CHAPTER 2 – CARDIOVASCULAR SYSTEM
2.1 POSITIVE INOTROPIC DRUGS
2.1.1 Cardiac Glycosides
Increase the force of myocardial contraction and reduce conductivity within the AV Node
Digoxin (most commonly used)
o Pulse rate should not fall below 60bpm
o Long T½, therefore OD dosing
o Hypokalemia can make pt more susceptible to digitalis toxicity
o Liquid and tablets do not have the same bioavailability
2.2 DIURETICS
Thiazides: Used for oedema due to chronic heart failure and BP
Loop Diuretics: Used for oedema due to left ventricular failure and CHD
2.2.1 Thiazides and Related Diuretics
Inhibit sodium reabsorption at beginning of distal convoluted tubule
Act within 1-2 hours or admin and have a duration of action of 12-24 hours
Usually dose taken OM so that diuresis does not interfere with sleep
CAUTIONS: can exacerbate gout, diabetes and systemic lupus erythematosus
Can cause HYPOKALEMIA
Thiazides:
o Bendroflumethiazide
2.5mg OM – max dose for HTN
er dose used for oedema
o Chlortalidone
Longer duration of action than thiazides give ALT days to control oedema
o Other thiazides do not offer significant advantage over the above 2
Related Diuretics:
o Metolazone
Most effective when combined with a loop
Profound diuresis can occur so pt should be monitored
o Indapamide and Xipamide
Chemically related to Chlortalidone – claimed to lower BP with less metabolic disturbance,
particularly less aggravation in diabetes
2.2.2 Loop Diuretics (Work on Ascending Loop of Henle)
Used in pulmonary oedema due to left ventricular failure; IV admin produces relief of breathlessness and s
preload sooner
Resistant HTN
Furosemide and Bumetanide both act within 1 hour and have a duration of action of 6 hours, so can be given
BD
o Both drugs can cause deafness and Bumetanide can cause myalgia
o Deafness can occur when Furosemide is infused too quickly should not exceed 4mg/min
Torasemide has similar props to the above and is indicated for oedema and HTN
, 2.2.3 Potassium Sparing Diuretics And Aldosterone Antagonists
Amiloride and Triamterene – when given alone are weak diuretics so are therefore given with loops or
thiazides
K supplements should not be given with K+ sparing diuretics
Admin of K+ sparing & ACE-I/AT-II Antagonist SEVERE HYPERKALEMIA
Aldosterone antagonists (Spironolactone)
o K Sparing potentiates loops and thiazides
2.3 ANTI-ARRHYTHMIC DRUGS
2.3.2 Drugs For Arrhythmias
Supraventricular Arrythmias
o Adenosine
o Cardiac glycoside with AF
o IV ß-Blocker can achieve RAPID response
Supraventricular And Ventricular Arrhythmias
o Amiodarone
Long T½ - OD dosing
Loading dose: 200mg TDs 7 days, then 200mg BD 7 days, then 200mg OD thereafter
SIDE EFFECTS: Microdeposits on cornea, Phototoxicity, Hyperthyroidism and
Hypothyroidism, Pneumonitis, Hepatotoxicity
o Other drugs include:
ß-Blocker, Disopyramide, Flecanide, Procainamide, Propafenone, Cardiac Glycosides,
Verapamil, Adenosine, Lidocaine
Ventricular Arrhythmias
o Lidocaine – usually used in emergency situations
o Moracizine
2.4 BETA-ADRENOCEPTOR BLOCKING DRUGS
Generally all EQUALLY effective
Less bradycardia and less S/E of cold extremities: Oxprenolol, Pindolol, Acebutolol, Celoprolol
Most water soluble: Celiprolol, Atenolol, Nadolol and Sotalol – less likely to cause sleep disturbs
Cardioselective ß-Blockers: Bisoprolol, Atenolol, Nebivolol, Metoprolol and to a lesser extent Acebutolol
SIDE EFFECTS: Fatigue, coldness of extremities, sleep disturbances with nightmares
ß-Blockers can mask hypoglycaemia in diabetics
Bisoprolol and Carvedilol: only 2 x ß-Blockers licensed for Heart Failure
SOTALOL: should only be used to treat ventricular arrhythmias or supraventricular arrhythmias
CONTRAINDICATIONS: uncontrolled HF, Asthma, 2nd/3rd degree AV Block
CSM: Bhroncospasm - ß-Blockers should not be given to patients with asthma or a history of
bhronchospasm, but where there is no alternative, a cardioselective one can be given under specialist
supervision
COUNSELLING: DO NOT STOP TAKING ABRUPTLY WITHOUT ADVICE OF YOUR DOCTOR
2.1 POSITIVE INOTROPIC DRUGS
2.1.1 Cardiac Glycosides
Increase the force of myocardial contraction and reduce conductivity within the AV Node
Digoxin (most commonly used)
o Pulse rate should not fall below 60bpm
o Long T½, therefore OD dosing
o Hypokalemia can make pt more susceptible to digitalis toxicity
o Liquid and tablets do not have the same bioavailability
2.2 DIURETICS
Thiazides: Used for oedema due to chronic heart failure and BP
Loop Diuretics: Used for oedema due to left ventricular failure and CHD
2.2.1 Thiazides and Related Diuretics
Inhibit sodium reabsorption at beginning of distal convoluted tubule
Act within 1-2 hours or admin and have a duration of action of 12-24 hours
Usually dose taken OM so that diuresis does not interfere with sleep
CAUTIONS: can exacerbate gout, diabetes and systemic lupus erythematosus
Can cause HYPOKALEMIA
Thiazides:
o Bendroflumethiazide
2.5mg OM – max dose for HTN
er dose used for oedema
o Chlortalidone
Longer duration of action than thiazides give ALT days to control oedema
o Other thiazides do not offer significant advantage over the above 2
Related Diuretics:
o Metolazone
Most effective when combined with a loop
Profound diuresis can occur so pt should be monitored
o Indapamide and Xipamide
Chemically related to Chlortalidone – claimed to lower BP with less metabolic disturbance,
particularly less aggravation in diabetes
2.2.2 Loop Diuretics (Work on Ascending Loop of Henle)
Used in pulmonary oedema due to left ventricular failure; IV admin produces relief of breathlessness and s
preload sooner
Resistant HTN
Furosemide and Bumetanide both act within 1 hour and have a duration of action of 6 hours, so can be given
BD
o Both drugs can cause deafness and Bumetanide can cause myalgia
o Deafness can occur when Furosemide is infused too quickly should not exceed 4mg/min
Torasemide has similar props to the above and is indicated for oedema and HTN
, 2.2.3 Potassium Sparing Diuretics And Aldosterone Antagonists
Amiloride and Triamterene – when given alone are weak diuretics so are therefore given with loops or
thiazides
K supplements should not be given with K+ sparing diuretics
Admin of K+ sparing & ACE-I/AT-II Antagonist SEVERE HYPERKALEMIA
Aldosterone antagonists (Spironolactone)
o K Sparing potentiates loops and thiazides
2.3 ANTI-ARRHYTHMIC DRUGS
2.3.2 Drugs For Arrhythmias
Supraventricular Arrythmias
o Adenosine
o Cardiac glycoside with AF
o IV ß-Blocker can achieve RAPID response
Supraventricular And Ventricular Arrhythmias
o Amiodarone
Long T½ - OD dosing
Loading dose: 200mg TDs 7 days, then 200mg BD 7 days, then 200mg OD thereafter
SIDE EFFECTS: Microdeposits on cornea, Phototoxicity, Hyperthyroidism and
Hypothyroidism, Pneumonitis, Hepatotoxicity
o Other drugs include:
ß-Blocker, Disopyramide, Flecanide, Procainamide, Propafenone, Cardiac Glycosides,
Verapamil, Adenosine, Lidocaine
Ventricular Arrhythmias
o Lidocaine – usually used in emergency situations
o Moracizine
2.4 BETA-ADRENOCEPTOR BLOCKING DRUGS
Generally all EQUALLY effective
Less bradycardia and less S/E of cold extremities: Oxprenolol, Pindolol, Acebutolol, Celoprolol
Most water soluble: Celiprolol, Atenolol, Nadolol and Sotalol – less likely to cause sleep disturbs
Cardioselective ß-Blockers: Bisoprolol, Atenolol, Nebivolol, Metoprolol and to a lesser extent Acebutolol
SIDE EFFECTS: Fatigue, coldness of extremities, sleep disturbances with nightmares
ß-Blockers can mask hypoglycaemia in diabetics
Bisoprolol and Carvedilol: only 2 x ß-Blockers licensed for Heart Failure
SOTALOL: should only be used to treat ventricular arrhythmias or supraventricular arrhythmias
CONTRAINDICATIONS: uncontrolled HF, Asthma, 2nd/3rd degree AV Block
CSM: Bhroncospasm - ß-Blockers should not be given to patients with asthma or a history of
bhronchospasm, but where there is no alternative, a cardioselective one can be given under specialist
supervision
COUNSELLING: DO NOT STOP TAKING ABRUPTLY WITHOUT ADVICE OF YOUR DOCTOR
