B / 7 : Ca2+ channel blockers and other vasodilators

Question 1

Where can we find L-type Ca2+ channels?

Answer 1

Cardiac, skeletal and smooth muscle

Question 2

What do DHPs mostly act upon?

Answer 2

Vascular smooth muscle : causes vasodilation and decreased BP

Question 3

What do non-DHPs mostly act upon?

Answer 3

On the heart (negative inotropic, chronotropic, dromotropic action)

Question 4

What are the dihydropyridines? (4)

Answer 4

• Amlodipine
• Felodipine
• Nifedipine
• Nimodipine

(Think of Amelie Poulain falling on Nemo with a Nife)

Question 5

Dihydropiridines
- MOA
- Effect
- Indication
- SE
- ROA
- Extra

Answer 5

• Block L type Ca channels in the heart and the blood vessels
• Decreased IC Ca2+ causes decreased contractility and AP frequency, + vasodilation
• Hypertension, angina, Ischemic heart disease, Raynaud’s syndrome, migraine
• Reflex tachycardia, hypotension, dizziness, steal phenomenon
• Oral, parenteral (IV for Nimodipine)
• Nifedipine and Nimodipine are the shortest acting

Question 6

What is the dose for Amlodipine?

Answer 6

1x 5-10mg

Question 7

What is a special indication specific to nimodipine?

Answer 7

For subarachnoid bleeding

Question 8

What is a non-DHP / non vasoselective agent?

Answer 8

Verapamil

Question 9

Verapamil
- MOA
- Effect
- Indication
- SE
- ROA

Answer 9

• Cardioselective Ca2+ blocker
• Slower conduction by SA and AV nodes, decreases HR
• For supraventricular arrythmias, angina, hypertension, cluster headaches
• Hypotension, constipation, AV block, bradycardia
• Oral, parenteral

Question 10

Why is verapamil inconvenient for long term usage?

Answer 10

Because it has to be taken 3x a day

Question 11

What are the non Ca2+ channel blocker vasodilators?

Answer 11

• Dihydralazine
• Bosentan
• Sildenafil

Question 12

Dihydralazine
- MOA
- Effect
- Indication
- SE
- ROA

Answer 12

• NO releasing agent
• NO induced vasodilation
• For hypertensive crisis, pregnancy hypertension, symptomatic refractory HF
• Reflex tachycardia, angina, sodium and water retention, steal phenomenon
• Oral

Question 13

Bosentan
- MOA
- Effect
- Indication
- SE
- ROA

Answer 13

• Endothelin receptor antagonist
• Vasodilation
• Pulmonary hypertension
• Teratogenic, headache, anemia
• Oral

Question 14

Sildenafil
- MOA
- Effect
- Indication
- Contraindication
- SE
- ROA

Answer 14

• PDE-5 inhibitor
• Prevents degradation of cGMP : SM relaxation and vasodilation
• For erectile dysfunction, pulmonary hypertension
• Nitrate therapy, hypotension, HF
• Headache, dizziness, indigestion, nasal congestion
• Oral