cell walls cannot form
What is interesting about the absorption of cephalosporins
Can be given oral or IV but it is better absorbed on an empty stomach
ADRs of Cephalosporins
Allergic Rxn, Rash
N/V/D
Phlebitis
Superinfection
Sometimes: Kidney Damage, Bone Marrow Depression, Mild Hepatotoxicity, Acute Colitis
Some cause bleeding tendencies by decreasing prothrombin levels or interfering with platelet aggregation
What is the unique ADR of cephalosporins
Phlebitis - inflammation of veins; may be at the IV site - more common with cephalosporins
What is important to keep in mind even if you are using cephalosporins instead of penicillin
There is a partial cross allergy that exists for those hypersensitive to penicillin, 1% of the population, that are also allergic to cephalosporins if they are allergic to penicillin
Cephalosporins are commonly used as…
an alternative to penicillin
Vancomycin
Only drug in its own class that also impacts the cell wall, but also inhibits RNA synthesis
used for serious and resistant infections like MRSA and VRE
It impacts gram positive organisms but is highly regulated because of resistance
ADRs: Hearing and Kidney Damage, Histamine Release leading to Red Man Syndrome, Anaphylaxis, Ototoxicity
Aminoglycosides
Class of antimicrobials that are not seen as often as penicillin or cephalosporins but are used for serious infections
ex: Gentamicin, Streptomicin, Neomycin, Amikacin, Tobramycin
Is there a suffix or prefix specific to aminoglycosides
no, mycin is commonly seen but it is not specific to this class alone
Action of Aminoglycosides
Bactericidal or Bacteriostatic!
Instead of working on cell walls, it directly impacts protein synthesis instead - it impacts 30S Subunits of the ribosomes
Are aminoglycosides narrow or broad spectrum
narrow they are used for serious infections of gram negative bacteria to impact their protein synthesis
What is the therapeutic level of gentamycin (a type of aminoglycoside)
4-8 mg/L
This is just for gentamycin, all aminoglycosides have different levels
Why do we monitor peaks and trough levels very carefully for aminoglycosides
Potential Kidney Damage - we want above MEC but below maximum
Other ADRs as well
What anti microbial is very important to have drug levels drawn and administration timing exact because of potential impacts
Aminoglycosides
Aminoglycosides effect what type of organism
serious aerobic gram negative ones - that could cause sepsis
ADRs of Aminoglycosides
- Potential Kidney Damage (Proteinuria)
- Vestibular Issues (vertigo and loss of balance)
- Auditory issues (deafness)
Other: high doses cause neuromuscular issues causing resp. paralysis ; Enhance blockade of skeletal muscle relaxants
It may not be a good idea to give aminoglycosides with what
skeletal muscle relaxants
Why are aminoglycosides used less nowadays
because they have serious side effects and there are newer drugs that can be used without these side effects
What is important to know about giving an aminoglycoside to a geriatric patient, premature patient, or renal failure patient
These factors increase the incidence of ototoxicity
Why may we not give aminoglycosides to someone with renal insufficiency
it can cause further kidney damage!
What is the problem with IV form aminoglycosides
there are many incompatibilities with other drugs in this form
Neomycin
a type of aminoglycoside
it is a topical one that works locally at area of instillation
it may be used to sterilize the GI tract to prevent gram negative sepsis within a surgery
When thinking of aminoglycoside ADRs, think ___, ___, and ____
Kidneys (Nephrotoxicity), Ears (Ototoxicity), Neurons (Neurotoxicity)
Why is the neurotoxicity of aminoglycosides less of an immediate concern as compared to the nephrotoxicity or ototoxicity
Because while there is high potential, it only occurs in higher doses which are rarely if ever given
Tetracyclines
class of antimicrobial drugs
used for a variety of infections when penicillin cannot be used, but is more pleasant in use than aminoglycosides
ex: Doxycycline, Achromycin, Terramycin
When might a tetracycline be given
if someone is allergic to penicillin/cephalosporin, and in substitute to a more serious aminoglycoside (more pleasant ADR wise)
Tetracyclines are ___ use, why?
broad; they are used for many conditions including:
Acne Chlamydia Rocky Mtn Spotted Fever Rickettsial Disease Psittacosis Cholera Lyme Disease !!!! H Pylori !!! Mycoplasma Pneumonia
What is the problem with use of tetracyclines
if they are used to much it leads to resistance
Action of Tetracycline
Inhibits protein synthesis by binding to the ribosomal sub unit - so it only affects rapidly multiplying organisms
Is tetracyclines bactericidal or bacteriostatic
Bacteriostatic normally, but it is bactericidal at higher doses
Tetracyclines are relatively _______
non-toxic
ADRs of Tetracyclines
- Photosensitivity
- Child Tooth Mottling
Other: Sensitization, Anaphylaxis, GI discomfort, Dizziness, Ataxia, Nephropathy
Why does tetracyclines cause child tooth mottling
because if the child’s permanent teeth are still developing, tetracyclines will bind to calcium and leave permanent staining in the teeth
What is important to know about when absorption interference and tetracyclines
do NOT take with food - especially dairy products or antacids because they will chelate the drug and decrease absorption
however, they will readily bind with calcium, Mg, Aluminum, zinc and iron
How does Doxycycline differ from other tetracyclines
dairy products and antacids will not decrease its absorption - non affected
What patients have tetracycline contraindicated
those with renal dysfunction
it does not cause it but it does linger
_____ are a type of anti microbial used for so many conditions
Tetracyclines
Macrolide Antimicrobial
Macrolides are a family of drugs
they inhibit bacterial protein synthesis like aminoglycosides and tetracycline
What is the prototype drug for macrolides
erythromycin (E-Mycin, Ery-Tab)
Erythromycin
macrolide antimicrobial prototype
What is the action of erythromycin
blocks ribosomal sub unit to prevent new AA to chain –> Inhibits protein synthesis
erythromycin is similar to what drugs and is often used as the preferred substitute
penicillin
Is erythromycin bactericidal or static
Bacteriostatic normally, but can be bactericidal against certain organisms or at high doses