Farmako Ginjal

7/28/2019 Farmako Ginjal

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THE EFFECTS OF DRUGS ON THE KIDNEY

I. RENAL HEMODYNAMIC CHANGES

1. NSAIDS - Indomethacin

- Naproxen = Naprosyn

- Mefenemic Acid

Decrease GFR

They inhibit the synthesis of prostaglandins since they are

prostaglandine syntetase inhibitors and prostaglandins are

important in maintaining vasodilation and promotion ofrenal blood flow


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2. ANGIOTENSIN CONVERTING ENZYM ( = ACE ) INHIBITORS

- Captopril

- Enalapril

Can cause renal failure

they antagonise the angiotensin II receptors at the efferent

arterioles of glomeruli and thereby decrease intraglomerular BP

resulting in lowered GFR

3. Cyclosporin A

Can cause severe tubulo intertitial injury as well as inhibition of

prostaglandin synthesis resulting in renal failure Cyclosporin A also cause increased platelet aggregation and

predisposes to thrombosis of renal blood vessels


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II. IMMUNOLOGICALLY MEDIATED DAMAGE

1. Sulphonamide

Bactrim

AllopurinolMethicillin

Ampicillin

Cause an acute allergic intertitial nephritis associated withsteven johnsons syndrome

2. Penicillamine produce a membranous glomerulonephritisresulting in the nephrotic syndrome.

3. Rifampicin can give rise to an immune complex

glomerulonephritis Methicillin can cause rapidly progressivglomerulonephritis due to formation of anti glomerular

besement membrane antibodies ( anti GBM Antibodies )


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III. DIRECT TUBULAR TOXICITY

1. Lithium Carbonate

Is toxic to the distal tubuler and causes neprogenic diabetesinsipidius

2. Amphotericin B produces tubular damage with renal impairmenttype I RTA

3. Outdated tetracyclines cause fancony is syndrome type II RTA

tetracyclines too causes a hypercatabolic state marked elevation ofblood urea in patients with renal impairment

4. Analgesics like aspirin even paracetamol in high dose and NSAIDSCause papillary necrosis of the kidneys (analgesic Nephropathy ).

5. Aminoglycosides damage predominanatly the proximal tubules

Characteristically produce non olyguric acut renal failure.


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More commonly in the eldery espacially when they are dehydrated or givendiuretics

Combination with cephaloridine

further aggrevate nephrotoxicity

The second and third generation cephalosporin do not have a synergisticneprotoxic effect with aminoglycosides

IV. BLOCKAGE OF RENAL TUBULES1. Sulphonamides, cause crystaluria because of poor solubility

especially in an acidic urine

2. Methotrexate, cause acute tubuler necrosis due to itsprecipitation in the renal tubuler

3. Methoxy flurane, cause oxaluria with intratubular precipitationof calcium oxalate crystals giving rise to renal failure

4. Triamterent, causes crystals and casts to form in tubules,giving rise to triamterenes stones.


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V. INJURY RELATED TO CHANGE IN

ELECTRICTROLYTE

1.Diuretics cause hypokalemia inducing vacuolar

degeneration of the tubules with nephrogenic diabetes

insipidus.2.Vitamin D therapy can induce hypercalsemia presdisposing

to internal calcification and tubular damage with renal

impairmenT.


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PRACTICE POINTS

1. In Any patient with renal impairment it is alwaysuseful to take drug history.

2. In Any patient with rash and renal impairment, thinkof acute allergic intertitiel nephritis. (check eosinophilsin urine).

3. Remember aminoglycosides as a very common causeof renal impairment when dealing with a patient whohas sepsis and renal failure.

4. Withdrawl of the offending agent, eg ACE inhibitor

will result improvement of renal function.5. Sometime renal biopsy may have to do.

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