Calcium Channel Antagonists Flashcards
Nifedipine
1) Indications
2) Onset, Peak, & Half Life
3) Metabolism
1) "Angina pectoris Coronary vasospasm HTN Cardiac arrhythmias PVD Controlled hypotension"
2) “Onset 1-3 mins
Peak 1-3 hrs
E1/2t = 3-7 hrs
90% PB”
3) Hepatic/ Renal excretion
Nifedipine: Action
Dihydropyridine – mainly arterial vascular smooth muscle.
“Competitive binds to calcium channels in vascular smooth muscle to maintain them in the INACTIVATED CLOSED STATE tissue preventing the influx of calcium through slow L-type voltage gated Ca++ channels preventing the contraction of vascular smooth muscle cells.
↓HR, contractility, AV node conduction
Vascular smooth muscle relaxation”
Nifedipine: Adverse Effects
"Reflex tachycardia Flushing Vertigo HA Hypotension MI 2* to decreased afterload Skeletal muscle weakness constipation"
Nifedipine:
1) Contraindications
2) Caution
3) Dosage
1) “Hypersensitivity
Heart failure
Hypotension
Concomitant with grapefruit juice = inhibits CYP3A4”
2) “Potentiates NMB
Decreases anesthetic requirements
Caution with BB – can cause complete heart block”
3) “5-15mcg/kg
10-30mg PO TID”
Verapamil
1) Class
2) Action
1) “Non-dihydropyridine (phenylalkylamine) = - inotrope and chronotorpic effects = heart rate
Class IV antiarrythmic”
2) “Competitive binds to calcium channels in cardiac muscle tissues to maintain them in the INACTIVATED CLOSED STATE, preventing the influx of calcium through slow L-type voltage gated Ca++ channels preventing the contraction of vascular smooth muscle or cardiac muscle cells. (decreasing Chronotropic and Inotropic effects)
Decreasing contractility, HR and Conduction velocity.”
Verapamil
1) Indications
2) Onset & half life
3) Metabolism
1) "SVT Prinzmetals or variant angina Chronic stable angina Hypertrophic cardiomyopathy Maternal or fetal tachydysrhythmias Premature labor PIH"
2) “Onset
Verapamil: Adverse Effects
”
Verapamil:
1) Contraindications
2) Cautions
3) Dosage
1) “Hypersensitivity
Renal failure
Wide QRS tachycardia (vtach)
3) 2.5-5mg IV over 2 mins then 5-10mg in 15 to 30 mins as needed to max 20mg
Diltiazem
1) Class
2) Action
1) “Benzothiazipine (both vascular and heart)
antiarrythmic”
2) “Competitive binds to calcium channels in cardiac muscle tissues, and ARTERIOL vascular smooth muscle tissue maintaining them in INACTIVATE CLOSED STATE, preventing the influx of calcium, through slow L-type voltage gated Ca++ channels preventing the contraction of vascular smooth muscle or cardiac muscle cells.
↓HR, contractility, AV node conduction
Vascular smooth muscle relaxation”
Diltiazem
1) Indications
2) Onset, VD, & Half life
3) Metabolism
1) "Treatment of SVT HTN Control angina Bronchoconstriction Pheochromocytomas Clotting disorders"
2) “Onset
Diltiazem: Adverse Effects
"Bradycardia AV block Heart failure HA, flushing Dizziness/syncope Edema"
Diltiazem
1) Contraindications
2) Cautions
3) Dosage
1) “Hypersensitivity
