CPT S9 - Diuretics Flashcards
What are the physiological mechanisms the kidney is responsible for?
Regulatory
Excretory
Endocrine
Metabolism
What regulatory functions is the kidney responsible for?
Fluid balance
Acid-base balance
Electrolyte balance
What endocrine functions is the kidney responsible for?
Renin-Angiotensin-Aldosterone
Erythropoetin
Prostaglandins
What excretory mechanisms does the kidney control?
Waste product excretion
Drug elimination;
-Glomerular filtration
-Tubular secretion
What metabolic functions is the kidney responsible for?
Vitamin D
Polypeptides;
-Insulin
-PTH
What are some ADRs for Thiazides?
Gout
Erectile dysfunction
What are some ADRs for furosemide?
Ototoxicity
What are some ADRs for spironolactone?
Hyperkalaemia
Painful gynaecomastia
What are some ADRs for bumetanide?
Myalgia
Which diuretics do ACE inhibitors interact with, and what is the result of this?
K sparing diuretics
Causes increased hyperkalaemia
Leads to cardiac problems
Which diuretics does aminoglycosides interact with, and what is the result of this?
Loop diuretics
Ototoxicity
Nephrotoxicity
Which diuretics does digoxin interact with, and what is the result of this?
Thiazides and loop diuretics
Hypokalaemia
Leads to increased digoxin binding and toxicity
Which diuretics do β-blockers interact with, and what is the result of this?
Thiazide diuretics
Hyperglycaemia
Hyperlipidaemia
Hyperuricaemia
Which diuretics do steroids interact with, and what is the result of this?
Thiazides and loop diuretics
Increased risk of hypokalaemia
Which diuretics does carbamazepine interact with, and what is the result of this?
Thiazide diuretics
Increased risk of hyponatraemia
What is the recommended treatment for heart failure?
Loop diuretics Thiazide diuretics - as an add-on (Spironolactone - non-diuretic benefits) ACEi or angiotensin II antagonists β-blockers
Why does diuretic resistance occur?
Incomplete treatment of the primary disorder
Continuation of high Na intake
Patient non-compliance
Poor absorption
Volume depletion decreases filtration of diuretics
Volume depletion increases serum aldosterone, which increases Na reabsorption
NSAIDs can reduce renal blood flow
What is the recommended treatment for hypertension?
Thiazide diuretics Spironolactone (Loop diuretics) ACEi or angiotensin II antagonists β-blockers
What is the recommended treatment of decompensated liver disease?
Spironolactone (HUGE doses)
Loop diuretics
What are some potentially nephrotoxic drugs?
ACEi Aminoglycosides eg gentamicin Penicillins Cyclosporin A Metformin NSAIDs
What are some important things to remember when prescribing to CKD patients?
Avoid nephrotoxins Reduce dosages in line with GFR if metabolism or elimination via kidneys (except furosemide) Monitor renal function and drug levels Uraemic patients more likely to bleed Hyperkalaemia more likely in CKD
What are some important things to remember when prescribing to elderly patients?
Renal function often over-estimated as creatinine is body mass-dependent
Start low and titrate up cautiously
Polypharmacy more likely
What is the management of hyperkalaemia?
Identify cause
ECG!!
How is hyperkalaemia treated?
Calmcium gluconate Insulin+dextrose Calcium resonium Sodium bicarbonate Salbutamol
What are some general ADRs for diuretics?
Anaphylaxis/rash Hypovolaemia Hypotension Electrolyte disturbance Metabolic abnormalities
What are the types and causes of hypertension?
Primary/essential hypertension;
-High BP without any single evident cause
-90% hypertensive population
Secondary hypertension;
-High BP with a discrete, identifiable underlying cause
-10% hypertensive population
What is the treatment of hypertension?
Identify & treat any underlying cause
Identify & treat any CVS risk factors or co-morbidities
Lifestyle advice
Pharmacological therapy
What is the threshold BP for treatment?
> 140/90
Give some examples of lifestyle advice you might give patients with hypertension
Maintain normal BMI Reduce salt intake to 30 mins/day Eat >5 fruit/veg per day Reduce fat intake Smoking cessation Relaxation therapies
What is the 1st line treatment for hypertension?
ACEi/angiotensin receptor blockers (ARBs)
Ca channel blockers
Diuretics
Give some ACEi ADRs
Dry cough (10-15%)
Angio-oedema
Renal railure
Hyperkalaemia
Give some examples of ACEi drugs
Lisinopril
Ramipril
Give some examples of ARBs
Losartan
Valsartan
Candesartan
What are some ADRs for ARBs?
Renal failure
Hyperkalaemia
Give some examples of Ca channel blockers
Amlodipine
Diltiazem
Verapamil
What are some ADRs for amlodipine?
Sympathetic activation
Oedema
Flushing, sweating, throbbing headache
Gingival hyperplasia
What are some ADRs for verapamil?
Constipation
Bradycardia
Reduced myocardial contractility
What are some ADRs for diltiazem?
Bradycardia
Reduced myocardial contractility (not as bad as verapamil)
Give an example of a thiazide
Bendroflumathiazide
What are some ADRs for bendroflumethiazide?
Hypokalaemia Increased urea and uric acid Impaired glucose tolerance Increased cholesterol and triglyceride Activates RAAS
What are some atypical anti-hypertensive drug classes?
α-adrenoceptor blockers β-adrenoreceptor blockers Direct renin inhibitors Centrally acting agents Vasodilators
What are the properties of α-adrenoceptor blockers?
Selective antagonism at post-synaptic α-1 receptors
Reduce peripheral vascular resistance
Safe in renal disease
Eg Doxazosin
Give some ADRs for α-adrenoceptor blockers
Postural hypotension Dizziness Headache Fatigue Oedema
Give some properties of β-adrenoreceptor blockers
Reduce heart rate and cardiac output
Inhibit renin release
Initially TPR increases but returns to normal
Eg Atenolol, bisoprolol
Give some ADRs for β-adrenoreceptor blockers
Lethargy Impaired concentration Reduced exercise tolerance Bradycardia Cold hands Impaired glucose tolerance Bronchospasm Dry cough
What are the properties of direct renin inhibitors?
Low bioavailability
Mainly eliminated unchanged in faeces
Give some examples of centally acting agents
Methyldopa
Clonidine
Monoxidine
What is rebound hypertension?
Withdrawal of a centrally acting anti-hypertensive agent causes;
- Desensitisation of inhibitory α2 receptors
- Super-sensitivity of post-synaptic α1 receptors
How may heart failure develop?
Ischaemic heart disease
Hypertension
Cardiopathies
Valve disease
How is heart failure treated?
RAAS antagonism; -ACEi -ARB -Aldosterone β-blocker
