Calcium channel blocker formulations Flashcards
List the different classes of Ca-blockers
3 classes of CCBs:
- Dihydropyridines
- Non-dihydropyridines (consist of 2 of the classes)
They differ not only in their basic chemical structure, but also in their relative selectivity toward cardiac versus vascular L-type calcium channels
What are CCBs used to treat?
What are the vascular effects of using CCBs?
What are the cardiac effects of using CCBs?
Used to treat hypertension, angina and arrhythmias
Vascular effects
- Smooth muscle relaxation (vasodilation)
Cardiac effects
- Decrease contractility (negative inotropy)
- Decrease heart rate (negative chronotropy)
- Decrease conduction velocity (negative dromotropy)
Which CCB is better used for…
- smooth muscle relaxation?
- SA + AV nodes?
- myocardium?
Smooth muscle = dihydropyridines > verapamil-diltiazem
SA + AV nodes = verapamil-diltiazem > nifedipine
Myocardium = verapamil > diltiazem > nifedipine
Fill in the gaps
What are the 1st choice dihydropyridine CCBs?
What is the difference between pyridine + dihydropyridine?
What is Nifedipine used in?
What is its mode of action?
Used in hypertension, angina and Raynaud’s disease
Causes dilatation of both large and small arteries through a reduction in smooth muscle contraction in the arterial wall
Nifedipine has little net effect on cardiac contractility or conduction
Also reduces blood pressure
What are the ways to administer Nifedipine?
Sublingual (ABANDONED)
- Was used in hypertensive emergencies
- Nifedipine short-acting formulations can lead to uncontrollable decrease in BP
- Causes activation of sympathetic NS
- Causes reflex tachycardia - disadvantage in pts w/ coronary disease - esp. if left ventricular function is impaired
Immediate release (capsules)
Modified release (once daily)
Name an example of a modified-release nifedipine formulation?
How do osmotic pump delivery systems work?
Where is the coating of the tablet eliminated?
Adalat OROS (20mg, 30mg, 60mg)
24-hour controlled release oral drug delivery system in the form of a tablet, which acts as an osmotic push-pull pump releasing nifedipine
It is zero-order release
Cannot chew Adalat OROS
The coating of Adalat OROS remains intact during the gastrointestinal passage and is eliminated in the faeces
Why is amlodipine in many different forms?
It has a positive amine group which needs a acid (e.g. besylate, maleate, mesylate) to form a solid salt.
Fill in the gaps
Discuss the pharmacokinetic profile of Amlodipine
What class in verapamil in?
What is verapamil used for?
Class: phenylalkylamine CCB
Equally good for cardiac tissue + vasculature
Used for the management of essential hypertension + angina
Fill in the gaps
Discuss the pharmacokinetic profile of Verapamil.
When do adverse cardiovascular events tend to happen?
What formulatios have been designed to help with the adverse events?
In the morning hours between 6 AM and noon, when blood pressure (BP) tends to increase rapidly.
Verelan PM (CODAS–verapamil) and Covera HS (verapamil COER)
- Only antihypertensive agents with a delivery system specifically designed for nighttime dosing (once-daily).
Discuss how CODAS verapamil works as a controlled onset (delayed release), extended release delivery system.
When does release of verapamil start?
Why is there such a delay?
How does the drug diffuse out of the beads?
When is the highest plasma conc?
The highest plasma concentrations (Cmax) of verapamil between 6AM and noon.
