Antimicrobials Skibidi

what is spectrum?

how many classes of bacteria the abx is useful against

what does narrow spectrum mean?

only effective against 1 class

what does broad spectrum mean?

effective against a range of bacterial classes

what does bacteriostatic mean?

growth and replication of bacteria is stopped

what abx are considered bacteriostatic?

macrolides: azithromycin, clarithromycin, erythromycin
oxazolidinones: linezolid
lincosamides: clindamycin
tetracyclines: doxycycline
sulfonamides: sulfamethoxazole

what does bactericidal mean?

drug kills the bacteria

what abx are considered bactericidal?

aminoglycosides: tobramycin, gentamicin
beta-lactams: PCN, cephalosporins, monobactams, carbapenems
fluoroquinolones: ciprofloxacin, levoflaxacin, moxifloxacin
glycopeptides: vancomycin
metronidazole

what does resistance mean?

abx begins to not work against bacteria

why might a bacteria be resistant to a drug?

mutation of bacteria, adaptation, gene transfer

what are possible side effects of antibiotics?

allergic, toxic or idiosyncratic

what is the synergistic effect?

combination of different abx to have greater effects

why do you culture bacteria?

to properly identify in order to prescribe abx

what do cell wall inhibitor abx do?

inhibit cell wall synthesis of bacteria

what are beta lactams?

abx that contain a beta lactam ring and inhibit cell wall synthesis

what abx classes are beta lactams?

-penicillins
-cephalosporins
-carbapenems
-monobactams

what are the route of administration for penicillin G, PCN V, Benzathine pen G?

-penicillin G (IV)
-PCNV (PO)
-benzathine pen G (IM)

what is the spectrum of penicillin G, PCN V, Benzathine pen G?

narrow spectrum: Gm+ (Staph, Strep, Enterococcus)

what is penicillinase?

enzyme that breaks down beta lactam ring in PCNs

what is penicillin G, PCNV, or Benzathine pen G sensitive to?

penicillinase

what is the spectrum of amoxicillin and ampicillin?

broad; some Gm - activity

what is amoxicillin and ampicillin sensitive to?

penicillinase

what are amoxicillin and ampicillin combined with to overcome their sensitivity to penicillinase?

β- lactamase (penicillinase) inhibitors

what are the β-lactamase inhibitors?

-clavulanic acid
-sulbactam
-tazobactam

what is augmentin?

amoxicillin + clavulanic acid (PO)

what is the spectrum of nafcillin, cloxacillin, dicloxacillin, and oxacillin?

narrow spectrum Gm+ (Staph, Strep)

what is the route of administration for nafcillin, cloxacillin, dicloxacillin and oxacillin?

IV formulation (except dicloxacillin)

what are nafcillin, cloxacillin, dixloxacillin and oxacillin resistant to?

penicillinase

what is the spectrum of piperacillin, mezlocillin, ticarcillin?

not effective against Gm+, active against pseudomonas

what is piperacillin sometimes combined with for an empiric therapy against sepsis?

piperacillin-tazobactam (Zosyn)

what is the MOA of penicillins?

inhibit cell wall synthesis

what are SE of penicillins?

allergic rxn that can be fatal

how are penicillins eliminated?

kidneys

since penicillins are eliminated by the kidneys, what do you have to do?

dose adjust (except nafcillin and oxacillin- hepatic)

what is the MOA of cephalosporins?

cell wall inhibitors

how many generations of cephalosporins are there?

4 (technically 5)

what is the spectrum of 1st generation of cephalosporins?

narrow spectrum: good MSSA, some Gm-

what are 1st generation cephalosporins usually used for?

skin and soft tissue infection, unless suspect MRSA

what are examples of 1st generation cephalosporins?

-Cefazolin (Ancef) IV
-Cephalexin (Keflex) PO

what is the spectrum of 2nd generation cephalosporins?

increased activity against Gm-, weaker MSSA

what are examples of 2nd generation cephalosporins?

Cefaclor (Ceclor), Cefuroxime (Ceftin)

what is 2nd generation cephalosporins largely replaced by?

3rd generation because they have more broad coverage

what is the spectrum of 3rd generation cephalosporins?

more broad spectrum

what are 3rd generation cephalosporins resistant against?

β-lactamases

what is an example of an IV/IM 3rd generation cephalosporin?

Ceftriaxone (Rocephin)

what is an example of PO 3rd generation cephalosporins?

-Cefpodoxime (Vantin)
-Cefixime (Suprax)
-Cefdinir (Omnicef)

what is the spectrum against 4th generation cephalosporins?

Gm+ and Gm-, pseudomonas

what is an example of an IV 4th generation cephalosporin?

Cefepime which is used empirically for sepsis

patents who are allergic to PCN also have a 1% chance to be allergic to what?

1st and 2nd generation cephalosporins

what are examples of carbapenems?

-imipenem
-doripenem
-ertapenem
-meropenem

what is the spectrum of carbapenems?

broadest spectrum of β-lactams

what are carbapenems reserved for?

more-severe infections or failed tx

what is imipenem usually administered with and why?

cilastatin to prevent it being broken down into a toxic metabolite in the kidneys

what is the monobactam?

aztreonam (azactam) IV/IM

what is the spectrum of monobactam?

narrow spectrum, aerobic Gm-, psuedomonas

what is the monobactam resistant to?

beta lactamases

what is the most common side effect of monobactams?

cough

what are other serious side effects of monobactams?

-chest pain
-abdominal pain
-elevated LFTs
-TEN
-neutropenia

what is an example of glycopeptide?

Vancomycin (IV,PO)

what is the spectrum of glycopeptides?

Gm+

what is the only indication for oral vancomycin?

C. diff

what are the side effects of glycopeptides?

-ototoxicity
-nephrotoxicity
-red man syndrome

what is the route of administration for bacitracin?

topical

what is the MOA of bacitracin?

inhibits cell wall synthesis

what is the SE of bacitracin?

-contact dermatitis
-nephrotoxicity (PO)

what are examples of aminoglycosides?

gentamicin, tobramycin

what is the route of administration of aminoglycosides?

IV, ophthalmic

what is the MOA of aminoglycosides?

inhibit microbial protein synthesis

what is the spectrum of aminoglycosides?

broad, little activity against anaerobes

what are SE of aminoglycosides?

-ototoxicity
-nephrotoxicity
-neuromuscular toxicity

what are examples of tetracyclines?

tetracycline, doxycycline

what is the MOA of tetracyclines?

inhibits protein synthesis

what is the spectrum of tetracyclines?

broad; Gm-, Gm+, anaerobes

what are tetracyclines used to treat?

rocky mountain spotted fever and Lyme

what are SE of tetracyclines?

-teeth discoloration (<8yo, pregnancy, prolonged therapy)
-slow bone growth
-photosensitivity

what is a patient education point for tetracyclines?

don't take with antacids

who are tetracyclines not recommended for?

children or pregnancy

what are examples of macrolides?

-erythromycin
-clarithromycin
-azithromycin

what is the MOA of macrolides?

inhibits protein synthesis by binding to the 50S subunit of bacterial ribosome

what is the spectrum of macrolides?

broad; Gm+ and some Gm-, mycoplasma, legionella, STIs

what are SE of macrolides?

GI upset

what is the half life for azithromycin?

~3 days (long)

what are other protein synthesis inhibitors?

-linezolid (Zyvox)
-clindamycin

what is the spectrum of linezolid?

aerobic Gm+

what is linezolid reserved for?

vancomycin resistant infections

what is clindamycin used for?

skin and soft tissue infections

what are SE of clindamycin?

GI upset, C. diff

what are examples of folate antagonists?

-sulfamethoxazole
-trimethoprim

why are sulfamethoxazole and trimethoprim used together?

synergistic result

what is the brand name of trimethoprim/sulfamethoxazole (TMP/SMX)?

Bactrim

what is the spectrum of folate antagonists?

Gm+, Gm-, MRSA, listeria

what are SE of folate antagonists?

rash/uticaria, GI upset, thrombocytopenia

where are folate antagonists eliminated?

kidney

since folate antagonists are eliminated in the kidney, what must you do?

dose adjust for renal impairment

what are examples of fluoroquinolones?

-ciprofloxacin (cipro)
-levofloxacin (levaquin)
-moxifloxacin (avelox)

what is the MOA of flouroquinolones?

inhibits DNA synthesis

what is the spectrum of flouroquinolones?

broad

what are flouroquinolones commonly used for?

GU, respiratory, GI infections

what is the warning on fluoroquinolones and why?

black box warning, tendinitis and tendon rupture

what is flouroquinolone now recommended for?

patients with no other alternatives

what are the tuberlocosis medications?

-isoniazid
-rifampin
-pyrazinamide
-ethambutol
-dapsone*