Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > Antimicrobials > Flashcards

Antimicrobials Flashcards

1
Q

Beta-Lactam Antibiotics:

Penicillins

A

contain a beta-lactam ring as part of their structure

bactericidal against susceptible MO by blocking bacterial transpeptidase, an enzyme that cross-links polymers of bacterial cell wall

typically used to treat susceptible strep and staph infections

bacteria have developed beta-lactamase enzymes, leading to the development of combo meds containing a beta-lactamase inhibitor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Penicillins: ADME

A

A: variable absorption; sometimes food affects absorption

D: wide distribution, inc. CSF

M: minimal liver metabolism (except nafcillin/oxacillin, which have hepatic metabolism)

E: rapid and extensive renal elimination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Penicillins: Patient Education

A

Women on BCP should use alternative method until next period, or at least for one week after abx course complete

GI side effects common, esp. diarrhea

Ideally taken on an empty stomach

Finish entire course of abx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Beta-Lactam Antibiotics:

Cephalosporins

A

Similar mechanism of action to PCNs, but more stable to many beta-lactamases, and therefore are broader spectrum

General rule of thumb: later generations have better gram negative coverage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Cephalosporins: ADME

A

A: variable absorption; rate but not total extent affected by food, so may be taken with or without

D: wide, inc. to CSF

M: minimal metabolism, except cefpodoxime is de-esterified in GI tract to active form

E: high percentage excreted in urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cephalosporins: Patient Education

A

Most common side effects are GI

Cross-sensitivity with PCN allergy ranges from 2-12% in studies (give if mild allergy to PCN like rash without urticaria; avoid if severe allergy to PCN)

Ceftriaxone should not be used in premature neonates (can compete with bilirubin for binding sites and result in kernicterus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Types of Beta-Lactam Antibiotics

A

Penicillins, Cephalosporins, and Carbapenems (used in acute care setting only, broad spectrum, typically not first-line agents)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Examples of First Generation Cephalosporins & Common Uses

A

Cephalexin (Keflex), Cefadroxil (Duricef), IV Cefazolin (Ancef)

Often used for simple skin & soft tissue infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Examples of Second Generation Cephalosporins & Common Uses

A

Cefuroxime (Ceftin), Cefaclor (Ceclor), Cefprozil (Cefzil)

Often used as an alternate choice for URI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Examples of Third Generation Cephalosporins & Common Uses

A

Cefpodoxime (Vantin), Cefixime (Suprax), IV Ceftriaxone (Rocephin), IV Ceftazidime (Fortaz or Tazicef), IV Cefotaxime (Claforan or Cefotan)

Part of most protocols for CAP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Examples of Fourth Generation Cephalosporins & Common Uses

A

IV Cefepime

Clinical role similar to that of third generation cacapabilities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Vancomycin

A

bactericidal for susceptible gram positive bacteria by inhibiting bacterial cell wall synthesis

po form used to treat C Diff if metronidazole is ineffective

very poor oral absorption, results in no detectable serum level

IV dosing requires monitoring levels and adjustment for patient size and renal function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Examples of Tetracyclines

A

Vibramycin, Tetracycline, Doxycycline, Minocycline, Demeclocycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Tetracyclines

A

four ring chemical structure

bacteriostatic by entering MO (in part by active transport and in part by passive diffusion) and binding to 30s subunit of bacterial ribosome, interfering with protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Tetracyclines: ADME

A

A: divalent cations (calcium, magnesium, iron) bind to drug and inhibit absorption

D: highly protein bound; widely distributed, EXCEPT for CSF

M: concentrated by liver in bile and feces

E: all (except doxycycline) extensively renally excreted as unchanged drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Tetracyclines: Patient Education

A

Potential for increased photosensitivity

GI side effects common- take with food

Should not be given to children 8yr or younger (binds to calcium deposits in bone/teeth, causing deformity of bone, tooth enamel dysplasia); avoid in pregnancy for same reason

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Examples of Macrolides and Common Uses

A

Erythromycin, Clarithromycin (Biaxin), Azithromycin (Zithromax)

Firstline in many CAP protocols (generally have good coverage versus atypical bacteria; staph/strep coverage based on local susceptibility patterns)

Treatment of STIs (chlamydia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Macrolides

A

macrocyclic lactone ring

bacteriostatic at low concentrations, but bactericidal at higher concentrations

inhibit protein synthesis via binding to 50s ribosomal subunit

*caution in patients with baseline prolonged QT or on other meds that prolong QT (erythromycin and clarithromycin worse than azithromycin)

azithromycin has long half-life (48-96hrs) allowing for shorter abx course (stays in system) due to extensive tissue penetration (exceeds serum concentration; slowly releases from tissues)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Macrolides: ADME

A

A: clarithromycin and azithromycin more readily absorbed than erythromycin

D: wide, EXCEPT for CSF

M: CYP450 inhibitors; extensive hepatic metabolism

E: < 10% excreted unchanged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Telithromycin (Ketolide class)

A

structurally related to macrolides

binds to ribosomal subunit 50s to inhibit protein synthesis

second or third line against CAP

hepatoxicity, loss of consciousness, and visual disturbances are serious side effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Examples of Fluoroquinolones and Common Uses

A

ciprofloxacin (Cipro), moxifloxacin (Avelox), levofloxacin (Levaquin)

CAP (levofloxacin & moxifloxacin)
UTIs (NOT moxifloxacin; use cipro or leva)
Skin/soft tissue infections
Osteomyelitis (cipro- better bone penetration)

22
Q

Fluoroquinolones

A

bactericidal by blocking bacterial topoisomerases which prevents relaxation of coiled DNA that is required for normal bacterial transcription

newer quinolones have better gram positive coverage=respiratory FQs (levaquin, avelox)

older quinolones were developed for gram negative activity (cipro)

mechanism of quinolone resistance developed- point mutations in quinolone binding region, also change in permeability of organism

  • may cause significant QT prolongation (avelox more than levaquin)
  • may cause altered glycemic control
23
Q

Fluoroquinolones: ADME

A

A: excellent po absorption (80-95%); divalent cations (Mag, Ca+, iron) inhibit absorption

D: wide

M: minimal hepatic metabolism except moxifloxacin, which has extensive hepatic metabolism

E: other than moxifloxacin, extensive renal excretion (must dose adjust for CrCl <50)

24
Q

Fluoroquinolones: Patient Education

A

Caution for CNS ADRs such as dizziness, confusion, somnolence

Potential for phototoxicity

Not used in pediatric patients, other than in those with cystic fibrosis (due to arthralgias/joint swelling risk)

25
Q

Examples of Aminoglycosides and Common Uses

A

Garamycin, Gentamicin, Neomycin, Tobramycin

mostly used in acute care setting

26
Q

Aminoglycosides

A

dosing and therapeutic drug monitoring necessary; adjust for patient size/renal function

nephrotoxicity- highest risk with prolonged use/concomitant nephrotoxin administration

ototoxicity (8th cranial nerve)

27
Q

Types of Sulfonamides and Common Uses

A

Zonisamide (Zonegran), Sulfamethoxazole/Trimethoprim (Bactrim or Septra or TMP)

UTI, otitis media, traveler’s diarrhea, sinusitis

28
Q

Sulfonamides

A

bacteriostatic

mimics PABA which is required in order to form dihydrofolic acid; prevents nucleic acid formation

29
Q

Sulfonamides: ADME

A

A: agent specific

D: wide, inc. CSF

M: all have some element of hepatic metabolism

E: parent drug and inactive metabolites excreted (reduce dose in renal dysfunction or choose a different agent)

30
Q

Sulfonamides: Patient Education

A

photosensitivity

GI side effects; ideally taken on an empty stomach, but okay to take with food for GI upset

adquate hydration to prevent crystaluria

severe but rare: blood dyscrasias (contraindicated in patients with G6PD deficiency- may present with jaundice, purpura, or sore throat)

31
Q

Linezolid (Oxalodinone class)

A

treatment of MRSA/VRE

binds to 23s ribosomal RNA of the 50s subunit and interferes with protein synthesis

32
Q

Linezolid: ADME

A

A: complete po absorption

D: approx 30% protein bound, distributes into well-perfused tissues

M: liver oxidation

E: 30% unchanged in urine

33
Q

Linezolid: Patient Education

A

ADRs include: GI side effects, headache

Serious ADRs include: myelosuppression, neuropathy (with long courses may give vitamin B6/pyridoxine supplement to help prevent)

this drug is an MAO inhibitor, and may react with SSRIs and other agents that depend on MAO for metabolism (consider DC other MAOIs or SSRIs during treatment)

avoid foods high in tyramine (cheese, wine, beer)

34
Q

Clindamycin

A

binds to 50s ribosomal subunit of susceptible organisms inhibiting protein synthesis (similar to macrolides)

highly protein bound with wide Vd, but does not penetrate CSF well enough to use to treat CNS infections

35
Q

Clindamycin: Common Uses

A

used for strong anaerobic coverage, but covers mixed infections as well

used in aspiration PNA protocols

penetrates well into abcesses (staph)

36
Q

Clindamycin: Patient Education

A

common GI side effects

may cause antibiotic-associated colitis

37
Q

Metronidazole

A

mechanism of action not well understood, but interferes with bacterial DNA synthesis

adjust in severe hepatic disease

good tissue penetration

38
Q

Metronidazole: Patient Education

A

Disulfuram reaction (vs ETOH)- avoid all alcohol, even from cold medications

may cause darkening of urine (no concern unless volume of urine decreases)

39
Q

Metronidazole: Common Uses

A

used for anaerobic coverage

covers certain gram negative and gram positive organisms

used for bacterial vaginosis, trichomonal vaginitis (treat both partners), C Diff infecctions, and other GI infections

40
Q

Nitrofurantoin

A

used exclusively for UTIs, as therapeutic concentrations achieved ONLY in urine

inactivates bacterial ribosomal proteins

excreted through kidneys and not recommended for CrCl < 50-60 (drug loses effectiveness- less gets to site- and toxic effects are increased- lower excretion rate)

41
Q

Examples of Azole Antifungals and Common Uses

A

ketoconazole, itraconazole, fluconazole, voriconazole, posaconazole

vaginal or cutaneous candidiasis, tinea infections, onychomycosis, systemic fungal infections (step-down from heavy IV antifungal therapy- use ID specialist)

42
Q

Azole Antifungals

A

increased use has led to more resistant strains, esp in people with heavy usage of azole antifungals

work by reducing ergosterol synthesis by inhibiting fungal CYP450 enzymes (also cause human CYP450 interactions)

43
Q

Azole Antifungals: Patient Education

A

look up drug interactions!

LFTs must be assessed prior to, starting, and throughout course (unless short course in otherwise healthy person)

avoid in pregnant women and nursing mothers

elderly patients more susceptible to hepatic effects, and may require lower doses for renal function as well

44
Q

Examples of Adamantanes and Common Uses

A

Amantadine & Rimantidine

specifically inhibit replication of influenza A viruses, but not B; currently not being used for flu treatment due to recent CDC recommendation on resistant virus strains

now used for Parkinsons/movement disorders

45
Q

Antivirals: Adamantanes

A

interfere with influenza A virus M2 protein, leading to virus uncoating and therefore inhibition of viral replication and decreased viral shedding

work for movement disorders due to CNS effects

46
Q

Adamantanes: Patient Education

A

GI and CNS (anticholinergic) effects

caution in elderly, consider dose adjusting

teratogenic

psychological- can cause worsening of mental illness

47
Q

Antivirals: Neuraminidase Inhibitors

A

block the active site of influenza viral enzyme neuraminidase, which reduces number of viruses released from infected cell

works on influenza types A and B

48
Q

Examples of Neuraminidase Inhibitors & Common Uses

A

Zanamivir (Relenza)- inhaled powdered drug approved for age 7 and older for flu treatment and age 5 and older for flu prophylaxis

Oseltamivir (Tamiflu)- capsule or oral suspension for treatment or prophylaxis of flu in ages one and up

49
Q

Neuraminidase Inhibitors: Patient Education

A

Be careful with Tamiflu in children- post marketing research shows increased incidence of self-injury and delirium in children; teach parents to watch for unusual behavior

must use within 48 hours of symptom onset

decreases s/sx by one day, but more importantly decreases viral shedding, so less risk of spreading

ADRs include GI effects, and in zanamivir, bronchospasm precipitation

NOT a substitute for vaccination

50
Q

Herpes Antivirals

A

Acyclovir, Valacyclovir (prodrug of acyclovir), famciclovir (prodrug of penciclovir)

suppressive, not curative

phosphorylated by viral thymidine kinase (resistant strains often lack) and inhibit DNA polymerase and thus formation of viral DNA

Pharmacology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions