Calcium Channel blockers

Question 1

calcium channel blockers - what do they do?

Answer 1

Some act on vascular smooth muscle (VSM)
Some act on VSM and heart

Treat:
HTN
angina
cardiac dysrhythmias

Question 2

calcium channel blockers - MOA

Answer 2

1. VSM
   - block calcium channels in peripheral arterioles = > vasodilation => ↓ BP
   - block calcium channels in coronary arteries = ⇡O2 to myocardium (good for dysrhythmia)
2. Heart - same as BB
   - block calcium channels in myocardium (↓ HR, ↓ contractility)

Question 3

what part of MAP (BP) = CO x SVR does vasodilation effect?

Answer 3

CO = SV and HR
SV = stroke volume = 
 - preload
 - contractility
 - afterload (SVR)

vasodilation = ↓ SVR/after load

Question 4

Calcium channel blockers that act on vascular smooth muscle (VSM)

Answer 4

• pine

Nifedipine (Procardia, Adalat)
Amiodipine (Norvasc)
Nicardipine (Cardene)

Indications: HTN, chest pain (angina), coronary artery disease

Question 5

calcium channel blockers that act on both VSM and heart

Answer 5

Verapamil (Calan)
Diltiazem (Cardizem)

↓ HR, AV conduction and contractility (reduces the heart’s demand for oxygen)

Question 6

Nifedipine (Procardia) - MOA

Answer 6

acts only on VSM

• vasodilation of periphery => ↓ BP
• vasodilation of coronary arteries
• no action on heart

Question 7

Nifedipine (Procardia) - SE

Answer 7

• peripheral edema
• reflex tachycardia
• can be given w/Beta Blockers

Question 8

Verapamil and Diltiazem

Answer 8

CCB that act on VSM and heart
On VSM
 - vasodilation of coronary artery => ↓ BP
 - vasodilation of peripheral arterioles
 On heart
 - ↓ HR, ↓ contractility

Indications:
- dysrhythmia, HTN, angina

Question 9

Verapamil and Diltiazem: side effects and NI

Answer 9

• bradycardia
• peripheral edema
• flushing
• constipation

Pt. educ: ⇡ fluid and fiber intake, exercise
- no grapefruit juice

NI: ck HR, hold Rx if ↓ 60
ck BP, hold if <100 systolic