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10 Cards in this Set
- Front
- Back
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What are the 3 types of organic nitrates?
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GTN
Glyceryl trinitrate IDN Isosorbide dinitrate IMN Isosorbide mononitrate |
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How do organic nitrates help ischaemic heart disease?
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Chemically converted in vivo
- release nitric oxide Reduce myocardial O2 demand by: - dilating veins thus dec. preload - at higher doses dilate arteries thus dec. afterload. Acute and preventative treatment. |
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What are the 2 K+ channel activators?
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Nicorandil and Ivabradine
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What is the MoA of Nicorndil?
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-open K+ channels of vascular and smooth muscle cell membrane
- K+ moves out of cell – hyperpolarisation - muscle contraction is inhibited. Reduce myocardial O2 demand by: - dilation of primary arteries (dec. afterload) - some venodilation (dec. preload) |
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What is the MoA of Ivabradine?
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- blocks Na+ channels in the sinoatrial node
Reduces myocardial O2 demand by: - dec. HR |
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In heart failure what drugs are used to decrease pre load?
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Loop or Thiazide Diuretics
Aldosterone Receptor Antagonists Venodilators (Nitrates) |
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In heart failure what drugs are used to decrease after load?
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Vasodilators (Hydralazine)
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Explain the MoA of cardiac glycoside - Digoxin?
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- Inhibit Na / K ATPase in myocyte cell membrane
- inc. intracellular Ca2+ stores in myocytes, thus causing inc. Ca2+ release during stimulation and therefore inc contractility. |
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What is a sympathomimetic?Explain the MoA...
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Dobutamine
-Mainly stimulate B1 receptors (inc. contractility and rate) -some effect on B2 receptors (arterial vasodilation = dec. afterload) and A1 but effects are thought to be balanced. |
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What is a Sympathetic Amines? Explain its MoA...
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Milrinone
Cardiac myocytes - inhibits degredation of cAMP by Phosphodiesterase3 -thus inc. intracellular Ca2+ and enhance contraction. - BV – dilates v&a, dec. preload & afterload |
