Cardiology Flashcards
(39 cards)
Mechanism of action of Bisoprolol
Cardioselective beta-1-adrenoceptor antagonist.
Blocks beta-1 receptors in cardiac and renal tissue.
Inhibits sympathetic stimulation of the heart and renal vasculature.
Blockade of the sino-atrial node reduces heart rate (negative chronotropic effect) and blockade of receptors in the myocardium depresses cardiac contractility (negative inotropic effect).
Additionally, blockade of beta-1 adrenoceptors in renal tissue inhibits the release of renin, depressing the vasoconstrictive effects of the renin-angiotensin-aldosterone system.
Name 3 complications of Bisoprolol
Bradycardia Hypotension Bronchospasm Fatigue (Can affect up to 10% of patients) Cold extremities Sleep disturbances
What is the mechanism of action of Propanolol
Non-cardioselective beta-1-adrenoceptor antagonist.
Inhibits sympathetic stimulation in the heart and vascular smooth muscle.
Name 3 indications of Propanolol
Hypertension Angina Anxiety Migraine prophylaxis Post-MI prophylaxis Carvedilol or Bisoprolol may be used as part of supportive therapy for mild / moderate heart failure.
Name 3 side effects of Propanolol
Bradycardia Hypotension Bronchospasm Fatigue (Can affect up to 10% of patients) Cold extremities Sleep disturbances Loss of hypoglycaemic awareness
What are the important pharmacokinetics/pharmacodynamics with Propanolol
Caution in diabetic patients – risk of deranged carbohydrate metabolism
Avoid in patients with Asthma and COPD – risk of bronchospasm
Do not combine Beta-Blockers with rate-limiting Ca2+-Channel-Blockers (Verapamil / Diltiazem) in anti-hypertensive therapy.
Propanolol is lipid-soluble and is predominantly cleared by the liver. Avoid in liver impairment. Avoid abrupt withdrawal – risk of liver impairment.
What type of drug are propanolol, atenolol and bisoprolol
beta blockers
What type of drugs are ramipril, enalapril, perindopril and lisinopril
ACE inhibitors
How do ACE Inhibitors work?
Inhibits conversion of Angiotensin I to Angiotensin II (a more potent systemic vasoconstrictor).
This inhibits Aldosterone release from the adrenal cortex, depressing renal sodium and fluid retention, thereby decreasing blood volume.
What are the indications of ACE inhibitors?
Hypertension
Heart Failure
Nephropathy
Prevention of Cardiovascular events in high risk patients
Name 3 side effects of ACE Inhibitors
Dry cough (10% of Patients, causing cessation of treatment in 5%) Hypotension Hyperkalaemia Renal Impairment Angioedema
What type of drugs are Isosorbide Mononitrate and Glyceryl Trinitrate (GTN)
Nitrates
What is the mechanism of action of GTN?
- Converted to Nitric Oxide (NO), a potent vasodilator.
- Cardioselective, acting on coronary blood vessels, enhancing flow of blood to ischaemic areas of the myocardium.
- Reduces myocardial oxygen consumption by reducing cardiac preload and afterload.
What are nitrates used for?
- Angina
- Severe hypertension (intravenous GTN is sometimes used in this setting)
What are the side effects of nitrates?
- Headache (incidence varies greatly, between 20-82%, causing cessation of treatment in 10%)
- Postural Hypotension / Dizziness
- Tachycardia
Why is GTN given as a spray/IV and not orally?
GTN is rapidly inactivated by first pass (hepatic) metabolism and therefore cannot be digested – sublingual spray/tablet only.
It can also be given intra-venously.
What types of drugs are Verapamil and Diltiazem
Rate-limiting Calcium Channel blockers
When are calcium channel blockers used?
Supraventricular arrhythmias
Treatment of angina
Hypertension
What are the side effects of verapamil?
Constipation (up to 11.7% of patients)
Flushing / Headache / Dizziness / Hypotension (up to 2.5% of patients)
What are the side effects of Diltiazem?
- GI disturbances (up to 6% of patients)
- Bradycardia (up to 3.6% of patients)
- Peripheral oedema i.e. ankle swelling (up to 15% of patients)
- Dizziness / Headache / Hypotension (up to 4.3% of patients)
What are the important pharmacokinetics/dynamics with Calcium Channel Blockers?
Contra-indicated in heart failure and left ventricular dysfunction due to potent negative inotropy.
Avoid in bradycardia and hypotension.
Do not use with beta-blockers.
Name 3 Non Rate-limiting Calcium Channel Blockers
Amlodipine
Nifedipine
Felodipine
What is the mechanism of action of Amlodipine?
Prevent cellular entry of Ca2+ by blocking L-type calcium channels.
Myocardial and smooth muscle contractility depressed – these drugs mainly affect smooth muscle.
Dilate coronary blood vessels and reduce afterload
What is amlodipine used for?
Hypertension
Treatment of Angina
