Antibiotics pt 3

Fluoroquinolones

100

MOA?

Inhibits bacterial topoisomerase (DNA gyrase)

200

Name 2 classes of antibiotics which exhibit reduced potency when taken with divalent cations

(1) Flouroquinolones

(2) Tetracyclines

300

Adverse Effects (4) : Flouroquinolones

(1) Torsades (what else?)

(2) GI distress

(3) Tendon rupture

(4) Teratogen

(Teratogen ⇒ Abnormal cartilage development)

400

In what age group are Flouroquinolones contraindicated?

<10

500

Name 2 factors which increase the risk of Flouroquinolone-induced tendon rupture

(1) Old age

(2) Glucocorticoids

TMP/SMX

100

MOA: Sulfamethoxazole

PABA analog ⇒ Inhibits dihydropterate synthase

PABA is the precursor molecule to folate

(PABA + Pteridine → → →  Folate. The initial reaction only occurs in bacteria)

200

MOA: Trimethoprim

Inhibits dihydrofolate reductase

300

What type of infections is TMP-SMX first line for?

(1) UTI

(2) Prostatitis

(3) Nocardia

(4) Pneumocystis jirovecci

(Prophylaxis for Toxoplasma, NOT treatment, which would be: combination of pyrimethamine and sulfadiazine, supported by leucovorin (folinic acid))

400

CD4: TMP-SMX prophylaxis against Pneumocystis jirovecci and toxoplasmosis

<200

<100

500

Adverse Effects - Renal, neonates, cutaneous, anemia, bleeding: TMP-SMX

renal:

(1) Type IV renal tubular acidosis

(2) Interstitial nephritis

neonates:

(1) Neural tube defects 

(2) Kernicterus

(Note: TMP-SMX ⇒ Neural tube defects due to ↓ folate levels)

cutaneous:

(1) Atopic reaction

(2) Steven-Johnson syndrome

(3) Photosensitivity

anemia:

(1) Pancytopenia ⇒ ↓ RBCs

(2) ↓ Folate ⇒ Megaloblastic anemia

(3) ↓ GSH ⇒ Hemolytic anemia

bleeding:

There is an increase in free Warfarin concentrate due to:

(1) Inhibition of CYP450 system

(2) Displacement from albumin

Metronidazole

100

MOA: Metronidazole

Free radical metabolites ⇒ DNA damage

(∴ Bacteriocidal)

200

As a general rule, compare when you would use Metronidazole vs. Clindamycin

In the treatment of ANAEROBIC bacteria,

(1) Metronidazole: Below the diaphragm

(2) Clindamycin: Above the diaphragm 

300

what does metronidazole treat in the setting of clostridium difficile

pseudomembranous colitis

400

Adverse Effect: Metronidazole

Disulfiram-like reaction

500

Quadruple therapy for H. pylori?

bismuth, doxycycline, metronidazole, PPI

Tuberculosis

100

What are the two phases of treatment for tuberculosis?

(1) 4 drugs for 2 months

(2) 2 drugs for 4 months

200

What drug regimen is most commonly used to treat active tuberculosis?

(1) Rifampin

(2) Isoniazid

(3) Pyrazinamide

(4) Ethambutol

300

MOA: Isoniazid

Inhibits the synthesis of mycolic acid

400

Resistance and adverse effects to isoniazid

Resistance:

Downregulation of Kat G (Kat G ≡ catalase-peroxidase)

AE:

(1) Vitamin B6 Excretion (Co-administer Vitamin B6 to prevent peripheral neuropathy)

(2) ⇒ Peripheral neuropathy

(3) Seizures

(4) Hepatotoxicity (liver acetylation, increased AST)

(5) Drug induced lupus

(6) Inhibits CYP450 

(INH = Injury to Nerves and Hepatocytes) 

500

Which antimycobacterial agent is a potent inducer of CYP450?

rifampin

Tuberculosis pt 2

100

MOA: Rifampin

Inhibits DNA-dependent-RNA polymerase

200

When can Rifampin be used as a monotherapy?

PROPHYLAXIS for those exposed to:

(1) Neisseria meningitis

(2) Haemophilus influenzae

300

Which drug can turn bodily fluids orange?

Rifampin

400

MOA and AE: Ethambutol

Inhibits arabosyl transferase ⇒ inhibits carbohydrate polymerization

AE: OPTIC NEURITIS

500

Which antimycobacterial agent may precipitate gout attacks?

Pyrazinamide