drugs and the kidney dr. shahrzad shahidi drugs & the kidney
TRANSCRIPT
Drugs and The Kidney
Dr. Shahrzad Shahidi
Dr. Shahrzad Shahidi
Drugs & The Kidney
Introduction • The heart pumps approximately 25% of CO
into the kidneys• Any drug in the blood will eventually reach
the highly vascularized kidneys• May potentially cause drug-induced renal
failure• The drug may be filtered or secreted into the
lumen of the renal tubules• The concentrated drug exposes the kidney
tissue to far greater drug concentration per surface area
Clinical Presentation
• Drug-induced renal disease can mimic renal disease from other causes, such as autoimmune disease & infection
• A thorough PEx & medical Hx should be performed• Increase in serum Cr & BUN• Additional urine tests: Pr excretion, Cr concentration,
osmolality or Na excretion• A thorough & accurate review of all medications,
including all prescription, over-the-counter & herbal medications
• Importance of dose & duration of exposure• Rule out all other causes of kidney failure
Pseudo Renal Failure• ↑ BUN due to protein catabolism– Steroids, tetracyclines
• ↑ SCr due to competitive inhibition of cr secretion– Trimethoprim, Cimetidine
• Trimethoprim– 15-35% rise SCr fully expressed after 3 days–More sig in pts with pre-existing renal dysfunction– Can occur with normal doses– Completely reversible when drug is discontinued
Mechanisms of nephrotoxin-inducedARF
• Direct nephrotoxicity– Tubuloepithelial injury– ATN (e.g.,aminoglycosides)– Osmotic nephrosis (e.g., hypertonic solutions, IV IG)
• Interstitial nephritis– Acute allergic interstitial nephritis (e.g., penicillins)– Chronic interstitial nephritis (e.g., calcineurin inhibitors)– Papillary necrosis (e.g., NSAIDs)
• Glomerular disease– Glomerulonephritis (e.g., gold, penicillamine, ACE inhibitors)– Renal vasculitis (e.g., hydralazine)
• Obstructive uropathy– Crystalline nephropathy (e.g., acyclovir, indinavir)
• Indirect nephrotoxicity– Decreases intrarenal blood flow (e.g., ACE inhibitors, NSAIDs)
Patterns of Drug-induced Lesions
Tubulointerstitium
• Acute tubular injury - Osmotic
nephrosis-
Nephrocalcinosis- Crystal NP
• Acute interstitial nephritis
• Chronic tubulointer-stitial nephropathy
Glomeruli
• Minimal change disease
• Focal segmental glomerulosclerosis
• Membranous GN
• Crescentic GN
• Thrombotic micro-angiopathy
Blood vessels
• Hyalinosis
• Thrombotic micro-angiopathy
•Vasculitis
Patterns of Drug-induced Lesions
Tubulointerstitium
Acute interstitial nephritis
Chronic tubulointer- stitial nephropathy
Acute tubular injury
- Osmotic nephrosis
- Nephrocalcinosis
- Chrystal NP
Glomeruli
Minimal change disease
Focal segmental glomerulosclerosis
Membranous GN
Crescentic GN
Thrombotic micro-angiopathy
Blood vessels
Hyalinosis
Thrombotic micro-angiopathy
Vasculitis
NSAID CNINSAID
Bisphosphonates
Captopril Hydralazin
Rifampicin
CisplatinTamoxifen
Lithium
SirolimusInterferon
CNI
ACE-I
Antibiotics
DiazepamLithiumThiazids
CNI COX2-I
BarbituratesVirostatics
BisphosphonatesHES
Cisplatin
Quinolones
Clopidogrel
Quinine Phenytoin
Sulfasalazine
Ranitidin
Case PP: Female , 50 y CC: Fatigue since 1 wk agoPI: Nocturia, Polyuria 2 wksPH: Sinusitis 3 wks ago, treated with Amoxicilline
500 mg 3 tab/d for 2 wks, HTN 5 yrsFH: HTN in her mother, DM in her brotherPE: BP: 90/60, PR: 86, Pallor, dry mouth & skin.
Nocturia, Polyuria Amoxicilline Fatigue
Case • Hb: 10 g/L• FBS: 80 mg/dl• BUN: 60 mg/dl• Cr: 4 mg/dl• Na: 124 meq/L• K: 6 meq/L• UA: 9 mg/dl
• U/A: – SG 1.007– Pr +– Glu +– RBC 6-8/HPF– WBC 10-15/HPF– WBC cast 0-1/LPF
• U/C: Neg
Based on Experimental AIN
www.nature.com/ki/journal
Pre-renal causes• Vasoconstriction–Contrast agents–Amphotericin, noradrenalin,
immunosuppressive agents such as tacrolimus & cyclosporine– Iodinated contrast media, in particular, have
been shown to inhibit the synthesis of nitric oxide in renal artery smooth muscle
Ionic vs. Nonionic
High (1500-1800) Low (600-850) Iso-osmolal (~ 290 mOsm/kg))
Radiocontrast Agents
• Pathogenesis:
– Renal Vasoconstriction (Adenosine, Endothelin)
– Tubular Injury Oxidative stress induced damage
Radiocontrast Agents
• Risk Factors: – Underlying renal disease (Cr >1.5mg/dl)
– Diabetic nephropathy, HF, Hypovolemia
– Multiple Myeloma
–Dose (lower doses safer but not necessarily safe)
Radiocontrast Agents
• Incidence
– Negligible when renal function is normal (even if diabetic)
– 4 -11% in patients with Cr 1.5 – 4.0 mg/dL
– 50% if Cr > 4.0 mg/dL and in diabetic nephropathy
• Diagnosis
– Characteristic rise in plasma Cr following administration of
the agent
–
Radiocontrast Agents
Prevention: – Use of alternative diagnostic procedures in high risk patients– Avoidance of volume depletion or other nephrotoxins– Low-doses of low- or iso-somolar agent– IV saline
Radiocontrast Agents
Case • 65 year old male with H/o HTN, ventricular arrythmias
controlled on Amiodarone, OA on NSAIDs. presents with puffiness on face on waking up. Has bilateral pitting edema.
• U/A: 3+ pr, RBC 3-5/HPF, WBC 15-20/HPF • 24 h urine pr : 4 g• BUN: 80 mg/dl , Cr: 5 mg/dl , Serum Albumin : 2.8 g/dl, TSH :
Nr • The most likely Diagnosis?
A) Amiodarone induced hypothyroidismB) RPGNC) NSAIDs induced nephrotic syndrom & interstitial nephritis
• The most likely Management & Follow up?
Nephrotic syndrome
• Abnormal amounts of Pr in the urine• Drugs : NSAIDs, penicillamine & gold,…. • Damage the glomerulus & alter the ability of
the glomerulus to prevent Pr from being filtered
• Stopping the drug may resolve the damage to the glomerulus
Nonsteroidal Anti-InflammatoryDrugs (NSAIDs)
Chemical Structure Generic NameAcetic acids: Diclofenac, Indomethacin,
Sulindac,
Fenamates: Meclofenamate, Mefenamic acid
Napthylalkanones: Nabumetone
Oxicams: Meloxicam , Piroxicam
Propionic acids: Fenoprofen, Flurbiprofen, Ibuprofen, Ketoprofen, Naproxen, Oxaprozin
Pyranocaboxylic acid: Etodolac
Pyrrolizine carboxylic acid: Ketorolac
Selective COX-2 inhibitors: Celecoxib, Rofecoxib
• Hemodynamically- Induced ARF
• Acute Interstitial Nephropathy + Proteinuria
• Papillary necrosis & CRF(Analgesic nephropathy)
• Salt & water retention: Hyperkalemia, HTN
NSAIDs
NSAIDs• Acute Interstitial Nephropathy +
Proteinuria Acute interstitial nephritis Minimal-change glomerular disease Proteinuria Prognosis good after discontinuation
of therapy; Corticosteroids ?
NSAIDs• Analgesic nephropathy (Chronic Interstitial Nephritis & Papillary necrosis )
– Single vs. combined analgesics
– Dose dependent (at least 1 kg)
– Patients with history of depended behaviors
– Slowly progressive ; Asymptomatic, sometimes hematuria, flank pain, or urinary infections.
– Being responsible for 1% to 3% of ESRD cases
Analgesic Nephropathy
Papillary necrosis
Papillary necrosis
Analgesic Nephropathy
NSAIDs/COX II Inhibitors
• Physician would like to switch previous patient from Naproxen to Celecoxib
• Are Cox II inhibitors less likely to cause ARF compared to NSAIDs?
NSAIDs/COXibs• Use with caution in CKD (grade 3 or greater)• Inhibit renal vasodilatory prostaglandins E2 & I2 – Produced by COX-2
• Reversible reduction in GFR– Higher risk if intravascular volume depletion– Management: D/C drug, use alternate analgesia
• HTN– Edema, sodium and water retention– Mean increase SBP 5 mm Hg
• Hyperkalemia Risk– Blunting of PG-mediated renin release
Osmotic nephrosis
• A morphological pattern with vacuolization & swelling of the renal proximal tubular cells.
• The term refers to a nonspecific histopathologic finding rather than defining a specific entity.
• It has a broad clinical spectrum that includes AKI & CKD in rare cases.
• High doses of mannitol, soucrose-containing IVIg, contrast dye , dextrans & starches are nephrotoxic
• Mechanism: uptake of these large molecules by pinocytosis into the proximal tubule cells.
Post-renal failure• Usually results from a mechanical barrier
to moving urine from the collecting tubules into the bladder
• Mechanical obstruction :–Bladder retention (in BPH, Neurogenic
bladder)–Kidney stones–Drugs that precipitate in the kidney
(acyclovir, ganciclovir)
DRUGS OF ABUSE
• Cocaine & heroin• Cocaine use can cause renal artery
thrombosis (clotting), severe HTN & interstitial nephritis
• Long-term cocaine use can lead to CRF• Tobacco use increase the progression
rate of CKD• Long-term tobacco use also increases the
risk of kidney cancer
• Acyclovir (antiviral agent )
• Indinavir (antiretroviral agent, protease
inhibitor)
• Methotrexate (antineoplastic agent,
antimetabolite)
• Sulfonamide antibiotics
• Triamterene
Crystal-Induced ARF
Sulfonamide crystalsIndinavir sulfate urinary crystals
Gagnon et al. 1998, Ann Intern Med 128-321
Crystal-Induced ARF
Case • 52 yo male with Type 2 DM• Baseline cr 1.8 mg/dl; BP 145/90• Enalapril 10 mg daily started & 2 weeks
later: BP 135/80• Serum cr 2.2 mg/dl
Optimal Use of ACEI/ARB• Cr ↑ 1.8 to 2.2 mg/dl in 2 wks– Accept 20-30% increase in serum cr within 1-2
months of initiation • In fact, this could be an indication that the drugs are
exerting their desired actions to help preserve renal function • Check serum cr 1-2 wks after initiation, then in 2-4 wks• If > 30% change, decrease ACEI/ARB dose by 50% &
repeat Ser Cr in 4 wks (exclude hypovolemia/NSAIDs, etc)• If > 50% rise in Ser Cr – rule out RAS
• Repeat serum cr in this patient in 1-2 wks to ensure it has stabilized
Case • 82 yo female with osteoarthritis• Admitted to hospital for CAP &
dehydration• Meds: Losartan 100mg daily + Naproxen
250mg BID• Cr 3 mg/dl
Optimal Use of ACEI/ARB
• Cr on admission 3 mg/dl in patient with CAP & dehydration–Discontinue NSAID & hold ARB until
infection treated & patient is rehydrated/cr reduced
• Resume ARB & monitor serum cr
Causes of AKI after Initiation ofTherapy with ACE Inhibitor or ARB
• BP insufficient for adequate renal perfusion– Poor cardiac output– Low systemic vascular resistance (e.g., as in sepsis)– Volume depletion (GI loss, excess diuretic use, …)
• Presence of renal vascular disease*– Bilateral renal artery stenosis– Stenosis of dominant or single kidney– Afferent arteriolar narrowing (caused by HTN, cyclo..)– Diffuse atherosclerosis in smaller renal vessels
• Vasoconstrictor agents (NSAIDs, cyclosporine)
• Be aware of nephrotoxic potential of specific drugs • Identify patients at risk • Be aware of increased risk in elderly • Asses the benefit/risk ratio for Rx of potentially nephrotoxic drug•Monitor the RFT if necessary
Prevention: General Rules
• Avoid dehydration
• Limit dose & duration of treatment
• Adjust the dose based on changes in
GFR
• Avoid a combination of potentially
nephrotoxic drugs
Prevention: General Rules (Cont’d)
Conclusion• Many drugs cause AKI • Increase the risk of drug-induced AKI:– Age (particularly over 65 years)– Pre-existing renal impairment– Comorbidities such as DM, HF, liver cirrhosis– Hypovolaemia
• Addressing potential risk factors• Understanding of the mechanisms of
nephrotoxicity involved