Clinical pharmacology in renal disease Flashcards
Renal disease can cause drugs or their metabolites to accumulate in the body. When is this not particularly hamrful
When the drug has a high therapeutic index or low toxicity
When the metabolites have a low toxicity
Outcomes of gentamicin, lithium and digoxin toxicity
Gentamicin - Renal or Ototoxicity
Lithium - Renal toxicity, Death
Digoxin - Arrhythmias, Nausea, Death
3 methods of renal excretion
Glomerular filtration (main one)
Passive tubular reabsorption
Active tubular secretion
Where are all drugs and their metabolites filtered
The glomerulus
What should be done with a patient with reduced GFR when prescribing drugs
REDUCE DOSAGE
Increase dosage interval
Monitor blood levels for toxic drugs
4 toxic drugs
Gentamicin
Vancomycin
Digoxin
Lithium
What effect does renal disease have on the blood brain barrier
Makes it more permeable 》brain becomes more sensitive to sedatives, opiates and tranquillisers
What can renal disease do to circulating volume and what caution should be taken
Can reduce circulating volume
Making patients very sensitive to antihypertensives (ACE-I or alpha-blockers)
What can renal disease do in regards to bleeding and what cautions should be taken
Increase bleeding risk
Beware warfarin and NSAID’s
How can renal disease alter pharmacokinetics
Increased half life
Build up of drug or metabolites
Decreased protein binding 》more free drug
How can renal disease alter pharmacodynamics
Increased sensitivity to pharmacological action
Increased sensitivity to toxicity
Increased sensitivity to adverse drug reactions ADR’s
What does TDM stand for
Therapeutic drug monitoring (test?)
What should be considered when prescribing a drug to patient with renal impairment
Risk/benefit ratio
Severity of toxicity and SE
The availability of TDM
Can a different drug be used
What drugs are ideal for patients with renal impairment
Drugs with a High therapeutic index
Drugs that are metabolised by the liver and have non-toxic metabolites
Treatment for hypertension for those with renal impairment
What’s the problem with this treatment
ACE-I
Can be nephrotoxic
Four major symptoms of Drug
Induced Renal Disease
Acute renal failure
Nephrotic syndrome
Renal tubular dysfunction with potassium wasting
Chronic renal failure
3 types of acute renal failure
Pre-renal
Renal or Intrinsic
Post-renal or Obstructive
What is nephrotic syndrome and give two drugs implicated in it
It’s glomerular dysfunction and marked by HEAVY proteinuria
NSAID’S and Interferon
Why can NSAID’s cause renal failure
Decrease synthesis of renal dilators prostaglandins 》Reducing renal blood flow
What happens to urea and creatinine in drug induced renal disease
Increase
What happens to fluid and electrolytes in drug Induced renal disease
Fluid and electrolyte abnormalities
When should you really avoid nephrotoxic drugs
Patients with renal impairment
Patients that are volume deficient or hypotensive
Patients already receiving nephrotoxic therapy
