Antibiotics Lecture 32

Question 1

Tetracycline 
Mechanism
Cidal or Static
Drugs
Treats 
Side Effects 
MOR 
Contra Indications

Answer 1

30S 
limited CNS penetration 
Static 
Tetracycline (1)
Doxycycline (fecally eliminated can be used in renal failure) 
Minocycline 

Burkholderia Pseudomallei 
Borrelia Burgdorferi (Lyme)
M. Pneumo 
Acne
Can get into cell 
Chlamydia
Rickettsia  (RMSF)

1. Discoloration of teeth and inhibition of bone growth in children (contraindicated in preg)
2. photosensitive
3. GI
4. renal problems with EXPIRED-faconi

MOR

1. Decrease uptake
2. Increase efflux

Do not take with milk , antacids, or iron containing divalent cations because it inhibits absorption in the gut

Question 2

What is the special super tetracycline derivative that doesn’t have MOR? What does it treat?

Answer 2

Tigecycline (glycylcycline)

1. Gram Positive
   -MRSA
   -VRE
   not for UTI or bacteremia~~
2. More activity against Gram negative
   - Not for Proteus or pseudomonas
3. Anaerobes
   - Bacteroides Spp

Question 3

Sulfonamides
MOA
Static or cidal
Toxicity

Answer 3

Inhibits dihydropteroate synthase

static

1. Hypersensitivity reactions
2. hemolysis if G6PD deficient
3. nephrotoxicity(tubulointerstitial nephritis)
4. photosensitivity
5. kernicterus in infants
6. displaces other drugs

Question 4

Trimethoprim
MOA
Static or cidal
Toxicity

Answer 4

Inhibits dihydrofolate reductase

static

TMP (treats marrow poorly) *
megaloblastic anemia
leukopenia
granulocytopenia

Question 5

TMP SMX
Static or cidal
Treats
MOR

Answer 5

cidal

• broader spectrum
• decreased emergence of resistance

Treats]

1. CA-MRSA
2. UTI
3. Bacterial Prostatitis*
4. Nocardia
5. Pneumocystis carinii
6. stenotrophomonas maltophilia

MOR

1. altered enzymes
2. decreased uptake
3. increase PABA

leukopenia, thrombocytopenia, hypersensitivity rash crystalluria, drug interactions

Question 6

Chloramphenicol
Mechanism
Static or Cidal 
Treats
Toxicity 
MOR

Answer 6

blocks peptidyl transferase at 50S

Static, except for:
H. flu
Strep Pneumo
Neis. Meningitidis

1. Meningitis in:
   - H. flu
   - N. meingidids
   - Strep Pneumo
2. Rocky mountain Spotted Fever
3. typhoid fever

-dose change renal failure

Toxicity:

1. Anemia
2. Aplastic anemia
3. Gray baby syndrome *

MOR:
1. inactivated by acetyltransferases

Question 7

Nitrofurantoin

Answer 7

-inhibits translation, bacterial respiration and pyruvate metabolism

MOR: E. coli-nitrofuran reductase

Acute Uncomplicated UTI *

Question 8

Methenamine

Answer 8

Formaldehyde *
suppressor or prophylaxis against recurrent UTI

-Not for urease producing proteus