Antihypertensives Flashcards
Antihypertensives have 3 targets of therapy
heart
kidneys
arterioles/venules
What do Ca channel blockers do?
- Block L-type channels
- Reduce myocardial O2 demand
- decrease afterload
- coronary vasodilation
- Decrease HR
Whatr are the types of Ca blockers?
PHENYLALKYLAMINES
Verapamil
DIHYDROPYRIDINES
Nicardipine, etc..
BENZOTHIAZEPINES
Diltiazem
These Ca blockers physically occlude channel after binding to receptor when in open state…AV Node.
Phenylalkylamines…verapamil
These Ca blockers prevent Ca entry into channel by altering channel structure…peripheral arterioles.
Dihydropyridines…”-pines”
These Ca blockers work like ”magic”…mechanism unknown…other effects include inhibition of Na-K pump and inhibition of calcium-calmodulin binding…AV Node selective
Benzothiazepines…Diltiazem
What are the pharmacologic effects of Ca blockers? (5)
↓ Contractility
↓ Heart Rate
↓ SA Node Activity
↓ AV Node Conduction
↓ Systemic BP –2º vascular smooth muscle relaxation
What are the clinical uses of Ca blockers? (4)
Coronary Artery Spasm
Stable Angina
Cerebral Vasospasm
HTN
What is the better treatment for coronary spasm?
nitrate with Ca blocker
Name the phenylalkamines.
Verapamil
Name the 1,4 dihydropyrimidines. (6)
Nifedipine
Nicardipine
Nimodipine
Isradipine
Felodipine
Amlodipine
Note: All end in -ipine
Name the benzothiazepines.
Diltiazem
What is verapamil? (3)
Derivative of papavarine
Phenylalkylamine
Also works on fast sodium channels–potentiates LA
How does verapamil work? (4)
AV Node depression
SA Node– (-) chronotrope
Negative Inotrope
Vasodilator–not as much as other Ca blockers
What are the clinical uses for verapamil?
- SVT Treatment
- Stable Angina
- Essential HTN
- Maternal and Fetal Tachydysrhythmias–may decrease uterine blood flow
- Intra-arterial injection for cerebral vasospasm,
Will verapamil affect the placenta?
yes
What is the concern with intra-arterial injection of verapamil for cerebral vasospasm?
Problem with decreased BP so may need to inject NE as well
What does nifedipine do?
VASODILATOR
negligible SA/AV node–not good for arrhythmias
Tachycardia
Myocardial depression
What drug should you NOT use for LV failure pts to treat HTN and is light-sensitive?
Nifedipine
What HTN drug works mainly arterially with some venous effect?
Nifedipine
What are the good effects of nifedipine?
Profound vasodilation
No myocardial depression
No conduction effects
What are the clinical uses of nifedipine?
Angina–although better drugs exist
HTN EMERGENCIES
What are the bad effects of nifedipine? (3)
No IV prep (light)
Severe hypotension
Peripheral edema
What are the effects of nicardipine?
VASODILATION
No effect on SA/AV Node
No myocardial depression
