Drugs Used For The Treatment Of Hypertension II: Ca++ Channel Blockers And Other Vasodilators Flashcards

1
Q

Name the Class I calcium channel blockers

A

Verapamil

Gallopamil

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2
Q

Name the Class II calcium channel blockers

A

Diltiazem

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3
Q

Name the short acting Class III calcium channel blockers

A

Nifedipine
Nicardipine
Nimodipine

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4
Q

Name the intermediate acting class III calcium channel blockers

A

Nitrendipine
Nisoldipine
Felodipine
Isradipine

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5
Q

Name the long acting class III calcium channel blockers

A

Amlodipine
Lacidipine
Lercanidipine
Manidipine

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6
Q

What receptor do calcium channel blockers work on?

A

L type voltage-gated Ca2+ channels

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7
Q

What is the result of CCBs binding to the L-type voltage gated calcium channel?

A

Depression of the heart (contraction and automaticity) and vasodilation

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8
Q

What are the pharmacokinetic properties of CCBs?

A

High plasma protein binding

Inactivation by CYP3A4

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9
Q

Which enzyme is responsible for the inactivation of CCBs?

A

CYP3A4

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10
Q

What is a pharmacodynamic property of verapamil?

A

Verapamil enhances the plasma level of digoxin - therefore they should not be given together

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11
Q

What are the serious toxicities associated with CCBs?

A

AV block
Cardiac depression
Bradycardia

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12
Q

What are the minor toxicities associated with CCBs?

A
Hypotension
Dizziness
Headache
Angioedema
Nausea 
Constipation 
Gingival hyperplasia
(Reflect tachycardia - DHP)
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13
Q

What are the contraindications of CCBs?

A

Pregnancy

Short acting DHP in IHD

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14
Q

What is the general name for the CCBs in Class I?

Are these drugs selective or non-selective?

A

Phenylalkilamines

Non-selective

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15
Q

What are the indications for Class I CCBs?

A

Angina (stable, unstable, Pritzmental)
Supraventricular arrhythmia
Hypertension

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16
Q

What is the general name of the CCBs in Class II?

Non-selective

A

Benzothiazepines

Non-selective

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17
Q

What are the clinical uses of Class II CCBs?

A

Angina (stable, unstable, Pritzmental)
Supraventricular arrhythmia
Hypertension

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18
Q

What is the general name for Class III CCBs?

Are they selective or non-selective

A

Dihydropyridines (DHP)

Vasoselective

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19
Q

How is Nifedipine administered?

A

IV
Tablet spray
Slow releasing tablets

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20
Q

What are the clinical uses of Nifedipine when administered via IV?

A

Pritzmental angina

Hypertonic crisis

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21
Q

What are the clinical indications of Nifedipine when administered via tablet spray?

A

Prevention of stroke

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22
Q

When is Nifedipine given in slow releasing tablets?

A

Long-term treatment

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23
Q

What is the clinical use of Nimodipine?

A

Subarachnoid bleeding

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24
Q

What is the clinical indication of Isradipine?

A

Arteriosclerosis

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25
Q

What is the half life of Amlodipine?

A

Long plasma half life.

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26
Q

What is the dose of Amlodipine?

A

1x 5-10 mg

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27
Q

What is the characteristic of lacidipine?

A

High lipid solubility accumulation in the lipid membrane so can be useful in the management of atherosclerosis.

Plasma T 1/2 short

28
Q

What is the characteristic of Lercanidipine?

A

High lipid solubility accumulation in the lipid membrane so can be useful in the management of atherosclerosis.

Plasma T 1/2 short

29
Q

What is the characteristic of Manidipine?

A

High lipid solubility accumulation in the lipid membrane so can be useful in the management of atherosclerosis.

Plasma T 1/2 short

30
Q

Which DHP have high lipid solubility accumulation in the lipid membrane and Plasma T 1/2 short

A

Lacidipine
Lercanidipine
Manidipine

31
Q

What are the clinical uses of DHPs?

A

Angina (stable and unstable)
Hypertension
Peripheral vascular disease (e.g., Raynaud disease)

32
Q

Name the direct acting vasodilators that work through NO

A

Hydralazine

Nitroprusside sodium

33
Q

Which direct acting vasodilator works on arteries?

A

Hydralazine

34
Q

Which direct acting vasodilator has a direct affect on the arteries?

A

Hydralazine

35
Q

What is the clinical indication of Hydralazine?

A

Preeclampsia and eclampsia in pregnancy

36
Q

Which direct acting vasodilator acts on the arterial and the venous side?

A

Nitroprusside sodium

37
Q

What is the clinical indication of Nitroprusside sodium?

A

Not used nowadays

Was used for hypertensive emergencies (administered IV)

38
Q

What are the side effects of nitroprusside sodium?

A

Cyanide toxicity

39
Q

How to differentiate between drug induced lupus and SLE?

A

Drug induced lupus will regress after removal of the drug

Anti-his tone antibodies are present only in drug induced lupus

40
Q

What are the K+ channel stimulants?

A

Minoxidil

Diazoxide

41
Q

What is the pathomechanism of K+ channel stimulants?

A

They open K+ channels causing hyperpolarazation of smooth muscle.

42
Q

What is the result of K+ channel stimulants?

A

Arteriolar vasodilation

43
Q

What are the clinical uses of Minoxidil?

A

Alopecia to promote hair growth

Severe hypertension

44
Q

When is Minoxidil given orally?

A

Only in very severe cases of alopecia

45
Q

How is Minoxidil administered in mild to moderate alopecia?

A

Topically to promote hair growth

46
Q

What are the clinical indications of Diazoxide?

A

Hypertensive crisis

Insulinoma

47
Q

Why is Diazoxide used as treatment for insulinomas?

A

Diazoxide binds to and opens K+ channels causing hyperpolarisation of the beta cell, decreased calcium influx which results in decreased insulin release.

48
Q

How is Diazoxide administered in hypertensive crisis?

A

Oral or IV

49
Q

What are the adverse effects of K+ channels stimulants?

A
Hypertrichosis (Minoxidil)
Hyperglycemia (Diazoxide)
Edema 
Reflex tachycardia
Increased cardiac O2 demand
50
Q

What is the action of Fendoldopam mesylate?

A

Dilation of renal, mesenteric and coronary arteries

51
Q

What sort of drug is Fenoldopam mesylate?

A

D1 receptor agonist

52
Q

How is Fenoldopam administered in the treatment of HTN?

A

IV infusion

53
Q

Which subunit do CCBs bind to?

A

Alpha 1 subunit

54
Q

Where does Diltiazem bind?

A

EC surface of the L type voltage gated Ca+ channel

55
Q

Where does verapamil bind to?

A

The inner cytoplasmic part of the L type voltage gated Na+ channel

56
Q

What are the clinical indications of verapamil?

A

Migraine - causes vasodilation of cerebral vessels

57
Q

Where are the L type calcium channels found?

A

Cardiac, skeletal, smooth muscle, neurons, endocrine cells and bones

58
Q

What can hydralazine be administered in combination with?

A

b blockers and diuretics

59
Q

What are the side effects of Hydralazine?

A
It increases the O2 demand on the heart
Tachycardia 
Increased renin release leading to water retention 
Headache
Vomiting
Allergic reaction
Drug induced lupus
Edema
Reflex tachycardia
60
Q

What are the side effects of diazoxide?

A

Reflex tachycardia
Can provoke angina and MI in IHD patients
It increases blood sugar and uric acid levels - so pre existing metabolic disorders are worsened.

61
Q

How does nitroprusside sodium have vasodilation effects?

A

NSP binds to hemoglobin: releasing cyanide, methemoglobin and NO.

62
Q

What is the mechanism of action of NO?

A

NO activates guanylate cyclase in vascular smooth muscle and increases intracellular production of cGMP. cGMP activates protein kinase G which activates phosphatases which inactivate myosin light chains. Myosin light chains are involved in muscle contraction. The end result is vascular smooth muscle relaxation, which allow vessels to dilate

63
Q

What is methemaglobin?

A

Hemoglobin in which the iron in the heme group is in the ferric (Fe3+) state

64
Q

How does nitroprusside cause cyanide poisoning?

A

It binds to Hb forming metHb, which binds CN- ions forming cyanomethemoglobin. Cyanomethemoglobin means that there is no CN- to inhibit complex IV of the ETC. This leads to histotoxic hypoxia as cells are unable to make ATP.

65
Q

What is the mechanism of action of sodium thiosulfate?

A

it converts cyanomethemoglobin to methemoglobin and thiocyanate

66
Q

What is the treatment of cyanoxide poisoning?

A

Sodium thiosulfate

67
Q

What is the mechanism of action of methylene blue?

A

It is used in the treatment of methemoglobinemia - it converts MetHb to oxyHb