Nitrates and AntiAnginal Drugs Flashcards
What are the clinical uses for the Nitrate drugs?
Angina, ACS, Pulmonary edema.
What is the biochemical MOA of Nitrate drugs?
Release of NO causes increase of cGMP, leading to venodilation specifically.
Venodilation from Nitrate drugs has what positive effect on the myocardium?
Decreased Preload means less Venous Return, thereby requiring less ATP and oxygen demand of the myocardium.
How does Nitrate toxicity present?
Facial flushing, HA, Dizziness.
What is Monday Disease?
Headache + Dizziness from drop in perfusion. Associated with workers in nitroglycerin factories. Build up tolerance throughout the week but on Monday, feel the adverse effects again.
What is the MC adverse effect from Nitrates due to the drop in BP?
Reflex tachycardia, treated with Beta blocker.
What kind of MI are Nitrates absolutely contraindicated due to reliance on Preload?
Right Ventricular or Inferior MI pt should not be given Nitrates! High Yield. You drop Preload at your peril!
Why are Nitrates contraindicated in HOCM?
You want to keep Proload high so blood can flow through the obstructive narrow path in HOCM.
What 3 serious contraindications are there for Nitrates?
HOCM, anyone taking a PDE5 Inhibitor, and Right/Inferior MI.
Why is it dangerous to coprescribe a Nitrate with Sildenafil or any PDE5 Inhibitor?
PDE5 inhibitors block the breakdown of cGMP, same molecule that is enhanced by Nitric Oxide - hence obscene build up of cGMP leads to dangerous drop in blood pressure.
Why do we use Beta blockers with Hydralazine or Nitrates?
Beta Blockers are excellent for controlling the reflex tachycardia which ensues upon arterial or venodilation. by slowing depolarization and conduction at the SA and AV nodes. Beta blockers decrease opening of L-type calcium channels and decrease intracellular calcium release.
Verapamil acts very similar to what other drug class?
Beta blockers at the nodes.
Pindolol and Acebutalol are nonselective partial Beta agonists contraindicated in what?
Contraindicated in Angina.
What is a late inward sodium current in the heart and which new drug inhibits it?
Only diseased hearts have a late inward sodium current in Phase 2 (even tho Calcium is predominant in Phase 2). Ranolazine.
Note: Increased sodium gives the Sodium -Calcium exchanger more sodium to exchange for Calcium - leading to more contractility!
When is Ranolazine used?
Treatment of refractory angina not responding to nitrates.
