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10 Cards in this Set
- Front
- Back
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short acting nitrates (3)
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1. amyl nitrite (inhalant)
2. nitroglycerin (sublingual 3. isosorbide dinitrate (sublingual) **all minutes |
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long acting nitrates (2)
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1. nitroglycerin (oral, ointment, sublingual, transdermal)
2. isosorbide dinitrate (oral and chewable) |
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Nitrates mechanism of action for vasodilation
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nitrite ion --> metab to NO --> activates GC --> increases cGMP --> relaxes vascular smooth muscle
**all VSM are relaxed, but VD is uneven |
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Uneven VD in nitrates
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- large veins are dilated --> increased venous capacitance and decrease preload = dec heart WL
- arterioles and precap sphincters dilated less, but still decrease after load **veins > arteries venodilation most |
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DOC for acute angina attack
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nitrates
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Good and bad effects of nitrates
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GOOD
- decreased pre/after load = decreased cardiac workload BAD - can increase cardiac workload - decrease BP --> increase symp activity (baroreflex) --> increase HR and contractility **this reflex tachycardia will shorten the time for diastolic perfusion |
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Two mechanisms for anginal relief with nitrate therapy
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1. Predominant relief mechanism:
**decrease 02 requirement - lg vein dilation = decreased preload and cardiac work 2. Secondary relief mechanism: - redistribute coronary blood flow from normal to ischemic areas (even though total flow remains the same) |
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Other uses for nitrates (3)
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1. relax other smooth muscles (bronchi, GI, GU)
2. methemoglobin formation for reversing cyanide poisoning 3. viagra |
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Routes of administration of nitrates and key points
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1. Oral
- rapidly metabolized (high first pass) 2. Sublingual - preferred for rapid absorption * avoids hepatic destruction (nitroglycerin and isosorbide dinitrate) *nitroglycerin = rapid onset and short duration 3. Inhalation *fastest acting 4. Transdermal |
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Adverse effects of nitrates (2)
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1. Acute toxicity
- high VD leading to orthostatic hypotension, tachycardia, and *throbbing headaches* 2. Tolerance - **NOT GOOD FOR LONG TERM TX** |
