Vasodilators and the Tx of Angina Flashcards
which drugs can be used in the tx of angina
beta blockers and Ca channel blockers
what is sudden , severe, pressing chest pain; caused by a decrease in coronary blood flow; leads to ischemia
angina
this can result from obstruction of bv ( coronary heart disease), spasm of vascular smooth muscle ( as a response to coronary artery disease)
angina
this type of ischemia does not cause cell death
transient ischemia
this type of ischemia can lead to deterioration of cardiac function
chronic ischemia
how can angina be treated
lifestyle changes, decrease oxygen demand, increase oxygen delivery ( vasodilators)
what are the three overlapping patterns of angina
effort-induced, stable, classical ( typical angina); vasospastic or variant ( prinzmental angina), and unstable angina
this type of angina is effort induced; most common form ; short lasting, heavy or burning feeling in the chest; caused by reduction of coronary perfusion due to a fixed obstruction of a coronary artery produced by atherosclerosis
classic angina
in this type of angina blood supply cannot increase due to obstruction ; heart becomes vulnerable to ischemia; relieved by rest or nitroglycerin
classic angina
this type of angina is prinzmetal, variant, vasospastic, or rest angina; uncommon pattern of episodic angina, attacks are unrelated to physical activity, HR, or bp; responds well to coronary vasodilators and Ca channel blockers
vasospastic angina
this type of angina is when chest pain occurs with increased frequency, duration , and intensity ; precipitated by progressively less effort ; not relieved by rest or nitroglycerin ; requires hospital admission
unstable angina
what are the determinants of cardiac oxygen demand
wall stress ( arterial pressure and ventricular volume), heart rate, contractility-> increase in any of these increases cardiac oxygen demand
what are the determinants of coronary blood flow
perfusion pressure ( diastolic), duration of diastole ( refill time ) coronary vascular resistance
what are the determinants of vascular tone
arteriolar tone directly controls peripheral vascular resistance ( systolic wall stress), and venous tone determines amount of blood returning to the heart ( diastolic wall stress)
how can we relax smooth muscle
1) increase cGMP 2) decrease ic Ca 3) increase cAMP 4) increase K permeability
this prevents interaction of myosin with actin
increase cGMP
this prevents activation of myosin light chain kinase
decrease ic Ca
this increases rate of inactivation of myosin light chain kinase
increase cAMP
this prevents depolarization of cell membrane
increase K permeability
what can you use to treat angina
organic nitrates, Ca channel blockers, and beta blockers, can also decrease myocardial oxygen requirement by decreasing the determinants of oxygen demand ( HR, ventricular volume, BP, and contractility)
this tx for angina causes a rapid reduction in myocardial oxygen demand ( rapid relief of symptoms); first pass metabolism
organic nitrates
MoA of this drug is enzyme activation of drug causes release of NO; NO combines with guanylyl cyclase causing an increase in cGMP
organic nitrates ie. sublingual nitroglycerin
effects of this drugs include relaxation of smooth muscle in arteries and veins -> decreases venous return to the heart, reduces arterial pressure, and relieves coronary artery spasm
organic nitrates
what are some adverse effects of organic nitrates
tachycardia ( reflex response to decreased arterial pressure), orthostatic hypotension ( due to increased venous capacitance ), and HA; tolerance develops rapidly ; need nitrate free intervals to restore sensitivity
