extras

Question 1

CCB mechanisms

• rl
• non rl

Answer 1

rate limiting Verapamil
- blocks T-type calcium channels in SA/AV node to stop action potential upstroke phase 4
- blocks l-type cc in AV/SA and in myocardium to reduce contractility

Non - RL Amlodipine
- main effect in vessels blocking L-type cc to stop Ca2+ entry
- this stops vascular smooth muscle contraction and lower BP and cardiac output/inotropy

Question 2

Prodrug Strat

• enalaprilat

Answer 2

Enalaprilat active drug
- low absorption and low LogP

• Add lipophilic Ester group to make prodrug Enalapril
• body has esterase’s to break the ester down and release Enalaprilat once in systemic absorption

Question 3

Furosemide MOA

• given in HF / stroke

Answer 3

1. works in the proximal convoluted tubule
2. blocks Na/K/2Cl channel to stop ion reabsorption
3. water follows ions so it is excreted with ions, lowering blood volume, lowering BP

Question 4

Bendroflumethiazide MOA

• 3rd line HTN

Answer 4

1. works in distal convoluted tubule
2. blocks Na/Cl channel to stop ion reabsorption
3. water follows ions so it is excreted , lowering blood volume , lowering BP

Question 5

Beta Blocker MOA

Answer 5

1. blocks B1 receptor in the heart which blocks NA binding
2. this decreases SA firing to decrease the heart rate
   - it reduces cardiac output and gives LV more time to fill up to increase effectiveness of heart
3. NA binding activates adenyl cyclase which increases cAMP levels to activate PKA. PKA inc contractility so BB block this

Question 6

DVT Treatment

Question 7

Acute Stroke Care

Answer 7

1. hospitilisation + ASPIRIN 300mg stat
2. CT scan (quicker than MRI) rules out haemorrhagic stroke
3. Thrombolysis (alteplase)
   - within 4.5hrs of onset
   - 0.9mg/kg max 90mg dose
   - 10% given bolus 2-3min and 90% given over 6hrs
4. stop ALL anticoagulants, antiplatelets, NSAID’s or HTN meds because you dont want to limit blood flow

Question 8

Nitrates & Potassium Channel Activators

Answer 8

isosorbide mononitrate
- decreases coronary vasoconstriction by becoming nitric oxide in body (vasodilator)

Nicorandil at low dose is nitrate
- at high dose opens K+ channels
- opens K+ channels on smooth muscle to hyperpolarise and decrease Calcium entry

Question 9

Primary Stroke Prevention
- A-E

Answer 9

A - antiplatelet / anticoagulant
- aspirin 300mg stat on admission (avoided for 24hrs post thrombolysis)
- aspirin 300mg daily 14days then clopidogrel 75mg daily

• AF patients this antiplatelet started 10-14days after

B - Blood pressure under 130/80
- If under 55 years old –an ACE inhibitor or anangiotensin receptor blocker (ARB).
- If 55 or older or African – Caribbean origin of any age – a calcium channel blocker

C - cholesterol
- atorvastatin 40-80mg 1st line
- not used in haemorrhagic stroke

D - diabetes
- sliding scale insulin and glucose to keep tight control on blood sugar

E - Exercise
- counselling and lifestyle advice to reduce chance of stroke in future

Question 10

Sacubatril/Valsartan

• HF treatment
• used when patient displays symptoms despite treatment

Answer 10

• Neprilysin inhibitor / ARB
• Stop ACE-inhibitor minimum 36 hours
• starting dose: 49 mg/51 mg twice daily
  SBP>100, K<5.4

1. neprilysin breaks down ANP which causes vasodilation

Question 11

Beta Blocker Binding

Answer 11

1. catchecolhydroxyl binds to TM1 serine by hydrogen bonding
2. aromatic ring binds to TM6 phenyl

Question 12

Flecainide
- rhythm control

Answer 12

• sodium channel blocker
• stops sodium coming in at phase 0 prolonging refractory period

Question 13

Amiodarone
- rhythm control

Answer 13

Class III anti arrhythmic

• potassium channel blocker with some Na and Ca channel blocking effects

Works phase 0- 3 but most effect in phase 3 blocking potassium channels, prolonging refractory period