Cardiovascular System Flashcards
Name two thiazide/thiazide-like diuretics
Bendroflumethiazide
Indapamide
What is the mechanism of action of thiazide diuretics?
Inhibit Na+/Cl- cotransporter in DCT
What are some ADRs of thiazides?
- Loss of Na+ and water
- Hypokalaemic metabolic alkalosis (loss of H+ via Na+- H+ transporter (Na+ reabsorbed later on due to high conc ) and more K+ loss later in tubule due to more Na+)
- Increased Ca2+ reabsorption (hypercalcaemia)
- Gout
- Erectile dysfunction
HyperGLUC
Name two loop diuretics.
Bumetanide and Furosemide
What is the mechanism of action of loop diuretics?
Inhibit Na+/K+/2Cl- cotransporter in loop of Henle
What are some ADRs of loop diuretics?
- Loss of Na+ and water - hyponatraemia
- Hypokalaemic metabolic alkalosis (increased loss of H+ and increased loss of K+ later on, due to more Na+ in tubule)
- Increased Ca2+ loss (loss of positive luminal membrane as less K+ transported back into tubule via ROMK, so no driving force for divalent cation reabsorption)
What is an example of a potassium sparing diuretic?
Amiloride
What is the mechanism of action of amiloride?
Block ENaC at luminal surface of renal tubule
What are some ADRs specific to furosemide?
- Ototoxicity
- Gout
- Alkalosis
- Raised LDL and TG
What is an ADR specific to bumetanide?
Myalgia
What is an example of an aldosterone antagonist?
Spironolactone
What is the mechanism of spironolactone?
Competes with aldosterone at mineralocorticoid receptor in DCT/CD
(normally aldosterone upregulates ENaC channels)
What are common indications for diuretics and which classes are used?
- Hypertension - thiazides, spironolactone
- HF - loop, spironolactone
- Decompensated liver disease - spironolactone, loop
- Nephrotic syndrome - Loop, thiazides, amiloride
- CKD - loop
What are the concerns of using ACEi and K+ sparing diuretics together?
Increased hyperkalaemia risk - cardiac problems
What are the concerns of using aminoglycosides and loop diuretics together?
- ototoxicity
* nephrotoxicity
What are the concerns of using digoxin and thiazide/loop diuretics together?
- Hypokalaemia
What are the concerns of using beta blockers and thiazides together?
- Hyperglycaemia
- Hyperlipidaemia
- Hyperuricaemia
What are the concerns of using steroids and thiazide/loop diuretics together?
Hypokalaemia risk increased
What are the concerns of using lithium and thiazide/loop diuretics together?
- Lithium toxicity (thiazides)
* Reduced lithium levels (loop)
What are the concerns of using carbamezepine and thiazides together?
Increased risk of hyponatraemia
What is an example of a class IB anti-arrhythmic?
Lidocaine
What is an example of a class IC anti-arrhythmic?
Flecainide
When is flecainide indicated?
- Supraventricular tachycardia
- Ventricular arrhythmia
- WPW syndrome
What are the ADRs of flecainide?
- Pro-arryhthmic
- Flecainide flutter - increased ventricular response
- GI and CNS effects
What is the effect of flecainide?
Decreased phase 0
Give two examples of beta-blockers used as anti-arrhythmics.
Bisoprolol and metoprolol
What are the effects of bisoprolol and metoprolol on the heart? and on the ECG?
Increased APD and refractory period in the AVN
Decreased phase 4 depolarisation
Increased PR and decreased HR
What are the uses for bisoprolol and metoprolol?
Treat sinus and catecholamine dependent tachycardias
Cardioconvert reentrant arrhythmias at AVN
Protect ventricles in atrial flutter/fibrillation or flecainide flutter
What are some ADRs of bisoprolol and metoprolol?
- Bronchospasm
* Hypotension
What are two examples of class III anti-arrhythmics?
Amiodarone and sotalol
What are some ADRs of amiodarone?
- pulmonary fibrosis
- hepatic injury
- increased LDL cholesterol
- thyroid disease
- photosensitivity
- optic neuritis
What are the cardiac effects of amiodarone?
Increased ADP and refractory period Decreased phase 0 and conduction Increased threshold Decreased phase 4 Decreased AVN conduction
varying class effects
What are the effects of amiodarone on an ECG?
Increased PR, QT and QRS
Decreased HR
What are the uses for sotalol?
Wide spectrum: supraventricular tachycardias and ventricular tachycardias
What are the cardiac effects of sotalol?
Increased ADP and refractory period in atrial and ventricular tissue
Slowed phase 4 (beta blocker part of it)
Slowed AVN conduction
Which drugs are good for AF?
Rate and rhythm control
Rate: Bisoprolol/verapamil/diltiazem +/- digoxin
Rhythm: Sotalol/Flecainide + bisoprolol/amiodarone
Which drug do you give via IV for VT?
Metoprolol/lidocaine/amiodarone
Should flecainide be used alone in atrial flutter?
No - give with a AVN blocking drug to reduce ventricular rates in atrial flutter e.g. bisoprolol