Cardiology Flashcards
What example of a medication has the strongest diuretic effect?
Loop diuretic - Furosemide, bumetanide
- Work on the ascending limb of the loop of Henle
- Inhibit the Na+/k+/2Cl- co-transporter
- Cause dilation of capacitance veins
What is the MOA of thiazide diuretics?
Examples: bendroflumethiazide, indapamide, chlortalidone
MOA: Inhibit inhibit the Na/Cl co-transporter in the distal convoluted tubule of the nephron
What are important interactions of statins?
Metabolism of statins is reduced by cytochrome P450 inhibitors - amiodarone, diltiazem, itraconazole, macrolides and protease inhibitors
Main information about aldosterone antagonist?
Examples: spironolactone, eplerenone
Indications - chronic HF, ascites, oedema, primary hyperaldosteronism
MOA: competitively bind to the aldosterone inhibitor
This increases sodium and water excretion
Causes potassium retention
Side effects: hyperkalaemia, gynaecomastia, liver impairment (jaundice)
Warnings and interactions of spironolactone?
Warnings - severe renal impairment, hyperkalaemia, Addison’s disease
Interactions - potassium elevating drugs (ACE inhibitors, ARBs)
What type of drug is aspirin and what is its MOA?
Anti-platelet drug
MOA:
- Irreversibly inhibits COX to reduce the conversion of arachidonic acid to thromboxane
- Reduces platelet aggregation
- Reduces the risk of arterial occlusion
What are the indications of Aspirin?
- Treatment of ACS
- Ischaemic stroke
- Prophalaxis of DVT & PE in people with arterial disease
Side effects and warnings of aspirin?
Side effects:
- GI irritation
- peptic ulcers
- peptic haemorrhage
- tinnitus
Warnings:
- not to be given to children under 16yrs - Reye’s syndrome
- third trimester of pregnancy
- peptic ulcers
- gout
What is an example of an ADP-receptor antagonist and how does it work?
Clopidogrel
MOA:
- Bind irreversibly to ADP receptors (P2Y12 subtype) on the surface of platelets
- Prevents platelet aggregation
- Reduce the risk of arterial occlusion
What are the important interactions of antiplatelets?
- antiplatelet are pro dugs ( metabolised by hepatic cytochrome P450 enzymes)
They interact with any drug that inhibits cytochrome P450 enzymes:
- omeprazole
- ciprofloxacin
- erythromycin
- some antifungals
- some SSRIs
What is the MOA of statins?
- reduce serum cholesterol
- inhibit HMG CoA reductase (involved in making cholesterol)
- increase clearance of LDL from the blood
- indirectly reduced triglycerides
Side effects of statins?
- Headache
- GI disturbance
- Muscle weakness and aches
- Rhabdomyolysis (rare)
- increase in liver enzymes (ALT)
What time of the day should simvastatin be taken?
Usually taken in the evening
- has a short half life
How are statins monitored?
1) lipid profile before initiating statin
2) lipid profile after 3 months (aiming for a 40% decrease in non-HDL cholesterol)
1) Liver function tests at baseline (ALT)
2) Check again at 3 and 12 months
What is the treatment for Atrial fibrillation?
1) DOAC (apixaban, rivaroxaban)
OR
2) Warfarin - prosthetic valves, anti-phospholipid
syndrome
3) Rate control treatment:
- Beta blocker
- Rate limiting CCB (diltiazem or verapamil)
When do you initiate treatment for AF
- CHA2DS2VASc score of 2 or above
- Men with AF and a CHA2DS2VASc score of 1- consider a DOAC
What can be used to reverse the action of heparin?
Protamine
What can be used to reverse the action of warfarin
Phytomenadione (Vitamin K1)
What patient education must be given to a patient initiated on warfarin?
- Yellow Book - alert to their warfarin therapy
- Small changes in food, alcohol and other drugs can affect the therapeutic index of warfarin
- Regular blood tests are required (INR)
- Dosage might be changed depending on INR results (to reach therapeutic index)
- It takes a few days for full anticoagulation to start (might be started with heparin)
What food and drink affect warfarin?
Food:
- Vitamin K rich food - fermented soybeans, broccoli, spinach, cabbage
Drink:
- Increased alcohol consumption (binge drinking)
What drugs interact with warfarin and increase risk of bleeding?
1) Most antibiotics
2) Antifungals
3) Antidepressants
4) Antiplatelet
5) NSAIDS
6) Analgesia - tramadol, paracetamol
What drugs interact with warfarin and increase risk of coagulation?
1) Rifampicin
2) St Johns wort
What is the MOA of warfarin?
- Inhibits vitamin K epoxied reductase
- Inhibits hepatic production of vitamin K dependent coagulation factors (factors II, VII, IX and X)
What drug increases the risk of statin-induced rhabdomyolysis?
Amiodarone
