ABX Paxton Pearls

Question 1

Oral contraceptives

Answer 1

Recommend back-up BC while on ALL abx

Rifampin is a potent CYP inducer

Question 2

Warfarin

Answer 2

Avoid concomitant use if possible or monitor INR more frequently.

INC INR:

1. all macrolides, TTC, FQ
2. Metronidazole (2-4x)*
3. TMP-SMX (2-4x)*

DEC INR:
1. rifampin*

Question 3

Dysrhythmia

Answer 3

1. macrolides (generally all agents); we hate this drug, it’s a drug of desperation
2. FQs

Question 4

Ototoxicity

Answer 4

1. AGs (gentamicin&raquo_space; vancomycin)
   - permanent sensorineural hearing loss
2. minocycline
   - transient vestibular dysfunction (dizziness, N/V)

Question 5

Nephrotoxicity

Answer 5

1. AGs –> acute tubular necrosis
   - gentamicin*
2. Vancomycin
   - problem combined w/other nephrotoxic agent or overweight pt
3. PCNs (nafcillin > piperacillin) & FQs (cipro)
   - AIN

Question 6

Hepatotoxicity (drug-induced liver injury)

Answer 6

1. Amox/Clav
2. TMP/SMX
3. INH > RIF = PZA

Top 10: 9 Abx and Diclofenac
Rash/fever or eosinophilia, onset 1-5 weeks

Question 7

Chemical Phlebitis

Answer 7

1. Nafcillin* - burning, do NOT give peripheral IV
2. Cefepime
3. Vancomycin
4. Clindamycin

Question 8

Disulfiram-Like Rxn

Answer 8

Reaction: NVD, abd cramps, flushing, tachycardia, HA

Metronidazole*, consider ETOH interaction

Question 9

Red Man/Neck Syndrome

Answer 9

Vancomycin*

Rapid infusion releases histamine (rate issue)

Flushing face, neck, upper torso; wheezing, hypotension possible

Tx: slow infusion and give diphenhydramine

Question 10

Red Lobster Syndrome

Answer 10

Rifampin*

Red-orange discoloration of urine, tears, sweat

Pt Ed is crucial

Question 11

Discolored teeth

Answer 11

TTCs

Darkening of developing teeth

C.I. in pregnant women/kids < 8

Question 12

Loss of red/green color perception

Answer 12

Ethambutol (high dose) –> optic neuritis

Question 13

Yellow baby syndrome

Answer 13

Sulfonamides*

Do not use in women near term or neonates

Question 14

K+ Dysregulation

Answer 14

1. Hyperkalemia
   Trimethoprim
   - blocks Na in distal nephron = impaired K excretion
   - TMP-SMX + ACEI/ARB/spironolactone INC risk of hospital admit

2. Hypokalemia
various PCNs (esp nafcillin)

Question 15

CDI

Answer 15

Highest prevalence

• PO aminopenicillins
• PO cephalosporins

Highest incidence
- clindamycin

Question 16

EBV

Answer 16

Diffuse MP, nonurticarial rash

Ampicillin (Mono)

Question 17

Pregnancy Category B

Answer 17

1. B-lactam
2. Macrolides (azithromycin)
3. Clindamycin
4. Fosfomycin
5. Nitrofurantoin - NOT allowed in the last month
6. Metronidazole - NOT first tri, only use short course
7. PO Vancomycin

Question 18

Pregnancy Category C

Answer 18

1. FQ
2. TMP-SMX
3. IV Vancomycin

Question 19

Pregnancy Category D

Answer 19

1. AG

2. TTC

Question 20

FAST abx & pregnancy

Answer 20

Fluoroquinolones - arthropathy?
Aminoglycosides - possible CN8 toxicity in fetus
Sulfonamides - newborn kernicterus
Tetracyclines - tooth/bone problem for infant

Question 21

Neurotoxicity - seizures

Answer 21

PCNs, CPHs, carbapenem

Question 22

Neurotoxicity - psychosis

Answer 22

Clarithromycin

Question 23

Neurotoxicity - insomnia

Answer 23

FQ

Question 24

Neurotoxicity - encephalopathy

Answer 24

Metronidazole