CCB

Question 1

Nifedipine (Adalat)

Answer 1

CCB
Dihydropyridine
more vascular selective

Uses;

• Tx angina (stable and variant)
• Tx HTN
• cardiac arrhythmias
• coronary artery and peripheral vasodilation
• controlled hypotension
• blunt SNS response

MOA;

• binds to the VGCa channel and maintains it in the closed inactive state inhibiting Ca influx into the cardiac and vascular smooth muscle
• decreased intracellular Ca; vascular smooth muscle relaxation and decreased BP

Dose; IV 5 - 15 mcg/kg

Pharmacokinetics;
-IV onset; 1 - 3 min
-peak; 1 -3 hours
-E1/2t; 3 -7 hours (longer in elderly and liver dysfunction)
-Pb; 90%
metabolized by the liver and cleared by the kidneys

Side Effects

• reflex tachycardia
• hypotension
• palipations
• flushing
• headache
• peripheral (leg) edema

Contraindicated

• heart failure
• severe hypotension
• severe aortic stenosis

Caution

• CCB decrease anesthetic requirement by 25%
• potentiate NMBD

Question 2

Verapamil

Answer 2

Phenylalkamine
Non-dihyropyridine 
CCB
more cardiac selective
(primary site of action AV node) 

Uses;

• tx HTN
• tx SVT
• tx A-fib/A- flutter
• tx Variant/ Stable angina
• tx hypertrophic cardiomyopathy
• tx maternal/ fetal tachydysrhythmias
• tx preterm labor

MOA;

• blocks the VGCa channel in the closed inactive state and blocks the influx of Ca into the cardiac and vascular smooth muscle
• decreases HR, contractility, and conduction velocity (AV node)
• terminates dysrhythmias by decreasing nodal conduction
• negative chronotropic effect on SA node
• negative inotropic effect on myocardial muscles
• moderate coronary/ systemic artery dilation

Dose; 2.5 - 5 mg over 2 min followed by 5 - 10mg in 15 - 30 min as needed to a max. of 20 mg

Pharmacokinetics;

• peak; 15 min (IV)
• E1/2t; 6 - 12hrs
• Pb; 90%
• metabolized by the liver into an active metabolite norverapamil
• 70% excreted unchanged in the urine (after IV dose)

Side Effects;

• hypotension
• arrhythmias
• exacerbation of HF
• nausea
• constipation
• facial flushing
• syncope
• dizziness
• headache
• gingival hyperplasia

Contraindicated;

• severe bradycardia
• HF
• AV block
• LV dysfunction
• Sick Sinus Syndrome
• co-administration of BB
• Wolf Parkinson White Syndrome

Caution

• hx of MH; CCB and Dantrolene cause hyperkalmeia
• increased risk of LA toxicity with CCB
• H2 antagonists can alter CCB plasma level
• CCB can increase diid plasma level
• CCB potentiate NMBD
• CCB decrease anesthetic requirement

Question 3

Diltiazam

Answer 3

Benzothiazepine,
Non-dihyropyridine
CCB

Uses;

• SVT (blocks reentry)
• HTN
• Angina

MOA;

• blocks L-type VGCa channel and inhibits the influx of Ca into cardiac and vascular smooth muscle
• acts on SA and AV node; decreases HR, decreases contractility and decreases conduction velocity
• dilates coronary, cerebral and systemic arteries
• blocks activation of the Ca slow channel (that would cause coronary spasm, bronchoconstricition)

Dose; IV; 0.25 mg/kg over 2 min; after 10 - 15 min can be followed by 1 additional PRN dose of 0.35 mg/kg
(for SVT)

Pharmacokinetics;
-Oral onset; 15 min
-Peak; 30 min 
-E1/2t; 4 - 6 hrs
-Vd; 300L
-Pb; 70 - 80%
-metabolized by the liver
PO huge 1st pass effect; 20% bioavailability
-Primary Excretion through the liver (75%) 
-then kidneys 35%  

Side Effects;

• decrease HR
• AV block
• Heart failure
• syncope
• headache
• dizzy
• flushing
• constipation
• peripheral edema
• gingival hyperplasia

Contraindicated

• HF
• Heart block
• Sick sinus syndrome
• hypotension (SBP <90)