Drugs Flashcards
How do organic nitrates work? Give two examples
Relax all types of smooth muscle
- Glyceryltrinitrate (short acting)
- Isosorbide mononitrate (long acting)
How is GTN given?
Sublingual - tablet or spray in stable angina
IV in unstable angina/MI
How is ISMN given?
Orally for prophylaxis of angina
- take in morning and at lunch in order to have ‘nitrate low period’ for rest of day to avoid tolerance
What are some side effects of nitrates?
Headaches Hypotension and fainting Reflex tachycardia (co-administer beta-blocker) Tolerance Formation of methaemoglobin (rare)
How do CCBs work?
Block Ca entry into cells, therefore reducing muscle contraction
Act on L-type Ca channels found in heart, smooth muscle and other locations
Which conditions are CCBs used in?
Hypertension
Stable angina
HR control in supra ventricular arrhythmias
Give 3 examples of CCBs and what is their selectivity for different channels?
Verapamil –> relatively selective for cardiac channels
Diltiazem –> intermediate selectivity
Amlodipine –> relatively selective for smooth muscle
Which CCBs are preferred for use in hypertension and angina, and why?
Drugs selective for smooth muscle
e.g. Amlodipine and nifedipine
To minimise unwanted cardiac effects
In which cardiac conditions should CCBs be avoided/stopped?
Heart failure
Heart block
Having which two conditions concurrently makes CCBs particularly useful?
Hypertension and angina
What are the side effects of CCBs?
hypotension
dizziness
flushing
ankle oedema
How do CCBs help in supraventricular arrhythmias? Which CCB is usually used?
Suppress conduction through the AV node
Verapamil
What is angiotensin converting enzyme (ACE) and what effects does it have?
Enzyme on surface on endothelial cells
- converts angiotensin I to angiotensin II –> vasoconstriction
- inactivates bradykinin (vasodilator)
What is the mode of action of ACE inhibitors?
Block conversion of angiotensin I to angiotensin II
What is the mode of action of angiotensin receptor blockers (ARBs)?
Block action of angiotensin II
What are some side effects of ACE inhibitors?
Initial hypotension (especially if taking diuretics) Dry cough (bradykinin in the lungs) Hyperkalaemia Angioedema Renal dysfunction
What are some side effects of ARBs?
Same as ACE inhibitors but
NO DRY COUGH
–> as no effect on bradykinin
Can ACE inhibitors or ARBs be given in pregnancy?
NO –> foetal toxicity
Can ACE inhibitors/ARBs be used in renal disease?
Should not be used in bilateral renal artery stenosis
BUT
ACE inhibitors good in diabetic nephropathy
What are the clinical uses of ACE inhibitors and ARBs?
Hypertension
Heart failure
Post MI
Give some examples of beta-blockers used in CVD and why?
Atenolol, bisoprolol
–> cardioselective (Beta-1 adrenoceptors)
Give some examples of non-selective beta-blockers and their use?
Propranolol, carvedilol
–> thyrotoxicosis, migraine
What are some side effects of beta-blockers?
Bronchospasm –> CI in severe asthma/COPD
Can worsen HR in the short term
Fatigue
Cold peripheries
Give two examples of potassium channel openers and their uses:
Nicorandil:
- used in angina refractory to other treatments
Minoxidil:
- last resort in severe hypertension but causes
reflex tachycardia (prevented by beta blocker)
salt and water retention (alleviated by diuretic)
Give two examples of alpha blockers:
Prazosin
Doxazosin
What are the clinical uses of alpha blockers?
Resistant hypertension
Symptomatic relief in BPH
Which group of patients are alpha blockers particularly useful in?
Patients with hypertension AND benign prostatic hyperplasia (BPH)
Give some examples of beta-adrenoceptor agonists
Dobutamine
Adrenaline
Noradrenaline
(catecholamines)
What are the clinical uses of adrenaline?
Cardiac arrest (IV) Anaphylactic shock (IM)
What are the clinical uses of dobutamine?
Acute but potentially reversible HF
e.g. following cardiac surgery, cardiogenic or septic shock
Name some selective and non-selective beta-blockers
Non-selective –> propranolol
Selective –> atenolol, bisoprolol, metoprolol
What are the clinical uses of beta-blockers?
Arrhythmias (reduce sympathetic drive, delay AVN conduction)
Angina (alternative to CCBs)
HF (compensated) - low dose to improve morbidity and mortality
Hypertension (no longer first line)
What are the adverse effects of beta-blockers?
Bronchospasm
Aggravation of HF (can be used low dose in compensated HF)
Bradycardia
Hypoglycaemia in patients with poorly controlled DM
Fatigue
Cold extremities
What is atropine and how does it work?
Non selective muscarinic ACh receptor antagonist
–> blocks parasympathetics so increases HR
What are the clinical uses of atropine?
Severe or symptomatic bradycardia (first line)
- glycopyrronium is an alternative
Anticholinesterase poisoning
What are the clinical uses of digoxin?
Heart failure –> increases cardiac contractility
AF –> rate control
Particularly useful in HF + AF
Which electrolyte imbalance can dangerously enhance the effects of digoxin?
Hypokalaemia
What are some of the adverse effects of digoxin?
Heart block Propensity to cause arrhythmias Nausea and vomiting Diarrhoea Disturbance of colour vision
Which AADs are used for rate control?
Class II e.g. propranolol, atenolol (beta-blockers)
Class IV e.g. verapamil, diltiazem (CCBs)
Which AADs are used for rhythm control?
Class I e.g. flecainide, propafenone, lignocaine, quinidine
Class III e.g. amiodarone, sotalol, dronedarone
Which anti-arrhythmic drugs are only used in supra ventricular arrhythmias?
Adenosine
Digoxin
Verapamil
What is the clinical use of adenosine?
To terminate paroxysmal SVT
What is the anti arrhythmic use of digoxin?
Rate control in AF
What are the anti arrhythmic uses of verapamil?
AF and atrial flutter
What is the clinical use of lignocaine?
Treatment of ventricular arrhythmias post MI
What is the clinical use of flecainide?
Prophylaxis of paroxysmal AF
What is the clinical use of amiodarone?
Pharmacological cardioversion in SVT and VT
What are the adverse effects of amiodarone?
Pulmonary fibrosis
Thyroid disorders
Photosensitivity reactions
Peripheral neuropathy
