Antibiotics Elimination Routes/CSF Penetration

Question 1

PCNs

Answer 1

Kidney -> Renal Adjustments
- EXCEPT Naf, Oxacillin (liver), and piper(dual)
- CSF penetration ONLY with inflamed meninges, high/max doses of parenteral PCNs

Question 2

Tetracyclines

Answer 2

• Tetra: kidney (renal adjustment needed)
• Doxy/Mino: nonrenal excretion (no adjust)
• Analogs: no renal adjustment, but Tige&Erava need dosage adjustment in pts w/ severe hepatic impairment (Child Pugh C)
• Not removed during HD
• MINIMAL CSF penetration

Question 3

Cephalosporins

Answer 3

Most by Kidney (renal adjustments needed)
- EXCEPT Ceftriaxone and cefoperazone (liver)
- Only Ceftriaxone not removed during HD
- ONLY parenteral: Cefuroxime, 3rd, 4th Gen reach CSF (Ceftiaxone, Ceftazidime, Cefepime)

Question 4

Metronidazole

Answer 4

• Metabolized by the liver
• Dose adjustments needed with RENAL and HEPATIC dysfxn
• Penetrates CSF and Brain Tissue (IV and PO)

Question 5

Carbapenems

Answer 5

Eliminated by kidneys -> renal dose adjustments needed
- Meropenem penetrates CSF better than Imipenem and Ertapenem

Question 6

Linezolid/Tedizolid

Answer 6

Eliminated by both renal and non-renal (no adjustments needed)
- 30% of [Linezolid] achieved in CSF

Question 7

Clindamycin

Answer 7

• Metabolized by Liver (ENTEROHEPATIC circulation causes C.diff)
• NO CSF penetration

Question 8

Aminoglycosides

Answer 8

Eliminated by Kidneys (renal dosage adjustments needed)
- Poor CSF Penetration

Question 9

Macrolides

Answer 9

Clarithro: renal (dose adjust if CrCl <30)
- E (liver) and A (biliary)
- NONE removed during HD

Question 10

TMP-SMX

Answer 10

Eliminated by kidney and liver (dosage adjustment needed if CrCl < 30ml/min)
- penetrates CNS (but not used for that)

Question 11

Polymyxins

Answer 11

• Polymyxin B and Colistin -> nonrenal, no adjustments
• CMS (prodrug)-> excreted by kidneys, dose adjustment needed when CrCl <80
• Poor CSF penetration

Question 12

Vancomycin

Answer 12

Eliminated renally (renal adjustments needed)
- Poor CSF penetration

Question 13

Synercid

Answer 13

Eliminated hepatically (liver) (hepatic adjustment in insufficiency)
- MINIMAL CSF penetration

Question 14

Tela, Dalba, Oritavancin

Answer 14

• Tela (kidney) -> renal dose adjustment
• Dalba -> dose adjustment if severe renal insufficiency and not getting HD
• Orita -> NO dose adjustments

Question 15

FQs

Answer 15

• Renal-> Levo
• Hepatic-> Moxi
• Renal/Hepatic-> Cipro, Dela
• Renal Adjustments: L.C, and D
• NONE removed during HD
• MINIMAL CSF penetration

Question 16

Monobactam (aztreonam)

Answer 16

Eliminated by Kidney –> Renal dose adjustments needed
- penetrates CSF, esp with inflamed meninges

Question 17

Daptomycin

Answer 17

Eliminated renally (dose adjustments needed for renal dysfxn)
- NO CSF penetration