Angina Flashcards
1
Q
Stable angina
Sub-lingual GTN- Mechanism of action
A
- Nitrates are converted to NO
- NO increases cGMP synthesis and reduces Intracellular Ca2+ in vascular smooth muscle= relaxation and vasodilation
- This reduces cardiac work and myocardial oxygen demand by improving perfusion to cardiac muscle
2
Q
GTN spray- Adverse effects
A
- Flushing
- Headache
- Hypotension
- Tolerance
- Don’t use overnight- increase side effects (NOT needed)
3
Q
GTN- Contraindications
A
- Severe Aortic Stenosis- cause cardiovascular collapse
- This is because the heart is unable to increase cardiac output sufficiently through the narrow valve area to maintain pressure
- Haemodynamic instability
- Hypotension
4
Q
GTN- important interactions
A
- Phosphodiesterase inhibitors (Sildenafil)
- because of the enhanced hypotensive effect
- Anti-HTN- use with caution
5
Q
GTN- Communication
A
- Explain that you are prescribing a nitrate to relieve chest pain and or breathlessness
- May develop a headache when starting but should go
- Better at preventing than terminating angina pain, take before tasks that can bring on angina
- Because of postural Hypotension- it is a good idea to advise them to sit down and rest before and 5 minutes after taking GTN spray
- Tolerance can occur- make sure there is a nitrate free period every day during a time of inactivity (overnight)
6
Q
Beta blockers
A
See atrial fibrillation
7
Q
Calcium channel blockers
Common indications
A
- All Calcium channel blockers can be used to control symptoms in people with stable angina, BB are the main alternative
- Amlodipine is used for HTN
- Diltiazem and verapamil are used to control cardiac rate in people with supraventricular arrhythmias including supraventricular tachycardia, atrial flutter and AF
8
Q
Calcium channel blockers
MOA
A
- CCB decrease Ca2+ entry into vascular and cardiac cells, reducing the intracellular calcium concentration
- This causes relaxation and vasodilation in arterial smooth muscle, lowering arterial pressure
- In the heart, CCB reduce Myocardial contractility
- Suppression cardiac conduction, particularly across the AV node, slowing ventricular rate
- Reduced cardiac rate, contractility and afterload reduce myocardial oxygen demand preventing angina
- CCB can broadly be divided into two classes. Dihydropyridines, including amlodipine and nifedipine, is relatively selective for the vasculature, whereas non-dihydropyridines are more selective for the heart. Of the non-dihydropyridines, verapamil is the most cardioselective, whereas diltiazem also has some effects on the vessels.
9
Q
CCB
Warnings
A
- Poor left ventricular function as they worsen HF
- AV nodal conduction delay in whom they may provoke complete heart block
10
Q
CCB
Interactions
A
- Non-dihydropyridine- should not be prescribed with a BB as both classes are negatively inotropic and chronotropic and together may cause HF, bradycardia and asystole
11
Q
CCB
Communication
A
- MR and SR should be swallowed whole and not crushed or chewed
-
Common side effects- ankle oedema
*
12
Q
CCB
Monitoring
A
- Treatment efficacy can be judged by regular BP monitoring for HTN, enquiry about chest pain for angina and by pulse rate from examination or ECG
- A 24-hour tape can be performed to review arrhythmias
13
Q
Nicorandil
Common indications
A
- For prevention and treatment of chest pain in people with stable angina
- First choice treatments for stable angina are BB and CCB
- These may be used if the other drugs can not be tolerated
14
Q
Nicorandil
MOA
A
- Nicorandil causes both arterial and venous vasodilation through its action as a nitrate (see nitrate) and by activating K-ATP channels
- Efflux of K through K/ATPase channels leads to hyperpolarisation of the cell membrane and subsequent inactivation of voltage-gated Ca2+ channels
- The net effect is a decrease in free intracellular calcium
- As Ca is required for smooth muscle contraction, relaxation and vasodilation occur
- The effect of this is to reduce cardiac preload and systematic and coronary vascular resistance
- This improves myocardial perfusion and decreases myocardial work as well as oxygen demand
- Clinically, this reduces the frequency and severity of angina attacks
15
Q
Nicorandil
Warnings
A
- You should not prescribe nicorandil for patients with poor:
- Poor Left ventricular function
- Hypotension
- Pulmonary oedema
