Antimicrobials

Question 1

Penicillin

Answer 1

Inhibits Pencillin binding protein (transpeptidase) which prevents cell wall cross linking (cell walls have a D-Ala-D-Ala structure), causing unstable cell walls and cell death

Gram +
N meningitidis
T pallidum

Penicillin V: oral, weaker form
Penicillin G: IV, IM

AA:
o IgE hypersensitivity reaction
o Interstitial nephritis
o Cross reactive with cephalosporins

Question 2

penicillinase-resistant penicillins

Answer 2

Naficillin, oxacillin, dicloxacillin, methicillin
pennicillinase resistant due to bulky R group

Staph aureus besides MRSA
o Osteomyelitis, myocarditis, soft tissue infections

Question 3

Amoxicillin, ampicillin

Answer 3

Penicillins with wider spectrum
pair with beta-lactamase inhibitors
H. influ
H. pylori
E. coli
Listeria
Proteus
Salmonella
Shigella
HHELPSS

AA:
rash in CMV
liver

Question 4

Pipercillin, ticacillin

Answer 4

anti-pseudomonal penicillins

Question 5

1st gen cephalosporins

Answer 5

cephalexin, cefazolin (flex, fez)
PEcK +
Proteus
E. coli
Klebsiella
gram positives

Question 6

2nd gen cephalosporins

Answer 6

cefaclor, cefoxitin, cefuroxime, cefotetan (fake fox fur tea parties)
HENS PEcK
	H. influ
	Enterobacter
	Neisseria
	Serratia

Question 7

3rd gen cephalosporins

Answer 7

ceftriaxone, cefotaxime, ceftazidime
serious gram - infections
meningitis
psuedomonas (taz covers naz)
gonorrhea
late stage Lyme

Question 8

4th gen cephalosporins

Answer 8

cefepime
broad spectrum
meningitis → crosses CSF
pseudomonas

Question 9

5th gen cephalosporins

Answer 9

ceftaroline
broad spectrum
MRSA
does NOT cover pseudomonas

Question 10

Carbapenems

Answer 10

-penem
beta-lactamase resistant
used in serious life-threatening side effects
broad spectrum
imipenem → adminster with cilastin to ↑ half life

AA:
serious side effects
CNS toxic (seizures)
GI distress
rash

Question 11

Aztreonam

Answer 11

monobactam
Beta-lactamase resistant
Aerobic gram negative rods
o Treats serious gram negative infections
 Sepsis, pneumonia, meningitis
o Pseduomonas
o Penetrates CSF

Question 12

Vancomycin

Answer 12

Inhibits cell wall synthesis by binding directly to D-Ala-D-Ala polypeptides
Bacterial resistance by changing their cell wall to D-Ala-D-LAC

IV
Treats MRSA and other multi-drug-resistant bacteria
S. epidermidis
C. diff → oral vancomycin

AA
o	Red man syndrome → flushing during infusion
o	Thrombophlebitis
o	Ototoxicity
o	Nephrotoxicity
	Excreted through kidneys
	Monitor plasma levels
o	DRESS syndrome → eosinophilia and systemic symptoms

Question 13

Daptomycin

Answer 13

Lipopeptide that disrupts cell membranes
MRSA and VRE
endocarditis
bacteremia

not effective vs pneumonia (surfactant inactivates daptomycin)

AA: rhadomyolysis, myopathy

Question 14

Tetracycline

Answer 14

doxycycline, minocycline
30S ribosomal binding
Tick born pathogens
	Rickettsia
	Ehrlichia
	Francisella
	Borrelia 

Zoonotic diseases
 Brucella
 Coxiella
 Yersinia

chlamydia
acne
MRSA

AA:
Contraindicated in pregnancy
teeth discoloration
inhibits bone growth
photosensitivity

Question 15

macrolides

Answer 15

(-thromycin)
50S ribosomal subunit inhibiting translocation
atypical pneumonia (M. pneumoniae, legionella, chlamydia)
Gram + infections in patients allergic to penicillin
B. pertussis

AA: MACRO
Motility (GI)
Arrhythmia
Cholestatic hepatitis
Rash
eOsinophilia

P450 inhibitor

Question 16

Clindamycin

Answer 16

50S ribosomal subunit inhibiting translocation
Gram + and anerobes
o	MRSA
o	Lung abscesses
o	Aspiration pneumonia
o	Bacteroides (oral infections)
o	Clostridium perfringens
o	Acne
o	Gardnerella vaginosis

Clindamycin above the diaphragm
Metronidazole below the diaphragm

paired with gentamicin for broad coverage

AA:
o Diarrhea
o C. difficile infections

Question 17

Chloramphenicol

Answer 17

Rarely used in the US
50S ribosome, inhibits translation
Bacteriostatic
Used in meningitis and rocky mountain spotted fever
Cheap 3rd world treatment of meningitis

Adverse reaction
o Anemia
o Gray baby syndrome
 Accumulation of drug due to lack of liver UDP-glucuronosyltransferase

Question 18

Linezolid

Answer 18

50S ribosome, bacteriostatic
Gram +
Staph, strep, enterococcus
MRSA and VRE (vancomycin resistant enterococcus)
Nosocomial pneumonia (MRSA)

Adverse reactions
o	Thrombocytenia 
o	Optic neuropathy
o	Peripheral neuropathy (glove and stocking)
o	Serotonin syndrome

Question 19

Aminoglycosides

Answer 19

gentamicin, neomycin, streptomycin, tobramycin, amikacin
30S ribosome, misreading mRNA causing cell death → bacteriocidal
Gram – bacilli, aerobes only
Coupled with beta lactams or vancomycins to help them get through cell wall
IV

Neomycin → bowel surgery prep
Streptomycin → tularemia, Y. pestis
Gentamicin and Tobramycin → severe, drug-resistant gram – rods
Amikacin → new, expensive, effective vs drug resistant

Adverse effects
o Nephrotoxicity
o Ototoxicity
o Neuromuscular blockade (myasthenia gravis is contraindication)
o Teratogen (contraindicated in pregnancy)

Question 20

Tuberculosis drugs

Answer 20

rifampin, isoniazid, pyrazinamide, ethambutol

4 drugs for 2 months, then 2 drugs for 4 months

Question 21

Isoniazid

Answer 21

Only agent that can be used by itself, iso → isolated
Latent TB
↓ mycolic acids in cell wall

Adverse effects
 INH → injures neurons and hepatocytes
 Drug induced SLE
 Vit B6 deficiency → administer with Vit B6
 Siezures
 P450 inhibition → ↑concentration of drugs

Question 22

Rifampin

Answer 22

Inhibits RNA synthesis
P450 stimulation → ↓concentration of drugs
Prophylactic monotherapy to close contacts of patients infected with H. influenzae or N. meningitidis

Adverse effects
 Orange body fluids
 Hepatotoxicity

Question 23

Ethambutol

Answer 23

↓ carb polymerization of cell walls by blocking arabinosyltransferase

Adverse reactions
 Optic neuropathy → red-green color blindness

Question 24

Pyrazinamide

Answer 24

Adverse effects
 Hyperuricemia → gout
 Hepatotoxicity → hepatic necrosis

Question 25

Mycobacterium avium treatment

Answer 25

* Azithromycin or clarithromycin * Ethambutol * Rifabutin → less potent stimulator of P450

Question 26

Mycobacterium leprae treatment

Answer 26

Tuberculoid form o Dapsone o Rifampin • Lepromatous form o Dapsone o Rifampin o Clofazimine

Question 27

Sulfonamides

Answer 27

Inhibits folate synthesis (dihydopteroate synthase) ``` Adverse reactions o Allergic drug reactions (Rash, fever, urticaria) o G6PD deficiency patients → hemolysis o Stevens-Johnson syndrome o Interstitial nephritis o Kernicterus in infants o Displace drugs from albumin (such as warfarin) o P450 inhibition ```

Question 28

Trimethoprim

Answer 28

Inhibits folate synthesis (dihydrofolate reductase) Trimethoprim + sulfamethoxazole = bactrim o 1st line treatment for UTI o Shigella o Nocardia o Pneumocystis jirovecii o Toxoplasma ghandii prophylaxis

Question 29

Fluorquinolones

Answer 29

-floxacins Inhibits DNA gyrase and topoisomerase, bacteriocidal gram - rods of UTI and GI o Complicated UTI’s (bactrim is first line) Some gram + Bacillus anthracis Otitis externa Divalent and trivalent metals decrease absorption Adverse effects o GI o Teratogenic o Tendonitis or tendon rupture

Question 30

Metronidazole

Answer 30

``` Forms free radicals that disrupt bacterial DNA Anaerobes below the diaphragm (clindamycin → above the diphragm) o C. diff o Clostridium Giardia Entamoeba Trichamonas Gardnerella ``` Adverse reactions o When taken with alcohol → flushing, tachycardia, hypotenstion o Metallic taste

Question 31

Amphotericin

Answer 31

Antifungal Binds to ergosterol, forms (TEARS) pores which leak electrolytes Serious, life threatening fungal infections o Mycoses o Mucor o Fungal meningitis Adverse reactions o Nephrotoxicity (almost always occurs) o Fever, chills, hypotension o Thrombophlebitis

Question 32

Nystatin

Answer 32

* Same as amphotericin | * Topical use for candidiasis

Question 33

Flucytosine

Answer 33

* Conversion of uracil to 5-fluoruracil inhibiting DNA and RNA synthesis * Systemic fungal infections * Cryptococcus

Question 34

Azoles

Answer 34

Inhibits ergosterol synthesis (lanosterol → ergosterol) by inhibiting P450 Antifungal Voriconazole o Aspergillosis o Candida Fluconazole o Candida o Cryptococcal meningitis Itraconazole o Dimorphic mycoses (2 Iterations) Clotrimazole and miconazole o Topical fungal infections (tinea) Adverse effects o Inhibits testosterone synthesis  Gynecomastia o Inhibits P450

Question 35

Terbinafine

Answer 35

inhibits squalene epoxidase | used for dermatophytoses