Antihypertensive medication 2 Flashcards
Calcium channel blockers are the first line treatment for hypertension in?
Elderly
Where are the calcium channels found?
1) Heart
2) Blood vessels
Are calcium blockers safe in renal failure?
Yes (along with clonidine “sympatholytic”, and others)
What is the use of calcium channel blockers?
- They’re useful in hypertension as they dilate peripheral arteries and decrease the TPR by relaxing the vascular smooth muscle
- They can be used alone or combined with other drugs
- Well tolerated in renal failure
What are the classes of calcium channel blockers?
1) Dihydropyridines (DHPs, like Nifedipine)
2) Phenylalkylamines (verapamil)
3) Benzothiazepines (diltiazem)
What are the different drugs under dihydropyridine?
1) Nifedipine
2) Amlodipine
3) Nitrendipine
4) Nisoldipine
5) Nicardipine
6) Isradipine
What is the mechanism of action of the dihydropyridine calcium channel blockers?
They work on the BV more than the heart, causing vasodilation, which will lead to reflex tachycardia as they don’t work much on the heart
What are the drugs under phenylalkylamines?
Verapamil
What is the mechanism of action of phenylalkylamines?
Blocks the calcium channel in the heart mainly and to a small extent in the blood vessels, and thus it has an important effect on tachyarrhythmias, making it an anti-arrhythmic, vasodilating, and cardio-suppressive drug.
What are the drugs under benzothiazepines?
Diltiazem (the only one used clinically)
What is the mechanism of action of benzothiazepines?
same same phenylalkylamines
What are the commonly used calcium channel blockers?
1) Nifedipine
2) Amlodipine
3) Felodipine
4)Verapamil (auses gingival hyperplasia)
5) Diltiazem
6) Clevidipine (formulated for IV only)
What is the site of action of dihydropyridines?
They act mainly on the smooth muscles of the blood vessels, resulting in coronary vasodilation, which is associated with reflex tachycardia (amlodipine reflex tachycardia is milder than nifidepine) and increased CO
When is dihydropyridine used?
Hypertension
What is the site of action of verapamil (phenylalkylamine)?
It affects all calcium channels but mainly those of the heart, causing vasodilation and slowing the AV conduction reducing the force of contraction of the heart
When is phenylalkylamine used?
1) Hypertension
2) Angina
3) In some SVTs
What is the site of action of diltiazem?
With an intermediate property, it results in vasodilation and depresses the AV conduction mildly with mild inotropic effects
When is diltiazem used?
1) Angina
2) In some Arrhythmias