Principles of Prescribing in Renal Disease Flashcards
What is the role of the kidney?
Filter blood
Regulate blood vol + plasma osmolarity
Secrete hormones
What are the 2 types of renal impairment?
Chronic kidney disease (CKD)
Acute kidney disease (AKD)
What is CKD?
Reduction in kidney function due to structural damage present for more than 3 months
What is AKI?
Acute drop in kidney function
What are the CKD causes?
Hypertension
Diabetes
AKI
Medicines
Obstructive uropathy
Obesity
Cardiovascular disease
What is the presentation of CKD?
Usually asymptomatic
= diagnosed with routine check ups
What are the complications of CKD?
Anaemia
Renal bone disease
Cardiovascular disease
Peripheral neuropathy
Dialysis related problems
Why is anaemia a CKD complication?
Secrete erthrocreatine
= increase RBC production
BUT anaemia decreases this
Why is renal bone disease a CKD complication?
Impaired absorption of Ca2+
= cannot be used in reabsorption of bone growth
Why is cardiovascular disease a CKD complication?
Kidneys don’t work
= fluid build up
= more pressure on the heart
Why is peripheral neuropathy a CKD complication?
Imbalance of electrolytes?
How do you manage CKD?
Monitor renal function
Suspend nephrotoxic medication
Monitor complications = anaemia + RBD
What do you monitor for CKD?
eGFR
CrCl
ACR
What can get through if there is damage?
Bigger molecules such as proteins
What is the problem with eGFR?
Use standardised BSA = 1.73m2
= overestimates smaller patients
= underestimates larger patients
When do you NOT use eGFR?
Drug dose titrations
Elderly patients
Extreme of muscle mass
How many stages of CKD is there?
5
What is stage 1 of CKD?
Kidney damage with normal kidney function
What is stage 2 of CKD?
Kidney damage with mild loss of kidney function
What is stage 3a of CKD?
Mild to moderate loss of kidney function
What is stage 3b of CKD?
Moderate to severe loss of kidney function
What is stage 4 of CKD?
Severe loss of kidney function
What is stage 5 of CKD?
Kidney failure
What are the steps to management of treatment of CKD?
Identify underlying cause
Treat complications
How do you treat anaemia?
Erythropoietin = subcutaneous injection
BUT limited by supply of Fe in the body
= need Fe replacement with it
What are the different pharmacological management of CKD?
ACEi
Anti platelet
Statin
SGLT-2
When are ACEi used?
Protective in CKD
BUT in AKI remove
What are the problem with ACEi?
Increase K+ BUT a decreased kidney function also increases it
What is an example of an anti-platelet?
Aspirin
What must you do with an anti-platelet?
Monitor bleeding
What are signs for GI bleed?
Dark stool + high urea
Coffee ground vomit
What is SGLT-2?
Na-glucose-ligand transporters
Stops progression
BUT in acute = damaging
What are the NICE guidelines for AKI?
SrCr increase of > 26 micromol/L in 48hrs
Which medications can cause AKI?
DAMN
Diuretics
ACEi/ARBs
Metformin
nSAIDs
What can also cause AKI?
Contrast media (dye)
What does serum creatine estimate?
Patient’s kidney function
What is the equation for serum creatine?
SrCr
M = 1.23
F = 1.04
When do you caution using CrCl measurements?
Elderly, body builders, amputees, muscle wasting disorders + vegans
Why is CrCl more accurate?
Ideal body weight
What are the risk factors of AKI?
Diabetes
CKD
HF
Elderly = over 65
Liver problems
Medicines
Contrast media (dye)
What are the causes of pre-renal conditions?
AKI
Lack of perfusion
= pregnancy
= vomiting
= diuretic use
Loss of fluid
What are the post renal causes?
AKI
Backlog of urine
= pregnancy
= bladder obstruction
= stones
What are the intra renal causes?
AKI
Pregnancy = preeclampsia
Pregnancy unrelated = glomerular disease
How many stages of AKI is there?
3
What is stage 1 AKI?
Rise 1.5-2 fold from baseline creatine or urine output
What is stage 2 AKI?
Rise of 2-3 fold creatine or urine output
What is stage 3 AKI?
Rise >3 fold creatine or urine output
What is the management of AKI?
Underlying cause
Pre-renal = provide IVT resuscitation
Post-renal = remove obstruction
Hold nephrotoxic drugs
What is the main complication of AKI?
Hyperkalaemia
What is the normal range of K+?
3.6-5.2
Over 6 = BAD
What can hyperkalaemia result in?
Fatal cardiac arrhythmias
= ventricular fibrillation
How do you treat hyperkalaemia?
Protect the heart
IV calcium gluconate
What does IV calcium gluconate do?
Stabilises myocellular lining of the heart
= prevents arrhythmias
How do you treat hyperkalaemia?
Shift K+ into cells
IV insulin
Nebulised salbutamol
What must IV insulin be given alongside to?
Glucose
How do you treat hyperkalaemia?
Remove excess K+
PO calcium resonium
What are the other complications with AKI?
Fluid overload
Metabolic acidosis
Uraemia (results in encephalopathy)
What is uraemia?
Swelling of the brain
= NS disorders
What are signs of opioid toxicity?
Respiratory depression
Pin prick pupils
What are problems with renal drugs?
Renally excreted
Risk of accumulation
Increased drug half life
Reduce efficacy
What are the prescribing approaches?
Increase dosing interval
Decrease dose
Combo of dose reduction + increased interval
Review drug choice
Why increase dosing interval?
Gives body to excrete the drug
Why decrease the dose?
Time dependant meds
Why do a combo?
Increase more time to filter out
Why review drug choice?
Hepatic metabolism?
Inactive metabolite?
What are the conditions that DOACs can be used for renal disease?
> 80 years old
<60kg
<133micromol/L
What is an example of a DOAC?
Apixaban
When do you avoid nSAIDs when possible?
CKD
When do you remove nSAIDs?
AKI
What do nSAIDs do?
Prostaglandin synthesis inhibited
= inhibit vasodilator PGs
= effect renal perfusion
What do ACEi do in AKI?
Dilate efferent arteriole
= remove blood pressure
= decrease perfusion
What do ACEi do in CKD?
Remove pressure = good
