Anti-Infective - Drug Interactions

B-Lactams

• Probenecid (increased b-lactam serum concentrations)

• Vancomycin + puperacillin/tazobactam (increased risk for AKI)

• Carbapenems + valproate (significantly decreases valproate levels)

Macrolides

Cyp450 substrates and inhibitors (statins, calcium channel blockers, warfarin, tacrolimus, azoles)

• Azithromycin = minor substrate

• Clarithromycin = major substrate, potent inhibitor

Doxycycline

binds to cations (Ca2+, Mg2+) in the gut

Respiratory Fluoroquinolones

• Binds to cations (Ca2+, Mg2+) in the gut

• Warfarin (enhances anticoagulant effect)

Vancomycin

concomitant nephrotoxins

linezolid

serotonergic agents due to inhibition of monoamine oxidase (SSRIs, MAOIs, TCAs, carbamazepine)

Aminoglycosides

concomitant nephrotoxins and neuromuscular blocking agents

• Avoid in pregnancy; safe with breastfeeding

polymyxins

concomitant nephrotoxins and neuromuscular blocking agents

• Avoid in pregnancy and breastfeeding

Neuraminidase Inhibitors, baloxavir marboxil

influenza vaccine (may diminish development of immunity)

Rifamycin

strong CYP450 inducer (statins, calcium channel blockers, warfarin, tacrolimus, azoles)

Isoniazid, Pyrazinamide, Ethambutol

none