Week 10 Antibiotics Flashcards
First-generation cephalosporins are active against which organisms?
First-generation cephalosporins are active against gram-positive cocci, including
S. aureus and S. epidermidis (excluding methicillin-resistant strains), and most
streptococci.
Why is there often cross-sensitivity and cross-resistance between penicillins and cephalosporins?
Due to the fact that both drug classes contain structurally similar side chains and beta lactam ring.
Doxycycline is not used during pregnancy because it may cause which effect in neonates?
Doxycycline, a tetracycline, is not used during pregnancy because it may cause discoloration of deciduous teeth in neonates.
A 33-year-old pregnant female patient has developed community-acquired pneumonia (CAP). Which antibiotic is most appropriate for this patient?
erythromycin or azithromycin is the first choice because each is Pregnancy Category B
A 42-year-old pregnant female patient comes to the clinic with an outbreak of herpes simplex to the lips. Which medication would be most appropriate for the patient?
Acyclovir is Pregnancy Category B and safe to use in pregnancy.
A 46-year-old patient is newly diagnosed with hepatitis C. The APN understands that hepatitis B serum will need to be drawn prior to starting any hepatitis C virus (HCV) medications for which reason?
There is a risk of reactivation of hepatitis B, and this would need to be covered.
Which of these is first-line therapy for a mild case of impetigo, with fewer than five 2-cm lesions on the left leg of a 10-year-old patient?
First-line therapy for impetigo is mupirocin unless it is a moderate to severe case.
Mupirocin is bactericidal and has a wide range of coverage against gram-positive bacteria, including methicillin-resistant S. aureus, and a limited coverage against some gram-negative organisms. Mupirocin acts by which mechanism?
Mupirocin is bactericidal at concentrations achieved by topical administration of the 2% ointment. Mupirocin acts by binding to bacterial isoleucyl-tRNA synthetase.
What is the difference between facultative & obligate?
Obligate truest sense of the term
Obligate aerobe has to have oxygen, If the oxygen drops a little bit the bacteria start to die
Obligate anaerobe: poisoned by oxygen
Facultative: in-between “gray scale”
Facultative anaerobic “prefers no o2” but can still survive
What 2 bugs should come to mind when you think of gram +?
Strep & Staph
What bug comes to mind when you think of gram negative?
e. coli
Bacterio-static:
slows cell from growing a multiplying…drug keeps growth slow so immune system can clean up mess
Bacteri-cidal:
KILLS the cells think for immunocompromised patients
What are the bacteriocidal mechanisms of action?
Cell wall synthesis inhibitors “open up cell wall guts spill out*
DNA synthesis inhibitors *stop dna from replicating = death”
Metabolic synthesis inhibitors “need metabolism for energy = death”
What are the bacteriostatic MOA?
Protein synthesis = usually static, at high doses»_space; cidal
What are the 4 ways bacteria become resistant to abx?
Change target: Abx targets bacteria, bacteria can change self so it doesn’t get detected
Influx Pumps: for bacteria to survive it can reduce influx pump (less abx gets into it)
Efflux Pumps: Increase efflux pump to pump abx out faster (less time for abx to work)
Enzymatic inactivation: Enzymes breakdown abx so bacteria survive attack and become resistant. Trait passed down to next generation of bacteria
Pt has positive strep and medical hx of PCN allergy…what do you give?
- What’s first line and can they take? If yes, stop thinking
- If not, 1st gen cephalosporin, Kephlex
What are the cell wall synthesis inhibitors?
PCN, cephalosporin (lactam abx) Vanco
Folic acid synthesis inhibitors (Metabolism Synthesis):
Sulfonamides & Trimethoprim (put together to form Bactrim)
Macrobid (Nitrofranitoin)
DNA Synthesis inhibitors:
Quinolones & Rifampin
Protein Synthesis inhibitors:
50S subunit: Macrolides & Clindamycin
30S subunit: Tetracycline
What inhibits the 50S subunit?
Macrolides & Clindamycin
Penicillin, Cephalosporins, & Glycopeptides (Vanco)
MOA
cidal or static?
Inhibit cell wall synthesis
Bacteriocidal
Penicillin
MOA 1st line 2nd line How to take ADR #3 Drug interaction #4 Pregnancy
MOA:
- inhibit cell wall synthesis; bactericidal
1st line: Syphilis and strep throat/pharyngitis
2nd line: lyme disease
How to take: empty stomach
Adverse Reactions:
Maculopapular rash w/MONO,
C. Diff,
Seizures,
Drug Interactions:
- Warfarin,
- diuretic,
- tetracycline,
- probenecid *
VERY SAFE IN PREGNANCY
Pen V
Narrow or Broad?
What bacteria does it cover?
What would you take it for?
(Very easy to take = oral) & Pen G (IV form) (natural PCN)
Very Narrow Spectrum = Gram + = strep including GABHS
Only cover strep
*When you have strep throat think natural Pen V
What makes PCN resistant unique?
Only PCN that covers STAPH AUREUS
(specifically Methicillin sensitive resistant SSA) & staph species
Staph has an enzyme that breaks down PCN EXCEPT penicillinase resistant
What inhibits the 30S subunit?
Tetracyclines
Protein synthesis inhibitors
What is PCN 1st line for? 2nd line?
1st:
Syphillis & strep throat/pharyngitis
2nd line:
-Lyme disease
What is Amoxicilline 1st line for? #4
2nd line? #2
1st line:
- Sinusitis
- Acute Otitis Media
- Endocarditis prophylaxis
- H. Pylori
2nd line:
- Lyme (Children <8yrs)
- CAP
What are 2 Augmentin indication?
Has beta-lactamase inhibitor that broadens anaerobic coverage…
COPD, CAP, Pregnancy UTI*
What type of bacteria have a lot of beta lactamase?
Anaerobic
What is Augmentin 1st line for?
Dog bites because of its anaerobic coverage
Which one is a Macrolide?
Clindamycin
Gentamycin,
Azithromycin
Vancomycin
Azithromycin and Erythromycin are macrolides
What does Macrobid treat?
Lower UTI for elderly
super concentrated in bladder
What is first line for Lyme disease? 2nd line?
Tetracycline (doxycycline)
2nd line: Amoxicillin (children <8yrs)
What are people with COPD prescribed?
Augmentin because it has anerobic coverage to cover the pus/mucus pockets
What are the characteristics of abx that cause c. Diff/
narrow spectrum & Gram + coverage
What are Cephalosporins MOA?
ADR? #3
Safe in pregnancy?
inhibits cell wall synthesis, beta lactam ring breaks down wall
Bacteriocidal
ADR: C. Diff Hemolytic anemia (rare) 10% cross sensitivity with PCN Maculopapular rash
Cephalexin (Keflex)
What generation?
1st line for?
Activity
Indication
1st gen cephalosporin “cepha”
**Think 1st gen mostly staph & strep”
LEAST TISSUE PENETRATION
Superficial
1st line
-Cellulitis (skin & soft tissue infection)
Activity:
-Gram +
MSSA, Strep, E. coli
Indication:
Cellulitis (99% staph or strep)
Impetigo (type of cellulitis)
Cefuroxime, Cefprozil, Cefaclor
What generation?
Activity?
Indication
2nd generation cephalosporin
Activity: Gram +
Indication:
-COPD Exacerbation (d/t more gram – coverage)
Ceftriaxone
Which generation? 1st line for? #2 Indication? #2 Contraindication ADR
3rd generation cephalosporin
1st line:
- Gonorrhea,
- meningitis (greatest tissue penetration)
Indication:
- Broader infection,
- URI
Contraindication:
-Neonates r/t hyperbilirubinemia 3rd gen
highly protein bound
ADR:
-pain at injection site
Vancomycin, telavancin (Vibativ) & dabavancin (Zeven)
What drug class? MOA PO indication? IV indication? 3 ADR Pregnancy?
Glycopeptide
MOA:
-Inhibits cell wall synthesis by binding to D-A1a-D-A1a portion,
Activity:
Narrow, only gram +
- PO cdiff,
- IV Vanco MRSA
- Watch out for: Red Man syndrome, nephrotoxic, ototoxic
- little absorption, safe in Pregnancy Category B
IV 1st line bacteremia MRSA, Pregnancy Category C
2nd line outpatient Clindamycin for pregnancy
5 Clindamycin fun facts
5 Fun facts: Very narrow spectrum, only gram + Great for MRSA Anaerobic Dental Infections Watch for C. Diff
Clindamycin
MOA Activity 1st line for? #3 Indications Contraindications? Side Effects #3 BBW #2
Lincosamides
Action: Protein Synthesis inhibitor (bacteriostatic) - 50S subunit,
Activity:
very narrow spectrum gram + & select, anaerobic coverage
Staph & strep
1st line: MRSA, PCN-allergic patients, PID
Indications: acne,
no absolute contraindications to clindamycin, well tolerated for everyone even renal
Side Effects:
- Macularpapular rash,
- GI,
- blood dyscrasia
BLACK BOX WARNING: colitis, C. diff infection
First line for cellulitis what do you think 1st & 2nd line?
1st gen. Cephalosporin (Keflex);
if there’s an anaphylactic allergy…2nd line Clindamycin
Bactrim tx which kind of infection?
UTI, gram – e. coli
How to treat MRSA?
CLINDAMYCIN: 1st line if you know it’s MRSA
BACTRIM: (covers e. coli & MRSA) = EMPIRIC
DOXYCYCLINE: MOST BROAD and anaerobic coverage
What is clindamycin BBW?
C. diff & colitis
Azithromycin, Clarithromycin, Erythromycin (ACE)
Drug class? 1st line for? #2 contraindications #2 Drug Interaction Side Effect #4
Macrolides
Activity:
Broad Spectrum, gram +/-, MSSA,
PERTUSSIS, Mycoplasma,
CHLAMYDIA , H. Pylori
1st line:
respiratory infections community acquired PNA (mycoplasma),
Pertussis,
Chlamydia in lungs,
Indication: Chlamydia, Pertussis, H. Pylori, chronic bronchitis
Contraindicated: AOM or sinusitis
Drug Interaction: All CYP450 inhibitors
Side Effect:
- watch for explosive, watery diarrhea
- QT prolongation/Torsade’s (take 2nd line Doxycycline)
- Watch liver
- Hypersensitivity (red man syndrome)
Always for pertussis even for less than 6 months even though could cause PYLORIC STENOSIS IN BABIES
What is the major indication/unique for Erythromycin
Bacterial conjunctivitis & topical acne
What are Clarithromycin’s indications #3?
COPD exacerbation, H. pylori, Pertussis
What 2 drug classes prolong QT?
Macrolides & Fluoroquinolones
3 most common abx for photosensitivity?
Bactrim, Flouroquinones, Doxycycline
Doxycycline, Minocycline, Tetracycline
MOA 1st line: #3 2nd line #1 ADR #2 Interactions
Tetracycline
«_space;a lot of resistance
Activity: Protein synthesis inhibitor – 30S, bacteriostatic very broad spectrum, anaerobic & atypical
Indication: MRSA (CBD oil) strep pneumo, mycoplasma, acne, tick borne ill ness 1st line: tick borne illness, acne 2nd line: CAP ADR: photosensitivity, GI,
Interactions:
- Back up birth control
- Milk & Calcium absorption (Doxy binds to calcium in teeth)
Pregnancy: NO
Peds: >8yrs
Ciprofloxacin, Levofloxacin “-floxacin”
ADR #3 BBW Contraindications #3 Education preg/lact 1st line for?
Fluoroquinolones
MOA: DNA gyrase inhibitor, bactericidal
Activity: very broad spectrum, especially gram – E.Coli, P. aeruginosa
Instruction: Take on empty stomach
ADR: GI,
phototoxic, tendinitis (rare),
tendon rupture (rare), skeletal muscle joint pain,
BLACK BOX WARNING: tendon rupture & tendonitis (cartilage abnormalities)
Contraindicated:
QT prolongation,
G6PD,
Myasthenia Gravis
Education: Report new onset pain, could be delayed by months
Pregnancy/Lactation: NO!
Elderly & Peds: as long as they can talk
1st line: serious/complicated infections = Pyelonephritis
3rd line: simple = CAP, UTI
Bactrim
MOA Activity Side Effect #5 Contraindication #3 pregnancy Education #3
1st line?
2nd line?
MOA: Folate Synthesis (Metabolism) inhibitor – bacteriocidal, Inhibits dihydrofolate synthetase
(Individually bacteriostatic/ together synergistic)
Activity: Broad Spectrum, E. Coli, MRSA, PCP* (polycystic PNA) «_space;opportunistic HIV infection
Side Effect:
- Kernicterus (brain damage),
- Crystalluria,
- Hypersensitivity,
- hemolytic anemia,
- photosensitivity
Contraindication:
- Pediatrics <2 months (kernicterus (hyperbilirubinemia) r/t undeveloped liver/brain)
- G6PD
- Sulfa Allergy
Pregnancy: NO
Education: stay hydrated, Sunscreen, Give folic acid supplement
1st line: UTI
2nd line: MRSA = Empiric Coverage “CBD oil”
What 3 abx cannot be taken with G6PD?
Bactrim, Nitrofurantoin, & Fluroquinolones
When do you have to start an antiviral after an outbreak?
within 72 hours
Ledipasvir/Sofosbuvir, Sofosbusvir/Velpatasvir
Indication
Monitor
BBW
*Always use 2 combo drug 12 weeks
Indication:
Hepatitis C
MOA: Inhibit HSV protein necessary for viral replication
Monitor:
Kidney,
bilirubin,
liver (treating virus in liver)
BLACK BOX WARNING: Hep B reactivation
How do you treat Hepatitis C?
Always need to know genotype
Oseltamivir (Tamiflu), Peramivir (Rapivab), Zanamivir (Relenza)
MOA
Monitor
ADR
Neuraminidase inhibitor
MOA: Neuraminidase Inhibitor = prevents virus from leaving the host cell so it can’t spread to other host cells
Monitor:
Renal fx
ADR: neuropsychiatric events (Caution in elderly),
Peds: >3months
- Start within 48 hours
- Works for influenza A & B
Zanamivir special monitoring? Bronchitis & SOB
Which medication for influenza is safe for lactation? Oseltamivir (Tamiflu)
Metronidazole
Indication: #5 ADR #5 Caution #2 Pregnancy BBW
Activity: Gram +/-, antiprotozoan (parasite), antifungal, anaerobes, antibacterial BROADEST OF THE BROAD
Indication: c. diff, bacterial vaginosis, H. Pylori (for PCN reaction), Trichomoniasis, PID
MOA: inhibits protein synthesis
ADR: GI, blood dyscrasia, CNS effects, metallic taste, dark urine
Caution:
Seizure threshold,
liver fx
Pregnancy: Avoid 1st trimester
Peds: OK
BLACK BOX WARNING: carcinogenic
