Antianginals Flashcards
3 triggers for angina
- Physical exertion
- Mechanical stress
- Increased contractility, pulse rate and BP
What is angina?
Pain when the heart becomes anoxic (oxygen deprived)
When does anginal pain occur most often?
- At nighttime - midnight to 8 am.
Clusters of chest pain for months followed by weeks with no symptoms
What things might be a trigger for angina?
- Stress
- Cold
- Hyperventilation
Describe Typical (exertional) angina
- Coronary arteries not able to transport enough oxygen to meet myocardium demand
- Oxygen imbalance causes ischemia
- Stress, exertion, eating, etc. (block flow of blood)
- *If demand exceeds available oxygen, then necrosis occurs = myocardial infarction
Describe the amount of alpha and beta receptors in a normal coronary artery
When they are normal, mainly beta 2 receptors are present.
Epinephrine acts on what receptor and has what effect?
- Acts on both beta 2 and beta 1.
- On beta 2, it causes vasodilation ( improves bloodflow to heart)
- On beta 1, it increases demand of the heart
- On beta 2, it causes vasodilation ( improves bloodflow to heart)
Individuals with variant angina have what type of receptors in their coronary arteries?
They have more alpha 1 receptors than beta 2 receptors = vasoconstriction
What is the effect of having more alpha 1 receptors in coronary arteries than beta 2 receptors?
- Epinephrine usually increases heart rate and cardiac output but with the amount of alpha 1 receptors, also vasoconstricts the coronary arteries, reducing amount of blood delivered to heart.
- Results in lack of oxygenation due to vasospasm
EKG diagnosis of variant angina consists of what?
Elevated S-T segment which is not present in normal angina
What general categories of drugs may be used in treatment of unstable angina?
- Nitrates
- Beta blockers
- Calcium channel blockers
- Antiplatelet drugs
- Antithrombin therapy
Nitrites and Nitrates cause what?
- Relaxation of all smooth muscle
- Results in arterial and venous vasodilation
- Drugs work on endothelial cells that produce nitric oxide
- Results in arterial and venous vasodilation
What is the biochemical process behind the action of nitrites and nitrates
Nitric Oxide activates guanylyl cyclase which converts GTP to cGMP, which then causes dephosphorylation of light chain myosin (2nd messenger system)
4 general effects caused by nitrites and nitrates
- Produce vasodilation
- Decrease venous return to the heart (decrease preload)
- Decreased work
- Decrease O2 demand
Side effects of Nitrites and Nitrates
- Vasodilation = intense and fast = causes headache
- Weakness, dizziness
- Flush
- Postural hypotension and syncope = accentuated by alcohol
- Reflex sympathetic activity - tachycardia and increased peripheral resistance
a. Beta blockers are used to keep tachycardia under control - Rash
- Nitrates oxidize hemoglobin to methemoglobin
- Large doses of nitrites/nitrates for long-term use decreases oxygen-carrying capabilities
What might be the problem arising from nitrates being able to oxidize hemoglobin to methemolgobin?
Blood no longer carries oxygen well! Bad for someone who is experiencing angina
Route of administration for nitrites and nitrates
- Sublingual
- Topical
- Oral
- Transdermal
Describe the onset, duration, and purpose for amyl nitrate
- Onset
Purpose of Nitroglycerin:
Rescue drug = in office emergency kit
How is nitroglycerin administered and what is its onset?
- Administered sublingually and absorbs through mucosa
Onset: 1-3 minutes
If needed to give in case of emergency, what is the sequence of administration
Pill or metered dose spray sublingually = wait 5 minutes; re-administer up to 3 doses, then 911
Why is nitroglycerin stored in a small brown vial?
It is photosensitive
T or F, Nitroglycerin is only offered as a very rapid onset short term situational drug.
False, there is also a transdermal patch that has a longer duration (up to 12 hours). Used as part of a long-term therapy
Name the long-acting nitrates
- Isosorbide dinitrate
2. Isosorbide mononitrate
