Muriel Lily drug induced nephrotoxicity

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Prelude to my talk..

Transcript of Muriel Lily drug induced nephrotoxicity

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Prelude to my talk..

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Nephrotoxic Drugs

By Muriel Lily, PGY1

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• Age > 60• DM• CHF, cirrhosis• Sepsis• GFR < 60• Volume depleted• Already on a nephrotoxin

At-risk population

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Approach to the at-risk patient• Before prescribing:– Use nonnephrotoxic drugs if possible– Avoid multiple– Reduce risk factors– Adequate hydration before and during therapy– baseline renal fxn dosage adjust

• When starting nephrotoxin:– monitor renal fxn & vitals*Creatinine elevated from baseline by 44mmol/L(0.5mg/dL) or

>133mmol/L (1.5mg/dL) = ARF

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Antibiotics• Penicillins, Cephalosporins, Fluoroquinolones– Fever, rash, progressive RF, eosinophilia,

prolonged therapy “Allergy”– Renal Biopsy– Rx: • Stop drug• Steroids

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Antibiotics (cont)• Aminoglycosides– Trough >2mg/L, repeated course in months

nonoliguric ATN– Recommendations:

• hi OD dose (5-7mg/kg/24h x 2-3wks) is less nephrotoxic and equally effective

• Follow levels, correct K• CrCl > 60, 1-2.5mg/kg Q8H• CrCl 40-60, Q12H• CrCl 20-40, Q24H• CrCl <20, loading dose then monitor levels

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NSAIDs & COX 2 Inhibitors

• Edema, HTN, CHF, acute on chronic RF, dialysis

• Dose dependent• Recommendations:– Lowest possible dose– Shortest time possible– Tramadol– Colchicine/ Joint injection/ PO steroids

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Tylenol: Analgesic Nephropathy

• Analgesic abuse, chronic pain hx• Underlying chronic nephropathies (DM etc)• Investigations:– Renal u/s: small kidneys– Urine: Sterile pyuria– CBC: anemia

• Tramadol

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ACE Inhibitors & ARBs• Uremia, hyperK, dialysis dependence• Cr > 300 umol/L consult nephrology!• Avoid in bilat renal artery stenosis• ARB causes less renal failure than ACE Inhibitor

• Strategy: – In 1/52: BP, K, Cr– “diuretic holiday” x days before start– start captopril 1st, then long-acting– Ramipril: CrCl < 40, give 25% of normal dose– Losartan: avoid if GFR < 30

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Sulfa Drugs

• Crystals• Acute oliguric renal failure• Commonly: Septra, Furosemide, HCTZ, MTX• Recommendations: – Septra DS: CrCl 15-30, 50% of normal dose– Lasix: max 1-3g/d to initiate desired response– HCTZ: CrCl <10, avoid– Level 1 evidence: Trimethoprim alone is as effective

as Septra

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IV Contrast• Vasospasm & ARF• Risk factors: DM, myeloma, CRF, dehydration, diuretics, CHF• Prophylaxis:– Hold NSAIDs & diuretics, 24h pre & post contrast– IV NS pre & post contrast– 2 x 600mg PO Acetylcysteine– Low dose, low-osmolar contrast– Avoid multiple procedures in 48h– Monitor renal fxn for 48h

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When to refer to Nephrology

• Unclear cause after work-up• need for biopsy• stage 3 or 4 CKD• rapid progression of CKD

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Other Nephrotoxins

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Take Home Message• Caught early, it’s reversible• Identify at-risk patients• Baseline renal fxn using MDRD or Cockcroft-

Gault GFR• Serum drug q2-3x/wk• Serum Cr weekly to yearly• Creatinine elevated from baseline by

44mmol/L (0.5mg/dL) or >133mmol/L (1.5mg/dL) = ARF

STOP DRUG! Consult Nephrology?

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References• Naughton, C. Drug-induced Nephrotoxicity. AFP. 2008 Sept 15: 743-750.• Guo, X. How to prevent, recognize, and treat drug-induced nephrotoxicity. Cleveland Clinic

Journal of Medicine April 2002 vol. 69 4 289-290• Barclay, L. Recommendations Issued for Drug-Induced Nephrotoxicity. MedscapeCME. 2008.

Sept 30.• www.fpnotebook.com• Hewlett, T. Nephrotoxic drugs. CFP. May 2004