Cardiovascular Drugs
Cardiovascular Drugs
> Heart Failure
>> Aldosterone antagonists (Spironolactone) AMH done
>> Loop-diuretics (Frusemide aka Lasix) AMH done
Hypertension
> Sartans
> ACEi (peril)
> B-blockers
Antiarrythmics
> Digoxin (foxglove)
Triple whammy:
> Heart Failure
- Rx improves systolic failure (dilated cardiomyopaphy), but no improvement with diastolic failure (hypertrophic cardiomyopathy)
- Dilated: sarcomeres added in series > increased volume. Hypertrophic: sarcomeres in parallel > ↓chamber volume
>> Aldosterone antagonists (Spironolactone) AMH done
- Angiotensinogen made in liver and muscles
- Low blood volume triggers juntaglomerular cells in kidney to activate prerenin, secreting renin
- ATinogen converted by renin into ATI in circulation
- Converted by ACE in the lungs to ATII
- ATII vasoconstricts and stimulates aldosterone release from adrenal cortex
- Aldost. increases resorption of Na and Water in distal tubule
- Spironolactone inhibits this Na absorption from distal tubule > ↑H2O excretion, ↓K excretion
- Precaution hyperK
- Also has anti androgenic effect, can be used for hirsutism, acne
- Adverse effects, gynocomastia, menstral anomalies, sex dysfunction
>> Loop-diuretics (Frusemide aka Lasix) AMH done
- treats oedema through inhibition of Na/Cl resorption in accending loop of Henle
- last 4-6 hours
- Precautions: oto/nephrotoxics, low Na/K/Mg/Ca, hypotension, Less lowK if with ACEi
- Pregnancy : C
- Breastfeeding with care
- Dose: 08 or 08 + 12
- 1mg/kg daily/BD increasing by 1mg/kg/dose to 4mg/kg BD max
- Oral bioavailability = 50% i.e. IV x 2 = PO dose
- Monitor wt and electrolytes
Hypertension
> Sartans
- angiotensin II receptor antagonist
> ACEi (peril)
> B-blockers
Antiarrythmics
> Digoxin (foxglove)
- increases vagal tone / reduced sympathetic tone slowing AV conduction. Increases Ca stores increasing contractility.
Triple whammy:
- ACEi (pril) OR ATII antagonist (sartan) (dilated efferent, reduces GFR)
- Diuretic
- NSAID or COX2 inhibitor (block PG, which leads to constriction of afferent arteriole, reduces GFR)