farmacologia Flashcards
açao dos diureticos ao longo do néfron
Acetazolamida é um inibidor da anidrase carbonica e age no TUBULO PROXIMAL
Furosemida bloqueia o canal NaK2Cl na porcao espessa ascendente da alça de henle
hidrochlorothiazide= inhibe o cotransportador de NaCl no tubulo distal
espironolactone =competitively inhibits the aldosterone mineralocorticoid receptor in the cortical collecting duct=inibe a abs de na no túbulo distal e a secreção de k nos túbulos coletores
Amiloride blocks ENaC (epithelial sodium channel) in the cortical collecting duct
DIURETICO EVITAR EM QUEM TEM ALERGIA A SULFA = CUIDADO COM TIAZIDICOS E DIAMOX
Drug induced AIN
Drugs associated with tubular cell toxicity and acute in- terstitial nephropathy
– NSAIDs incl Cox-2 inhibitors – Cephalosporins
– Furosemide and Bumetanide – Ciprofloxacin
– Cimetidine
– Allopurinol
aminoglycosides, amphotericin B, cisplatin, beta lactams, quinolones, rifampin, sulfonamides, vancomycin, acyclovir, and contrast agents . These agents induce renal tubular cell injury by impairing mitochondrial function and interfering with tubular transport and increasing oxidative stress and free radicals (6,10). Chronic use of acetaminophen, aspirin, di- uretics and lithium is associated with chronic interstitial nephritis leading to fibrosis and renal scarring
Rituximab
Potent anti-B-cell agent
Rapidly clears circulating B-cells
Long half life
of antibody (~ 3 weeks) of B-cell depletion
Virtually no circulating B-cells at 3 months, but with early return by 6 months
Clearance of B-cells does not correlate with clinical response
SLE
RA*
PARICALCITOL
Paricalcitol treatment reduced PTH concentrations more rapidly with fewer sustained episodes of hypercalcemia and increased Ca x P product than calcitriol therapy.
estudo VITAL Paricalcitol reduces BAP levels, which may be beneficial for reducing vascular calcification.
Paracalcitol =associacao com niveis elevados de hypercalcemia
Recommended initial dose is 0.04 to 0.1 mcg/kg (2.8 to 7 mcg) administered no more frequently than every other day at any time during dialysis. The maximum daily adult dose is 0.24 mcg/kg.
When converting a patient from calcitriol to paricalcitol, the initial dose of paricalcitol should be four times greater than the patient’s dose of calcitriol.
AINES
Prerenal azotemia
• Ischemic acute tubular necrosis
• Allergic interstitial nephritis (AIN)
• AIN plus minimal change nephropathy
• ARF plus bilateral flank pain
• Sodium and water retention
• Hyperkalemia
• CRF and papillary necrosis
Fatores de risco : idade>65 anos; DCV, DM. Homens, dose de ANE e DRC (RFGe<60 mL/min)
Dois tipos de IRA. • Hemodinamicamente mediada e a Nefrite Intersticial Aguda. • Inibição das enzimas da COX-1 com a consequente redução na síntese das PG é o efeito fisiopatológico principal na IRA hemodinamicamente mediada na com o uso de AIE
ANE na IRA • Depleção de volume do EEC • Medicações: IECA, ARA, diuréticos e inibidores da Calcineurina • Cirrose Hepática • Síndrome Nefrótica • Hipercalcemia • DRC • EAR • Idosos
NSAID associated AIN
Quadro Clínico • Aumento incidental da Cr sérica (3 a 7 dias) • Urinalise é geralmente negativa para hematúria e proteinúria. • Sedimento urinário pode apresentar : cilindros hialinos e se há NTA: cilndros epitelias ou granulares. • Cilindros leucocitários e hemáticos não são visualizados na IRA mediada hemodinamicamente
• Heterogenous picture
• Typically, no hypersensitivity reaction
• Usually middle-aged or elderly
• Majority: associated nephrotic syndrome
(MCD)
• Pyuria, hematuria, eosinophiluria (less than
methicillin-associated)
Acute Interstitial Nephritis
Drugs
ANTIBIOTICS
Penicillins, cephasporins, others (quinolones, Bactrim)
DIURETICS
Thiazides, furosemide
ANALGESICS
NSAIDS
ANTICONVULSANTS
phenytoin, carbamazepine, phenobarbitol
OTHERS
allopurinol, cimetidine
Clinical Syndromes
• Drug Induced AIN
– Variable
– Full-blown hypersensitivity reaction to
asymptomatic increase in Scr
– Nephritic / Nephrotic / AIN Urine sediment
– Fanconi’s syndrome, hyperkalemeic
hyperchloremic metabolic acidosis,
Nephrogenic DI
Diagnostic features
• Urinalysis
• Impaired concentrating ability (SG, low urine
osmolality)
• Leukocytosis – eosinophilia (10-30%) common
• Increased IgE
• Urine eosinophiluria
• Gallium – high sensitivity, low specificity
• Renal Biopsy
Eosinophiluria
>1% of white cells in urine stained
Wright’s and Hansel’s Stain
Both use eosin-methylene blue combinations
Hansel’s 4 fold more sensitive, less pH dependent
Sensitivity 67%, specificity 80%
CAUSES
•Acute Interstitial Nephritis
•UTI
pyelonephritis
prostatitis
Cystitis
•Glomerulonephritis
•Atheroembolic disease
Trimethoprim-Sulfamethoxazole
Elevated creatinine, no change in BUN, no
evidence of ARF: inhibition of tubular secretion
• Allergic interstitial nephritis with fever, rash, and
eosinophilia induced by sulfa moiety
• Hyperkalemia with salt wasting due to amiloride-
like action of trimethoprim
• Rarely, crystallization of sulfamethoxazole
metabolite and renal stone formation
Aminoglycoside Nephrotoxicity
25% incidence with “therapeutic” levels
• some correlation with cumulative dose
• non-oliguric ARF after 5-10 days
• Toxicity correlates with cationic charge
• Pathology: membrane phospholipidosis
• Prevention: once daily dosing
QUIMIOTERAPICOS
IRA INDUZIDA POR DROGAS
HIPOCALEMIANTES
Cisplatin Nephrotoxicity
ARF complicates in 1-25% of cases
• Accumulated by proximal tubules S3 segment
• Mitochondrial injury and free radical toxicity
• Non-oliguric ARF +/- Mg and K wasting
• Prevent by saline loading
• Carboplatin less nephrotoxic, more
myelotoxic
Pentamidine Nephrotoxicity
- Risk factors: hypovolemia and CRF
- 25-95% incidence of ARF after 7 to 10 days
- Several reports of ARF after nebulized drug
- Often pyuria, proteinuria, hematuria, casts
- Hypomagnesemia / Hypocalcemia, distal RTA
- Does not appear to be dose dependant
- Mechanism unknown
- Recovery usually within weeks
Foscarnet Nephrotoxicity
Risk factors: hypovolemia and CRF
• Acute renal azotemia within 7 days
• Associated polyuria and hyperphosphatemia
• ATN, interstitial fibrosis, glomerular crystals
• Dialysis in 10% of patients with ARF
• Slow recovery over weeks - months
Câncer e nefrotoxicidade
Mat e drogas qt
Mat e qt
Continuação
tma
Qt e mat
Irá pós tx de cela hematopoiéticas
Irá pós tx de cela hematopoiéticas
Ira pós tx cels hemato
Fármaco nefrotoxicidade
Anfotericina b
nephrotoxicity is manifested as
azotaemia, renal tubular acidosis, impaired renal concentrating ability and electrolyte abnormalities like hypokalaemia and sodium and magnesium wasting.
Forma lipossônica é menos nefrotóxicq .
The mechanism of nephrotoxicity involves direct cell membrane actions to increase permeability, as well as indirect effects secondary to activation of intrarenal mechanisms (tubuloglomerular feedback) and/or release of mediators (thromboxane A2). The latter effects are presumably responsible for the observed acute decreases in renal blood flow and filtration rate,
DIABETES INSIPIDUS, ATR DISTAL, HIPOCALEMIA, INCAPACIDADE DE CONCENTRAR A URINA
ANFOTERICINA B
26 - 83% of patients develop nephrotoxicity
• Increasing incidence b/o greater incidence of fungal
infections
• Chronic renal damage depends on cumulative dose of
ampho
– 44% of patients with CRF if > 4 g of ampho
– 8% with < 1 g ampho
• Azotemia usually reversible
Clinical
• Cumulative dose > 0.6 g (except BMT patients)
• Acute vasoconstriction
• Distal nephron damage
– Loss of urine concentration
– Distal RTA
– Wasting of K and Mg
• Azotemia
Pathology / Pathophysiology
• Vasoconstriction – acute reduction in RBF and GFR
• Histologic damage in distal nephron
– necrosis of tubular epithelial cells
– intracellular and intra-tubular calcium deposits
– tubular atrophy, interstitial edema, fibrosis
– Cytoplasmic vacuolization in smooth muscle cells in media of
renal arterioles
• Proximal and glomerular capillary damage
1)Vasoconstriction - DIMINUI PERFUSAO E tfg =Pre-renal azotemia
2)Distal Tubular Defects-
Acidification defects
Concentrating defects = hipokalemia,Hypomagnesemia,NDI
3) dano renal=Persistent
azotemia
(CRI)
Vasoconstrictive Effects of Amphoterecin B
Reduction in RBF and GFR
Possible Mechanisms
– Endothelin
– Tubulo-glomerular feedback
– Direct vasoconstrictor
– Role of voltage dependent calcium channels
– Role of arachidonic metabolites
Role of Liposomal Amphoterecin B
• Liposomes are small vesicles of phospholipid bilayer
• Taken up preferentially by reticulo-endothelial cells and
macrophages
• Enhanced therapeutic index (20 fold)
• Less toxic to kidneys
• Fewer side-effects
polymixin antimicrobial agents, colistin and polymyxin B Polimixina
Nephrotoxicity is related to their D-amino content and fatty acid compo- nent, which increases cellular membrane permeability and allows cation influx (41). This effect leads to tubular cell swelling and lysis with AKI development.
acyclic nucleotide phosphonates (adefovir, cidofovir, tenofovir)
enter the cell via basolateral human organic anion transporter–1(hOAT-1) and promote cellular injury primarily through disturbing mitochondrial function. Mitochondrial injury is manifested by mitochondrial enlargement, clumped cristae, and convoluted contours that impair cellular ener- getics (8,10,26,43). Tenofovir, which is employed widely to treat hepatitis B virus and HIV infection, is associated with proximal tubulopathy and AKI
Drug-Induced Cast Nephropathy
Vancomicina
Fator de risco nefrotoxicidade
Gentamicin Nephrotoxicity
• Non-oliguric renal failure
• Slow recovery of renal function
• Proximal tubule dysfunction (enzymuria, proteinuria,
aminoaciduria, glucosuria
• Hypomagnesemia
• Hypocalcemia
• Hypokalemia
Damage to proximal tubules
– dense osmiophilic lamellar structures (myeloid bodies) in lysosomes
– loss of microvilli of luminal surfaces
– tubular cell necosis
• Damage to glomerular capillary
– endothelial cell damage (diameter of fenerstrae)
- Aminoglycosides are freely filtered
- Proximal renal tubular cells concentrate aminoglycosides
- Injury evident within hours
- Tubular cells accumulate gentamicin
- Enzymuria and proteinuria follow
Enzymuria ->Lysozymuria ->Glycosuria ,Aminoaciduria,Proteinuria,Transport defects->K and Mg wasting ,Polyuria NDI ->Necrosis
Risk Factors for Aminoglycoside Nephrotoxicity
Prolonged course of treatment
• Volume depletion
• Sepsis
• Pre-existing renal disease
• Hypokalemia
• Elderly patient
• Combination therapy with cephalosporins (partic.
Cephalothin)
• Other nephrotoxins
• Gentamicin>amikacin>tobramycin
Factors which combine with Gentamicin to
enhance nephrotoxicity
- Amphoterecin
- Contrast
- Cisplatin
Tumor lysis syndrome
– 1 in 400 patients
– Majority of BMT patients with relapse not de novo
disease
– Big problem in bulky rapidly growing radio-chemo
sensitive tumors
– Uric acid, phosphate, xanthine
– Intra-tubular precipitation – obstruction
– Volume repletion, urinary alkalinization, allopurinol
Marrow infusion toxicity
Not seen with allogeneic BMT
– Consequence of cryopreservation
• -800C, DMSO (dimethyl sulfoxide)
• Potential disruption of granulocytes and RBCs
– Side-effects: N/V, headache, fever, flushing, chills,
hyper and hypotension, bradycardia, heart block, overt
hemoglobinuria, in-vivo hemolysis