Antihypertensive Flashcards
What do calcium channel blockers do?
Selectively inhibit Ca++ ions at L type Ca channnels
Reduce myocardial O2 demand by decreasing afterload and coronary vasodilation
Also decrease HR
What are the pharmacologic effect of Ca++ channel blockers?
↓ Contractility ↓ Heart Rate ↓ SA Node Activity ↓ AV Node Conduction ↓ Systemic BP -2º vascular smooth muscle relaxation
What are clinical effects of calcium channel blockers?
Peripheral Vasodilation -Decreases afterload Depression of myocardial contractility Improving myocardial ischemia -decrease demand Electrophysiologic conduction -Verapamil at the AV node(slows conduction) -Significant for anti-arrythmic effects
What are the clinical uses of calcium channel blockers?
Coronary artery spasm
Stable angina
Cerebral vasospasm
HTN
What are verapamil’s effects?
Derivative of papavarine *AV node depression* Sa node-chronotrope Negative inotrope vasodilator Also works on fast sodium channel (potentiates local)
What are the clinical uses of verapamil?
SVT tx
stable angina
Essential HTN
Maternal and fetal tachydysrhythmias ( will cross placenta)
Intra-arterial injection for cerebral vasospasm
What are the effects of nifedipine?
Vasodilator
negligible SA/AV node effects
TAchycardia
NO Myocardial depression
What are the clinical uses of nifedipine?
Angina
HTN emergencies
What effects does nifedipine have on conduction?
Myocardial depression?
No effects on either
NIfedipine is sensitive to light. T/F
T
Nifedipine has been associated with peripheral _______.
edema
Which calcium channel blocker causes the most vasodilation (especially on coronary arteries)?
Nicardipine
What are teh clinical uses of nicardipine?
perioperative HTN
Improves LV function during ishemia
Coronary Spasm
What is halflife of nicardipine?
14 minutes
What is different about nimodipine compared to nifedipine? what is it used to treat?
Lipid soluble so it will cross BBB
used to treat cerebral vasospam
What is bolus and infusion dose of nicardipine?
100-200 mcg
infusion 5mg/hour
What are the effects of diltiazem?
Slows AV node function–antiarrhythmic
coronary vasodilation
minimal myocardial depression
What are the clinical uses of diltiazem?
SVT including afib and flutter
essential HTN
Used similar to verapamil
What drugs do calcium channel blockers interact with?
Anesthetic drugs NMB Local anesthestic K containing solution Dantrolene Platelet function Digoxin ( may increase plasma concentration)
What class is clevidipine?
it is the first third generation dihydropyridine
HOw is clevidipine cleared?
plasma choliesterases
what is the halflife of clevidipine?
1 minute
What is the effect of clevidipine?
Arterial specific vasodilating effects
What are the peripheral vasodilators?
Sodium Nitroprusside (SNP) Nitroglycerin (NTG) Hydralazine Papavarine Trimethaphan Adenosine
When should you give a peripheral vasodilator?
Treat HTN crisis Maintain controlled hypotension Improve LV stroke volume -CHF -Regurgitant valves
How do nitrovasodilators work?
Increase NO production which leads to increased cGMP
What are the functions of NO
Maintains CV tone, platelet aggregation, and CNS signalling
Aids in GI relaxation and immune functions