Pharmacology: angina drugs Flashcards
What are the goals of anti anginal drugs?
Reduce heart’s demand for oxygen (ie. release CO) by reducing HR and SV (preload, contractility, afterload)
Increasing coronary blood flow
What are the 3 main types of drugs to treat angina?
Nitrates
Calcium channel blockers
Beta blockers
Nitrates
- On a cellular/molecular level, how do they work?
They donate NO to SMCs
Increase guanylyl cyclase –> increased cGMP –> reduced calcium –> relaxation
Nitrates
- They cause vasodilation
- What are the 4 consequences of this
Reducing preload: peripheral venodilation
Venodilation in the heart BVs
Reduced afterload: arteriolar vasodilation –> reduced TPR
Oppose spasms
Nitrates
- Do they undergo considerable first pass metabolism?
- Implications of this?
- How to get around this?
Yes
Means they are basically inactive when taken orally
Use formulations that bypass the GIT
What are some formulations of nitrates, and their indications?
Sublinguial tablets/sprays: when needed
Transdermal patches: preventative
IV: early MI management
Nitrates:
- Can they denature when exposed to air or heat?
- Can tolerance occur from sustained exposure? How to overcome when using patch formulation?
Yes
Yes - 12 hours on, 12 hours off.
Nitrates
- What is the major drug interaction?
- Is this drug contraindicated with nitrates?
Phosphodiesterase V inhibitors (eg. sildenafil).
Yes
Nitrates
- Main ADR?
- Considerations with other drugs
- How should you take it?
Hypotension and dizziness
May be additive with other drugs
While sitting down
Nitrates
- ADR that is compensatory?
- Implications?
Compensatory tachycardia - opposes effects of nitrates
Nitrates
- Other ADRs?
Headache (likely due to change in cerebral circulation)
Flushing
2 examples of nitrates?
glyceryl trinitrate (GTN), isosorbide mononitrate
Calcium channel blockers:
- MOA?
- Example?
Reduces calcium influx into SMCs –> coronary vasodilation –> increased coronary BF to heart
Verapamil
Beta blockers
- MOA?
Other agents?
Nicorandil
Perhexiline
Ivabradine
