W13 Kidneys + Drug Therapy Flashcards
what is a nephrotoxic drug
drugs that have the potential to harm the kidneys
what is important if a drug is classed as being nephrotoxic
understand the pharmacokinetics and pharmacodynamics of the prescribed medications
understand the clinical context of the patient and have the ability to interpret the available literature
what options do we have when reviewing medications for Acute kidney injury or Chronic kidney disease
Stop drug
withhold drug
amend dose
continue
what questions should we ask to ourselves if a patient has reduced renal function
is the patient in AKI or CKD
is the patient at risk of AKI
which medication should be suspended
which medication should be used with caution
are there any alternative option
what does should a medicine be reduced to
what additional monitoring do we need to do
what are the pharmacokinetics of the drug
what are the pharmacodynamics of the drug
what issues with absorption (A) can a patient with reduced renal function have
patients typically have oedema as their kidneys are less efficient at removing water and salt. this can affect the wall of the bowel leading to reduced absorption of drugs
what issues with distribution (D) can a patient with reduced renal function have
drug distribution is affected by water balance as oedema can affect drugs that are more hydrophillic.
Nephrotic syndrome leads to decreased protein levels in the blood. Many drugs are bound to proteins when in the blood. Lack of proteins will mean higher levels of free drug in blood. leading to toxicity
what issues with metabolism (M) can a patient with reduced renal function have
Kidney failure means that these drugs will no longer be metabolised by the kidneys
uraemia can also reduce liver function leading to decreased metabolism of drugs
what issues with excretion (E) can a patient with reduced renal function have
Reduced renal clearance means increased levels of drugs or their metabolites in the blood
What does the acronym canada stand for
Contrast media Ace Inhibitors NSAIDs Diuretics ARBs
what does NSAIDs stand for
Non-steroidal anti-inflammatory drugs
what are ace inhibitors used to treat
hypertension, heart failure, nephropathy
what do ace inhibitors work on
Renin angiotensin aldersterone system as it inhibits the conversion of angiotensin 1 to angiotensin 2
what do we do with ace inhibitors when a patient has renal failure
hold
what do we do with NSAIDs when a patient has renal failure
hold
what do selective cox 2 inhibitors do
they inhibit prostaglandins which inhbits vasodilation of afferent arteriole leading to reduced kidney perfusion
they also promote sodium retention and therefor fluid retention
what do diuretics cause
diuresis
what is the purpose of taking a diuretic
increase NaCl exretion and hence water exretion
what are the 5 different classes of diuretics (PLATO)
Potassium sparing diuretics
Loop diuretics
Aldosterone antagonists
Thiazide or thiazide like diuretics
Osmotic Diuretics
what is the most powerful diuretic
loop
what can loop diuretics be indicated for
Acute pulmonary oedema
Congestive heart failure
Fluid overload in renal/liver disease
Hypertension
when should loop diuretics be given
they should not be offered in renal impairment unless managining oedema or when renal function is recovering or patient is awaiting renal replacement therapy
what do loop diuretics act on
ascending limb of the loop of Henle
how do loop diuretics work
they inhibit Na+ reabsorption meaning less water uptake and increased urine production
they also inhibit K+ and CL- reabsorption
they also inhibit urate excretion
what are the adverse effects of a loop diuretics
Cause water excretion leading to dehydration which could lead to hypotension
Inhibit Na reabsorption = hyponatraemia
Inhibit K reabsorption = hypokalaemia
Inhibit Ca2+ reabsorption = hypocalcaemia
Inhibit Mg2+ re-absorption = hypomagnesia
Inhibit urate excretion can lead to hout
what do thiazide and thiazide like diuretics act on
distal convoluted tubule of the nephron
what is a thiazide like diuretic indicated for
oedema of cardiac renal or hepatic origin
hypertension: monotherapy or as an adjunct
what do thiazide like diuretic do
Inhibit Na+ reabsorption = increases water excretion
Inhibit Cl- reabsorption
Inhibit K+ and Mg re-absorption
Increase Ca2+ absorption into the body
what are adverse effects of thiazide like diuretics
hypokalaemia, hyponatraemia, hyperuricaemia hypercalcaemia, hyperglycaemia vasodilation (could be used as a positive)
what do aldosterone antagonists do
increases water and sodium re absorption in the collecting tubule
inhibitng alodsterone means that less water and Na will be reabsorbed but increases reabsorption of K+ so known as potassium sparing
what are other problem drugs
analgesics antibioitcs antieplieptics anticholinergics antispasmodics antihypertensives digoxin hypoglycaemic agnets Lipid lowering agents
what is a sick day rule
temporarily discontinue taking certain drugs during acute interuccrent illnesses.
