Vasodilators and Anti-anginal medications Flashcards
Factors that affect myocardial oxygen demand
contractility, heart rate, ventricular wall tension (preload)
Factors that affect myocardial oxygen supply
coronary blood flow, diastolic BP, coronary artery resistance, regional blood flow distribution, faster heart rate
Dilating veins causes
decreased venous return, decreased ventricular end-diastolic pressure, reduced cardiac workload
Decreasing peripheral arteriolar resistance causes
decreased vasodilation, reduced oxygen demand, reduced myocardial work
muscle contraction occurs when
voltage dependent Ca channels open and Ca comes into the cell
decreased intracellular Ca leads to
vasodilation
what causes inhibition of Ca release
alpha blockers, organic nitrates, nitrites, angiotensin receptor blockers
what inhibits breakdown of cyclic GMP
phosphodiesterase inhibitors
NO binds and activates what and has what effect
cytosolic guanylate cyclase which converts GTP to cGMP
the overall effect of cGMP is to cause what
smooth muscle relaxation by decreasing intracellular calcium levels
Nitroglycerine MOA
forms nitric oxide which activates guanylate cyclase, which increase cGMP and causes vascular smooth muscle relaxation
nitroglycerine affect on demand
reduces myocardial demand by decreasing preload because cause venous vasodilation
Nitroglycerine ADR
Headache, also hypotension, bradycardia, dizziness, syncope, reflex tachycardia
Nitroglycerine and tolerance
tolerance can develop withing 24-48 hours of continuous administration, need a nitrate free period for 10-12 hours
Some effects of nitrates
decrease ventricular volume, decrease arterial pressure, decrease ejection time, vasodilation of coronary arteries, increase blood flow to collateral arteries
Ways to administer nitroglcerine
oral, intravenous, ointment, transdermal, sublingual, spray
Proper use of nitroglycerine sublingual tablet
Sit down, take 1 tablet, wait five minutes, if no relief call 911, take second dose, if no relief take third dose; pt should not drive self to hospital
Isosorbide dinitrate (Isordil)
a long acting nitrate with same results as giving nitroglycerine itself, increases availability of NO
Isosorbide dinitrate (Isordil) use
acute andina only if pt did not respond to SL nitro, used less common but inexpensive
Isosorbide mononitrate (Imdur)
a long acting nitrate that ultimately results in release of nitric oxide
isosorbide mononitrate (Imdur) use
not used for acute angina, but chronically for pain prevention, USED REGULARLY
Isosorbide mononitrate (imdur) should not be used in patients currently taking
phosphodiesterase inhibitors (viagra, Levitra, cialis)
Nitroprusside (Nipride) MOA
peripheral vasodilation of arteries and veins*, very quick acting
Most common use for nitroprusside
hypertensive crisis
Milrinone (primacor) MOA
a selective phosphodiesterase inhibito in cardiac and vascular tissue, prevent cGMP breakdown, results in vasodilation and has inotropic effect
2 forms of milinone
short acting (2 hours) and quick acting (5-15 mins)
Main use of milrinone (primacor)
heart failure
Nesiritide (Natrecor) MOA and use
binds guanylate cyclase and increases cGMP, used for acute decompensated heart failure
3 important facts of nesiritide (Natrecor)
only available IV for short term continuous infusion, and can cause renal failure, very inexpensive
Sildenafil (viagra)
Phosphodiesterase inhibitor, 60 min onset last 2-4 hours, take with high fat meal
Sildenafil (Revatio)
phosphodiesterase inhibitor, used for pulmonary arterial hypertension
ADR of sildenafil
HA, hypotension, priapism, flushing, visual disturbances
Tadalafil (Cialis)
PDE inhibitor, erectile dysfunction, niche lasts 36 hours, expensive
Tadalafil (adcirca)
PDE inhibitor, BPH, expensive
Vardenafil (Levitra)
PDE inhibitor, erectile dysfunction, niche faster onset?
Avanafil (Stendra)
PDE inhibitor, me too, 30 min onset?
Minoxidil (Loniten, Rogaine) MOA
K channel agonist inhibits voltage gate Ca channel
Minoxidil (loniten, rogaine) use
antihypertensive but stimulates hair growth
Hydralazine (Apresoline) MOA
potent dilator of arteries, short acting, give 3-4 times a day
Hydralazine (Apresoline) uses
Hypertension, not fist line, acute hypertension, IV rapid response (5-10 min), pre-eclamsia, inexpensive
Ranolazine (Ranexa) MOA
Inhibits Na channel during cardiac repolarization, reduces Ca concentration
Ranolazine (Ranexa) use and benefit
prevent angina, doe not cause tachycardia, or hypotension, minimal ADR and well tolerated drug
contraindications of Ranolazinf(Ranexa)
hepatic impairment and CYP3A4 inhibitors, expensive
