Antibiotic Drug Interactions

Question 1

TMP-SMX

Answer 1

Warfarin (Inc INR)

Question 2

Macrolides (E+C)

Answer 2

• inhibit CYP450 3A4 and 2C9
  (Theophylline, Carbamazepine, Valproate, Cyclosporine, Digoxin, Phenytoin, WARFARIN)

Question 3

Tetracyclines

Answer 3

Oral Chelation (absorption impaired by dairy products, Al, Ca, Mg, Fe, Zn, bismuth subsalicylate)

Question 4

Metronidazole

Answer 4

• Warfarin (Inc INR)
• Alcohol (disfuliram reaction)

Question 5

Daptomycin

Answer 5

Statins (could lead to increased myopathy)

Question 6

FQs

Answer 6

• Warfarin (inc INR)
• Oral Chelation (Zinc, Iron, Ca, Al, Mg) -> impairs oral absorption
• Cipro: 2C9-i (cyclosporine and theophylline)

Question 7

Linezolid

Answer 7

weak Monoamine oxidase inhibitor
- Increased risk of Serotonin Syndrome in pts using serotonergic agents (SSRIs)

Question 8

Cefmandole, Cefotetan, Cefmetazole, Cefoperazone, and moxalactam

Answer 8

Alcohol (disfuliram reaction) due to NMTT side chain

Question 9

Synercid

Answer 9

• CYP3A4-i (Inc Concentration of STATINS, cyclosporine, tracrolimus, and carbamazepines)