Week 3- Antibiotics Flashcards
What are narrow spectrum antibiotics?
antibiotics effective against only a few microorganism with a very specific metabolic pathway or enzyme
tetracycline is contraindicated for which types of pts and has an adverse effect on which population?
contraindicated for children under 8 bc TCN binds to calcium causing discoloration and hypoplasia of teeth and has an adverse effect on pregnant women bc TCN may retard fetal skeletal development
MOA of aminoglycosides
Bacteriocidal
most effective for aerobic gram (-) bacteria
for serious to life-threatening infections with serious toxicities (ototoxicity and nephrotoxicity most prevelant)
rearely used in PO form except for bowel pre-op bowel cleanse
Adverse effects of macrolides?
Jaundice
Hepatotoxicity
Superinfection
Macrolides are highly protein bound and can have serious interaction with other protein-bound drugs
what is the MOA of Sulfonamides?
bacteriostatic by preventing Bacteria (not human) synthesis of Folic Acid
Is pyridium an antibiotic? If not, what is it?
no, its an analgesic
Amoxicillin (PO) and Ampicillin (PO/IM/IV) fall under which type of Penicillan? Which bacteria are they good for?
Aminopenicillins. Good for gram (-) and gram (+) but not Beta lactamase organisms.
In which one of the following clinical situations is the prophylactic use of antibiotics NOT warranted?
A. Preventions of meningitis among individuals in close contact with infected pts
B. Pt with a hip prosthesis who is having a tooth removed
C. Presurgical treatment for implantation of a hip prosthesis
D. Pt who compains of frequent respiratory illness
E. Presurgical treatment in GI procedures
D- respiratory illness may be of viral origin and chronic disorders may not warrant prophylactic use of AB
Name the drug in 4th gen cephalosporin and explain its importance
Cefepime (maxipime) IV/IM
better gram (+) than 3rd gen and effective against bugs that have developed resistance to earlier generations of cephalosporins
An elderly diabetic pt is admitted to the hospital with pneumonia. The sputum culture stains for a gram(-) rod. The pt is started on IV ampicilin. Two days later, the pt is not imporving, and the microbiology lab reports the orgnism to be a B-lactamase-producing H.influenzae. What course of treatment is indicated?
A. continue IV ampicillin
B. switch to IV cefotaxime
C. switch to oral vancomycin
D. add gentamicin to the ampicillin therapy
B- cefotaxime (claforan) IV/IM 3rd gen for gram (-) and resistant to B-lactamase
Ampicillin is not resistant
vancomycin is for gram (+) serious infections
Name the gram (-) bacteria
Salmonella
Klebsiella
Helicobacter
Legionella
Escherichia
Spirochaetes
Neisseria
Shigella
Moraxella
Proteus
Hemophilus
Yersinia
Pseudomonas
Macrolides are the drug of choice for which illnesses?
Drug of Choice for “Atypical” Pneumonias:
Legionnaire’s disease (Azithromycin)
Mycoplasma pneumonia (erythromycin or tetracycline)
Chlamydia pneumonia
A pt with degenerative joint disease is to undergo insertion of a hip prostheis. To avoid complications dur to postoperative infection, the surgeon will pretreat this pt with an AB. This hospital has problems with MRSA. Which is adequate?
A. Ampicillin
B. Imipenem/cilastatin
C. gentamicin/piperacillin
D. Vancomycin
E. cefazolin
D. Vancomycin
none of the others can combat MRSA
Imipenem/cilastatin is a carbapenem
ampicillin and cefazolin (1st gen) do nothing
Describe the antibiotic MOA: Bactericidal
they cause the death of susceptible bacteria DIRECTLY (bacteriCIDAL- suiCIDAL)
identify the aminoglycosides
Gentamicin (Garamycin) (IM/IV)
Kanamycin (Kantrex) (IM/IV)
Neomycin sulfate (PO)
Streptomycin (IM)
Tobramycin (Nebcin) (IM/IV)
Amikacin (Amikin) (IM/IV)
Paromomycin (Humatin) (PO)
Diagnosis? Caused by what?
Yeast Vaginitis caused by low levels of microflora (superinfection)
what can you prescribe to a pt with pseudomembranous colitis caused by C. diff?
DOC is metronidazole (flagyl) then try vancomycin is all fails
A 30 year old male is diagnosed to be HIV +. His CD4+ count is 200 cells/cm and his viral load is 10,000 copies/mL. In addition to receiving antiviral therapy, which of the following is indicatd to protect him agaisnt pneumonia due to PCP (pneumocystis jiro-veci)?
A. trimethoprim
B. Ciprofloxacin
C. Co-trimoxazole (bactrim)
D. Clindamycin
C- Co-trimoxazole or Bactrim is = Sulfamethoxazole + trimethoprim
Describe 1st Gen Cephalosporins
Beta lactam ring
sensitive to lactamase
good gram + coverage
Indicated for: URI, OM, surgical prophylaxis
What are the Mechanism of Action (MOA) of antibiotics?
Bactericidal or Bacteriostatic
Identify the Carbapenems and their routes
Ertapenem (Invanz) (IV/IM)
Meropenem (Merrem) (IV)
Imipenem/cilastatin (Primaxin) (IM/IV)
Doripenem (Doribax) (IV)
Which Penicillans are more likely to cause a hypersensitivity reaction and why?
Natural Penicillans becuase it comes from a mold
If a pt tests positve for meningitis, which Ab is the DOC [drug of choice]? why?
Ceftriaxime (Rocephin) IV/IM because they can cross the CSF, longer half life and once a day dosing
(*or Cefotaxime (Claforan) IV/IM* but not once a day dosing)
Why are Penicillins not effective against some bacteria?
Some bacteria secrete penicillinase (betalactamse) that splits the beta-lactam ring** **
What makes 3nd gen cephalosporin so great?
longer duration of action, most effective against gram (-) and resistant to beta lactamase producing bacteria and **only cephalosporins to penetrate CSF **
Under what conditions would you prescribe a carbapenem?
If pt is not allergic to PCN and has an anaerobic bacteria
Quinolones indications:
Lower respiratory tract infections
Bone and joint infections
Infectious diarrhea
Urinary tract infections
Skin infections
Sexually transmitted diseases except gonorrhea
Which two sulfanomides produce a synergistic affect and good for gram negatives? Indicated for which gram (-)?
Sulfamethoxazole combined with trimethoprim.
-Trimethoprim is the Dihydrofolate (FAH2) reductase inhibitor
Indications:
UTI -
PCP (New name: Pneumocystis jiroveci ) - haemophilus
OM
Chronic bronchitis of COPD
What does this pt have?
Exfoliative Dermitis
Identify the picture?
Gram (+)
Name the 1st Gen cephalosporins and routes
Cefadroxil (Duricef) (PO)
Cephalexin (Keflex) (PO)
Cefazolin (Kefzol) (IM/IV)
What is Phenazopyridine? What is it used for?
Prescribed in conjunction with an Ab for UTI and is a topical (bladder) analgesic
Bacteriodes Fragilis is a negative gram obligate anaerobe of the gut. If a Pt comes in for an abdominal [or colorectal] surgery which AB can you prescribe? why?
Cefoxitin (mefoxin) IV/IM
great for (-) gram anaerobes and as a surgical prophylaxis
Why would you Rx Clindamycin (Cleocin)?
Reserved for serious to life-threatening infections that cannot be treated with other Ab like Bacteriodes fragilis.
Cleocin vaginal for bacterial vaginosis (BV) or
Cleocin topical for acne
** carries a high risk of getting pseudomembranous colitis due to C. diff***
OM in children is treated by a macrolide and a sulfa. Name the two drugs, brand name, administration and dosage form
sulfisoxazole + erythromycin = Pediazole (PO) suspension
Name the Monobactam/route and explain why it is so unique.
Aztreonam (Azactam) with a narrow spectrum (IV/IM)
- only covers **AEROBIC gram (-) **
- excellent for Pseudomonas Aeruginosa anaerobic/aerobic
- PCN allergy is not an absolute contraindication just use with caution
what are the adverse effects of cephalosporins?
simlar to PCN: hypersensitivity
Contraindicated if PCN reaction is urticaria or anaplylaxis
Name the natural Penicillans, brand and route
Penicillin G benzathine (Bicillin L-A) (IM)
Penicillin G potassium (Pfizerpen) (IV/IM)
Penicillin G procaine (IM)
Penicillin G sodium (IM/IV)
Penicillin V potassium (Pen VK) (PO)
Macrolides indications?
Pneumonia
Bronchitis
URI from Haemophilus influenzae
Sinusitis
OM
STDs
how are the sulfa drugs administered?
Microsulfon- PO
silver sulfadiazine (Silvadeen)- topical
sulfisoxazole (Pediazole)- PO
Sulfamethoxazole + Trimethoprim (Bactrim) - PO/IV
sulfamylon (Mafenide)- topical
sulfacetamide (sulamyd) - Opthalmic
What are the three basic shapes of bacteria?
Bacilli – Rod shape
Cocci – Spherical shape
Spirilla – Spiral shape
Name the tetracyclines, brand and route
Demeclocycline (Declomycin) (PO)
Tetracycline HCL (Sumycin) (PO)
Doxycycline (Doryx) (PO)
Minocycline (Minocin) (PO)
Tigecycline (Tygacil) (IV)
What does this pt have?
Toxic Epidermal Necrolysis (TEN)
When would you Rx Vancomycin PO?
Serious life-threatening Gram + infections resistant to PCN (i.e. MRSA)
Serious life-threatening Gram+ infections in PCN allergic patients
Enterococci (resistance developing)
Pseudomembranous colitis from C. Diff that’s resistant/relapsing from Flagyl
Which bacteria does not stain but is still classified as + gram and why?
Mycoplasma because it has no cell wall
Name the 3rd gen cephalosporins, brand and route
Cefpodoxime proxetil (Vantin) (PO) + **Ceftriaxone (Rocephin) (IV/IM) +**
Ceftibuten (Cedax) (PO) Cefditoren pivoxil (Spectracef) (PO)
Cefotaxime (Claforan) (IV/IM) +
Ceftazidime sodium (Fortaz) (IV/IM)
Cefdinir (Omnicef) (PO)
Cefixime (Suprax) (PO) +
+ Currently Approved for GC
MOA of cephalosporins?
Bacteriocidal
Superior to PCN
divided into 5 generations
How to antibiotics contribute to resistance?
AB kills the bacteria SENSITIVE to it–> the few MUTATED (insensitive to drugs) bacteria continue to multiply and infect
*AB do NOT cause mutations but contribute to its “selective pressure” on mutated microbes*
microbes follow an “adapt or die” theory
DOC for pregnant woman with gonorrhea?
cephalosporins 3rd generation bc best for gram (-)
Ceftriaxon (rocephin)
Ceftazidime sodium (Fortaz)
Cefotaxime (Claforan)
Cefpodoxime proxetil (Vantril)
Cefixime (Suprex)
Why do gram negative bacteria stain red?
Cell wall loses its stain or IS decolorized by ETOH
Name the types of Antibiotics.
Penicillins
Cephalosporins
Sulfonamides
Macrolides
Tetracyclines
Aminoglycosides
Quinolones
Miscellaneous
Name the sulfa drugs
Sulfadiazines
Sulfamethoxazoles
Sulfisoxazoles
Sulfacetamide
Sulfamylon
What do you see?
gram (-)
Identify
MRSA - Methicillin Resistant Staph Aureus
due to nosocomial infections
what are the two antibiotic spectrums of activity?
Narrow Spectrum and Broad Spectrum
What are sulfonamides used for?
Mostly UTI but other indications are:
PCP,Shigellosis, Prophylaxis
What are broad spectrum antibiotics?
antibiotics effective against a wide variety of infections
Which gram bacteria usually causes bacteremia?
(-) gram bacteria (Salmonella, Klebsiella, Helicobacter, Legionella, Escherichia, Spirochaetes, Neisseria, Shigella, Moraxella, Proteus, Hemophilus, Yersinia, Pseudomonas)
Which AB produces risk of tendon rupture? to which age population?
Quinolones
- to pts over 60 and increased if they are taking corticosteriods
- contraindicated to under 18 years old
Which drug is good for C. difficile-associated bacteria?
Macrolide- Fidaxomicin (Dificid) PO
Metronidazole (flagyl) or as a last resort Vancomycin
Carbapenems are contraindicated for which pts?
PCN allergic pts
Identify the Penicillinase-resistant AB and routes.
Dicloxacillin (PO)
Nafcillin (IV)
Oxacillin (Bactocill) (IM/IV)
quinolones is contraindicated for which pts and why?
kids under 18 due to risk of tendon rupture and pt with myasthenia gravis due to risk of exacerbation of muscle weakness
Which drug turns your urine bright orange? What else can the drug stain? How much should you prescribe?
- Phenazopyridine (Pyridium)
- May stain contact lenses
- Only prescribe enough for two days
Names the Macrolides, brand and Routes
Erythromycin base (Eryc) (PO)
Erythromycin ethylsuccinate (E.E.S.) (PO)
Erythromycin stearate (Erythrocin) (PO)
Azithromycin (Zithromax) (PO/IV)
Clarithromycin (Biaxin) (PO)
Erythromycin lactobionate IV (Erythrocin IV)
What is Pseudomembranous colitis? which drug carries a high risk of getting it?
Caused by bacterium Clostridium difficile (AKA C. diff colitis) due to an interruption of normal flora in colon
C. diff produces toxins → Severe diarrhea (may be bloody), High fevers, Abdominal cramping/pain, Prostration
caused by Clandamycin (Cleocin) PO/IV/IM
Name some sulfamethoxazole and its route of administration?
Bactrim and Septra (PO/IV)
How do bacteria develop resistance?
1-they can produce enzyme that deactivate the antibiotic
2-they can change cellular permeability to prevent the drug from entering the cell
3-they can alter transport systems to exclude the drug from active transport into the cell
4-they can alter binding sites on the membranes so they can no longer accept the drug
5-they alter binding sites on the ribosomes so they no longer accept the drug
6-they produce chemicals that act as an ANTOGONIST to the drug
Which are your fixed does Extended- spectrum penicillins?
Ticarcillin + clavulanic acid [inhibits penicillinase] = Timentin (IV)
Piperacillin + tazobactam [inhibits penicillinase] = Zosyn (IV)
Diagnose and give cause
Diaper Dermatitis from Candida (diaper rash from bacteria or yeast superinfection)
What drug causes the reaction on the picture? And what is it?
Caused by sulfonamides
Steven-Johnson Syndrome: Severe to life-threatening hypersensitivity complex that affects the skin & mucus membranes -May occur in response to an illness but MORE OFTEN occurs in response to a drug
Tetracyclines are the drug of choice for??
gram (-) Cholera, Rocky Mountain Spotted fever, Chlamydia, Lyme Disease
Pt has P. aeruginosa and is allergic to PCN, which AB is the drug of choice?
Aminoglycoside
Identify: Penicillan spectrum?
Kill a wide variety of bacteria → broad spectrum
AKA “beta-lactams”
If you want to prevent infections secondary to burns, which drug would you use ?
silver sulfadiazine (Silvadeen)- topical or Sulfamylon Topical (Mafenide) [similar action to sulfadiazine]
Which are your fixed dose Aminopenicillins?
Ampicillin + sulbactam [inhibits penicillinase] = Unasyn (IM or IV)
Amoxicillin + clavulanic acid [inhibits penicillinase] = Augmentin (PO)
Name Sulfadiazines antibiotics and routes
sulfadiazine (Microsulfon) PO
silver sulfadiazine (Silvadeen) Topical
MOA of tetracycline?
bacteriostatic
most administered PO except for Tygecyline (IV)
bind to ions ot form insoluble complexes
What do you see?
Neisseria gonorrhoeae
Gram Negative Intracelluar Diplococci
identify
Staphylococci
Which AB have a beta-lactam ring in the center?
Penicillins, cephalosporins, monolactams and carbapenems
Which drugs should** not** be** **given to pts with Mysthenia Gravis? (it’s contraindicated)
Quinolones and Ketolides- Telithromycin
When would you give a prophylaxis?
- if a Pt Travels to an area where an infectious disease is endemic
- before a GI or GU surgery
- for Known cardiac valve disease or prosthetic valves
- for Known exposure to life-threatening or chronic infection [meningitis, TB]
- before Invasive procedures
Pregnant woman tests positive for Chlamydia- which is the best treatment?
(Macrolide)Azithromycin bc Tetracycline may harm the fetus
Why do gram positive bacteria stain blue-violet?
Cell wall retains the stain or resists decolorization with ETOH
What is good to treat an eye infection? Give generic and brand name.
Sulfacetamide Ophthalmic (Sulamyd)
What color are gram negative bacteria when stained?
red
Which test requires culture taken from an infected site then grown out on a agar plate? and why would you do this test?
culture and sensitivity- demonstrates which drugs the microorganism is sensitive to therefore helps choose THE BEST DRUG - great way to test various drugs at one time
Why is 2nd Gen Cephalosporin better thn 1st gen?
Better gram (-) coverage, more potent , good coverage of anaerobic bateria
(-)Oxygen2 [(-) gram, lack Oxygen, 2nd gen]
What are super infections?
Superinfection are often caused by broad spectrum antibiotics or chronic long-term Ab use
Normal flora typically protects against pathogenic microorganisms but with antibiotics they are destroyed–> opportunistic microbes proliferate
A 25y/o male returns home from a holiday in the Far East and complains of 3 days of dysuria and a purulent discharge. You diagnose this to be a case of gonorrhea. Which of the following is an appropriate treatment?
A. Ceftriaxone IM
B. Penicillin G IM
C. Gentamicin IM
D. Piperacillin/tazobactam IV
E. Vancomycin IV
A- Ceftriazone IM (rocephin)
Most gonorrhea are resistant o PCN
gonorrhea is a gram (-) PCN G treat gram (+) and vancomycin is too strong
In general, what are the adverse affects of antibiotics?
SHRuGiN’
Superinfections
Hypersensitivity reactions
Renal toxicity
Gastrointestinal (GI) tract toxicity
Neurotoxicity
Which type of gram bacteria do carbapenems cover?
most beta lactamase gram + and gram - and anaerobic bacteria (including - Pseudomonas Aeruginosa anaerobic/aerobic)
Children younger than 8 years of age should not receive tetracyclines, because these agents:
A. cause rupture of tendons
B. do not cross into the CSF
C. are not bactericidal
D. deposit in tissues undergoing calcification
E. can cause aplastic anemia
D. deposit in tissues undergoing calcification
Quinolones cause ruptures of tendons
Which are your extended spectrum penicillins?
Ticarcillin
Piperacillin
what can you prescribe to a pt with chlamydia who is allergic to PCN ?
Azithromycin (best for PCN allergic pts)
Which AB can you give a pt with CF?
inhaled form of Azteonam (Cayston) [monobactam] or Tobramycin (Tobi podhaler) [aminoglycosides]
Which drugs cover Pseudomonas and which is the drug of choice?
DRUG OF CHOICE: Ceftazidime Sodium (Fortaz) but any of the following work too:
Ticarcillin [extended spectrum penicillin] IV
Aztreonam (Azactam) IV/IM
or any of the carbapenem: Meropenem (Merrem) IV, Imipenem/cilastatin (Primaxin) IM/IV, Doripenem (Doribax) IV but not ertapenam (invanz) IV/IM
or an Aminoglycoside
What is septicemia?
- also known as bacteremia
- is the presence of bacteria in the blood due to a failure of defense mechanisms
- life threatening condition w/ high mortality rate
- may progress to septic shock, multiple organ failure or death
Under what conditions would you not do a culture and sensitivity test?
if the pt already started taking antibiotics
What are the signs and symptoms for sepsis?
- either high temp (fever) or a low body temp
- leukocytosi >12,000 or leukopenia 10% bands (immature neutrophils)
- tachycardia
- Tachypnea
- vomiting
Name the gram (+) bacteria
Listeria
Staphylococcus
Streptococcus
Enterococcus
Clostridium
Corynebacterium
Mycoplasma *
What are some adverse effects to prescribing sulfonamides?
*Photosensitivity- sensitive to the sun
*Toxic epidermal necrolysis (TEN)
*Steven-Johnson Syndrome
*Exfoliative dermatitis
Crystalluria
Toxic nephrosis
Urticaria
Aplastic anemia
(*pictures on pharm slides*)
Describe the antibiotic MOA: Bacteriostatic
inhibits growth and reproduction of susceptible bacteria by causing death INDIRECTLY
What factors should a clinician take into account when prescribing antibiotics?
- identifying the right pathogen
- selecting a drug that is the most effective with the lowest side effect specific to the pathogen and pt
- least expensive drug
Pt who test positive for STD Chlamydia should get which AB?
Z-pack (microlide) or Tetracycline
What is the drug of choice for a pt with pseudomembranous Colitis?
Drug of choice is metronidazole (Flagyl) but if it fails then Vancomycin
What is the MOA of penicillans?
Bactericidal → Inhibit cell wall synthesis
Bind to the PCN-binding protein inside the bacteria cell wall and disrupting cell wall synthesis leading to cell lysis.
What does this pt have? Prob Caused by what?
Steven- johnson Syndrome probably caused by sulfonamides
Name the Ab whose adverse effect is ototoxicity and nephrotoxicity AND it’s signs.
Aminoglycosides:
Warning Signs of Ototoxicity-
Dizziness
Tinnitus
Hearing loss
Warning Signs of Nephrotoxicity
Urinary casts
Proteinuria
Elevated BUN and serum creatinine levels
Name the quinolones, brand and route
Ciprofloxacin (Cipro) (PO/IV)
Norfloxacin (Noroxin) (PO)
Ofloxacin (Floxin) (PO)
Gemifloxacin (Factive) (PO)
Levofloxacin (Levaquin) (PO/IV)
Moxifloxacin (Avelox) (PO/IV)
quinolones suffix is -floxacin
Which drugs are good for community acquired pneumonia (CAP)?
5th Generation cephalosporin- Ceftaroline fosamil (Teflaro) IV (also good for skin/skin structure infections)
and Ketolides- Telithromycin (Ketek) PO
Name the different types of Penicillins
Natural penicillins
Penicillinase-resistant penicillins
Aminopenicillins
Extended-spectrum penicillins
Define: antibiotics
medications used to treat infections by susceptible bacteria. (bacteria that are not resistant)
How can we prevent AB resistance?
Use it judiciously
Can antibiotics cause a synergistic affect? If so, Give an example.
Yes, when combined (1+1=5), some diseases require multiple antibiotic therapy (i.e.TB)
synergistic: Bactrim or Septra (PO/IV) = sulfamethoxazole + Trimethoprim
MOA of Macrolides
Bacteriostatic OR bacteriocidal
broad spectrum
used for PCN allergic pts
Which AB can you prescribe for a pink eye?
none - pink eye is viral
Which Penicillins have a bulky side group and what is it for? Is there a downfall to this bulky group?
Penicillinase- Resistant IOT protect the Beta lactam ring from penicillinases BUT it inhibits ability to penetrate gram (-)
What color are gram positive bacteria when stained?
Gram positive bacteria appear blue-violet on Gram stain
MOA of quinolones
Bactericidal
excellent oral absorption unlike aminoglycosides
covers both gram (+) and gram (-)
Pt has P. aeruginosa and is allergic to PCN, which AB is the drug of choice?
Aztreonam (Azactam)
A pt with a gunshot would to the abdomen, which has resulted in spillage of intestinal contents, is brought to the ER. Which AB would you select to effectively treat an infection due to Bacteriodes fragilis?
A. Aztrenam
B. clindamycin
C. gentamicin
D. Azithromycin
E. Doxycycline
B. Clindamycin
Which drug is good for toxoplasmosis?
Sulfadiazine (Microsulfon) - PO
Which AB is appropriate for a pt with mono and strep?
Any natural Penicillin, Cephalexin (keflex) PO (1st gen cepahlo with B-lactam ring) or erythromycin (macrolide- if pt is allergic to PCN) for the strep.
Mono is a virus (no AB for it) but if a pt also has strep, they will develop hypersensitivity to Ampicillan/Amoxicillan.
drug of choice is Cephalexin
Which drug would you use to treat malaria?
Sulfadiazine (microsulfon) - PO in conjunction with other drugs
Primary use of Penicillins are for which type of gram bacteria?
mainly Gram +
name the 2nd generation cephalosporins
Cefaclor (Ceclor) (PO)
Cefprozil (Cefzil) (PO)
Cefoxitin (Mefoxin) (IM/IV)
Cefuroxime axetil (Ceftin) (PO)
Cefuroxime sodium (Zinacef) (IM/IV)
Cefotetan (Cefotan) (IM/IV)
