Antihypertensives (Ca Channel Blockers) - Week 2

Question 1

4 functions of Ca in the body

Answer 1

• signal transduction in CNS and heart
• musc contraction: smooth, cardiac, and vessel walls
• bone health
• clotting cascade

Question 2

3 primary actions of CCB’s

Answer 2

• negative inotropic effect
• negative dromotropic effect (AV conduction block)
• vasodilation of systemic, splanchnic, coronary, and pulm beds

Question 3

Dihydropyridines vs non-dihydropyridines

Answer 3

dihydropyridines

• “-ipine”
• strictly arterial vasodilators
• used as anti-HTNs

Non-dihydropyridines

• verapamil and diltiazem
• negative inotropes, neg dromotropes, and vasodilators.

Question 4

Advantages of Nicardipine

Answer 4

• (dose dependent) Potent arteriole specific vasodilator of systemic, coronary, and cerebral circulations w/o important negative inotropic or dromotropic effects
• no coronary steal syndrome
• offers favorable myocardial O2 supply/demand
• mild natriuretic effect

Question 5

Why is Nicardipine good for emergent HTN?

Answer 5

onset <1 min, duration 15-20 min

Question 6

Why is Nicardipine useful for IV control of HTN in PACU and ICU?

Answer 6

• slower onset and offset than SNP
• easier to use
• fewer BP swings
• no rebound HTN w w/d (don’t have to taper it)
• Reflex tachycardia <10 bpm
• prolonged duration of action by a be beneficial post-op

Question 7

Disadvantages of Nicardipine

Answer 7

• may accumulate
• variable duration of action
• HoTN
• venous irritation
• may cause tachycardia

Question 8

Advantages of Clevidipine

Answer 8

• reduced need for other anti-HTNs
• reliable control
• no dose adjustments for renal/hepatic disease
• ready to use vial
• no sig myocardial depress
• no effect on preload
• low potential for drug interactions

Question 9

Clevidipine disadvantages

Answer 9

• lipid emulsion
• continuous monitoring required
• contraindicated w egg and soy bean allergy, pancreatitis, and HLD
• slower onset than nicardipine

Question 10

3 functions of verapamil (phenylalkylamine class)

Answer 10

• potent negative inotrope
• dromotrope
  vasodilator

Question 11

3 good uses for verapamil

Answer 11

• AS and IHSS
• Conversion of atrial re-entry tachyarrhythmias
• coronary artery vasospasm (Prinzmetal angina)

Question 12

_______, of the benzothiazine class, fits b/t verapamil (phenylakylamine) and dihydropyridines in action

Answer 12

Cardizem

Question 13

Uses for Cardizem

Answer 13

• rate control in a.fib and atrial tachicardia vs a conversion agent like verapamil

Question 14

Things to remember about verapamil

Answer 14

• potent neg inotrope and dromotrope
• mild vasodilator
• good for tx of vasospastic angina and essential HTN

Question 15

Things to remember about cardizem

Answer 15

• fits b/t verapamil and dihydropyridines in action
• less neg inotropic and dromotropic effects than verapamil but more than dihydropyridines
• mild vasodilator like verapamil

Question 16

Things to remember about dihydropyridines

Answer 16

• virtually pure arterial vasodilator

- lack clinically sig neg inotropic and dromotropic effects

Question 17

CNS s/e of CCBs

Answer 17

• dizziness, HA, Fatigue, insomnia, nervousness

from fluctuations in BP

Question 18

CV s/e of CCB’s

Answer 18

DHP: flushing, edema, palpitations
NDHP: bradycardia from blocking the AV node

Question 19

Resp s/e of CCB’s

Answer 19

Nasal congestion, dyspnea, cough (nifedipine mostly)

Question 20

GI and other s/e of CCB”s

Answer 20

N/V/D

arthralgias/joint stiffness, itching

Question 21

How do verapamil and diltiazem enhance myocardial O2 balance?

Answer 21

• decrease myocardial O2 consumption by after load reduction and/or neg inotropic effect
• increase O2 delivery through coronary vasodilation

Question 22

How do dihydropyridine vasodilators worsen MvO2?

Answer 22

they cause diastolic HoTN and reflex tachycardia (except nicardipine)

Question 23

T/F CCB’s decrease repercussion injury after ischemia.

Answer 23

True. b/c they decrease O2 demand.

Question 24

How do CCB’s affect renal fx?

Answer 24

increase RBF and GFR and induce natures

*Benefits can be reversed if they cause HoTN, reflex catecholamine release, and angiotensin activation leading to decreases in RBF and GFR

Question 25

T/F: CCB’s are good to use for their nephroprotective effects.

Answer 25

False.

Question 26

Should CCB’s be taken the am of surgery?

Answer 26

Yes unless they’re on cardizem because that can create some drug interactions

Question 27

Anesthetic considerations w CCB’s

Answer 27

• may potentiate the effects of NMB’s
• may enhance hypotensive, CV depressant, and vasodilation effects of anesthetics and analgesics
• use adq hydration to avoid HoTN r/t inc fluid requirements
• clevidipine reduces gastric emptying (increased risk of PONV)
• Diltiazem inc sedative effects of midazolam