heart failure pharmacology Flashcards
1
Q
drugs effect heart function both..
A
- directly - force of contraction/ rhythm
- indirectly - vsascualture by altering blood volume and composition
2
Q
outline the first line of therapy
A
- beta blockers in conjunction
- ACE inhibitors
- Diuretics
- MRAs (K sparring)
3
Q
outline the second line of therapy
A
- digitalis (inhibits Na/K ATTase)
- entresto (sacubitril + valsartan)
- ivabridine (funny current blocker)
4
Q
Outline the mechanism of beta-blockers
A
- metoprolol & carvedilol
- inhibit SNS innveration via blocking B1r
reduces - chronotropy
- isotropy (contractility)
- dromotropy (conduction)
- Lusitropy (relaxation)
- minimal effect on vasculature
- preservation of ATP/ reduces work load and energy requirement
5
Q
Outline the mechanism of ACE inhibitors -
A
- Benazepril & Captopril
- produce vasodilation of vasculature by inhibiting formation of ag2
- treat chronic HT
- used in conjunction with diuretics
6
Q
AT1r blockers work by? (ARBs)
A
The sartans - eprosartan & Valsartan
- bind to AT1r on vessels
- inhibits IP3 pathway involved in increasing ca levels and therefore contraction. of smooth muscle around vasculature
- stimulates Ca release from L-T/ SR
7
Q
Loop diuretics work how?
A
Bumetanide & Edecrin
- most powerful
- targets the NKCC2 channel in the loop of Henle (thick ascending limb)
- transporter absorbs 25% of Na load
- loss of na/water
- hypoK, alkalosis
- increased ca loss
8
Q
Thiazides target the?
A
- inhibit the Na/Cl symporter in DCT
- 10% of Na reabsorbed so not very effective
- increased ca absorption
9
Q
K -sparring diuretics work by?
A
- act as antagonists of the MR present on epithelial cells of the CD
- increased water loss in urine
- inhibits insertion of preformed Na channels within apical membrane and Na/K atpases + synthesis
- weak natriuresis
- prevents XS loss of K (no hypoK)
10
Q
Natriuretic peptides work via?
ANP, BNP
A
- elevating cGMP synthesis in smooth muscle of vessels leading to vasodilation
11
Q
natriuretic peptides are produced in response to?
A
- stretch
- ag2
- endothelia levels
- SNS activity
nesirtide (recombinant BNP)
12
Q
CV and renal action of NPs include?
A
- natriuresis
- diuresis
- elevated GFR /filtration fraction
- reduced circulating ag2
- reduced circulating aldosterone
- systemic VD
- arterial hypotension
- reduced venous pressure
13
Q
sacubitril works how?
A
- blocker of neprilysin
- enzyme that degrades NP
- effective when given in conjunction with ARB valsartan
14
Q
what is the benefit of funny current inhibitors ?
A
- funny current carried by hyperpol activated cyclic nucleotide gated Chanel (HCN)
- inhibition slows AP firing rate
- reduced HR and preservation of ATP in myocyte cells
15
Q
what are the 2 types of nitro dilators?
A
- those that release NO spontaneously (Na nitroprusside)
- organic nitrates that require enzymatic processes to form NO
- tolerance occurs with frequent dosing
- work via elevating cGMP levels, up regulating K channels expression , stimulation of MLCP and inhibition of IP3 pathway
- all aim to produce VD in smooth muscle
