Cardiovascular Flashcards
How does aspirin inhibit platelet aggregation?
Alter the balance between Throboxane A2 and Prostacyclin.
This is irreversible for the life of the platelet.
How does clopidogrel inhibit platelet aggregation?
Inhibits ADP induced platelet aggregation.
How does dipyridamole work on inhibiting platelet adhesion?
It inhibits phosphodiesterase (enzyme found in platelets).
Do antiplatelet drugs slow down or speed up the bleeding time during tooth extractions?
They prolong the bleeding time due to these drugs inhibiting platelet adhesion- a blood clot therefore cannot be formed.
What new antiplatelet drugs are used in conjunction with aspirin?
Prasugrel and Ticagrelor. These are only prescribed for acute coronary syndromes.
What three anticoagulant drugs are prescribed depending on the patient’s weight?
Rivaroxiban (1 daily), Apixaban (2 daily) and Dabigatran (2 daily).
How does warfarin work?
It is a coumadin based anticoagulant. Warfarin inhibits the synthesis of vitamin K dependent clotting factors. 2 7 9 and 10 (slow) and Protein C and Protein S fast).
What test is used to monitor warfarin and how does this test work?
INR test. ‘Prothrombin time’- measures the time it takes for your blood to clot. If your INR score is too high you are at an increased risk of bleeding.
What test is used to monitor warfarin and how does this test work?
INR test. ‘Prothrombin time’- measures the time it takes for your blood to clot. If your INR score is too high you are at an increased risk of bleeding. The therapeutic range is between 2 & 4.
What is haemophillia?
An inherited genetic disorder that impairs the bodies ability to create blood clots- this results in prolonged bleeding.
Give examples of drugs that you cannot take with warfarin?
Amoxicillin, metronidazole, erythromycin and NSAIDS.
What is a prodrug?
A biologically inactive compound which can be metabolised by the body to produce a drug.
Extrinsic activation - Vessel injury occurs then Factor 7 is released. This releases factor 10a which converts prothrombin into thrombin. This converts fibrinogen to fibrin.
.
Why should be avoid taking NSAIDS when taking warfarin?
NSAID will prolong action and inhibit platelets – avoid
What type of drugs are statins?
HMG coA reductase inhibitors.
What is an example of a prodrug?
Simvistatin.
What do statins do and what are the side effects of this medication? Name another medication that interacts with statins.
Inhibit cholesterol synthesis in the liver
Reduce total cholesterol and LDL- cholesterol
Side effects – possible myositis with some drug interactions – includes antifungals (fluconazole). cause plasma levels to go up drmatically and cuse myostitis.
Beta-adrenergic blockers (β-blockers)
Atenolol – selective - β1 only
Propranolol – non-selective – β1 and β2
Many others (-olol)
Stop arrhythmias leading to cardiac arrest (Ventricular fibrillation – VF)
* Reduces heart muscle excitability
b2 receptor in lungs- also present in brain for anxiety, increases risk of getting asthma etc.
B1blocks adrenaline to heart- slows hert down and to make it function less well (heart attack patients dnt want their heart to be over stretched, they want electrical exitability of heart being less0.
beta blocker for heart attack patients. Cardiac arrthymias.
What are diuretics used for and name examples of them.
Antihypertensive and heart failure.
- Loop diuretics (furosemide)
- Thiazide diuretico (bendroflumethazide).
How do diuretics work and what are the side effects of them?
Increase salt and water LOSS Reduce plasma volume Reduce cardiac workload *Side effects – can lead to Na+/K+ imbalance if not monitored carefully Can lead to dry mouth in the elderly.
How does spironolactone work?
Spironolactone is an aldosterone receptor antagonist that acts in the renal distal tubule and collecting ducts, decreasing the reabsorption of sodium and water and decreasing the excretion of potassium.
What do nitrates do?
Nitrates dilate the veins and reduce preload to the heart. They dilate resistance arteries which reduces cardiac workload and reduces cardiac oxygen. They also dilate collateral coronary artery supply to reduce anginal pain.
How do calcium channel blockers work?
They act by reducing hypertension due to blocking calcium channels in smooth muscle.
2 drugs work on peripheral blood vessels (relaxation and vasodilation):
nifedipine and amlodipine.
Some more actively work on the heart muscle itself (slow conduction of pacing impulses):
verapamil.
What is the side effect most commonly associated with nifedipine, cyclosporin and phenytoin?
Overgrowth of gingival.
What do ACE inhibitors do and name some examples of them.
Ramapril, lisinopril and enalapril.
They inhibit the conversion of angiotensin 1 to angiotensin 2.
Prevents aldosterone dependent absorption of water and salt.
What are the side effects of ACE inhibitors?
Cough and hypotension.
Ora symptoms- angio-oedema and lochenoid reaction.
Name an example of angiotensin 2 blockers.
Losartan. They act in the same way as ACE inhibitors but by a different mechanism.