Anti-Hypertensive Drugs I Flashcards Preview

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Flashcards in Anti-Hypertensive Drugs I Deck (60):
1

Name the major classes of diuretics used to treat HTN.

-Thiazides (Hydrochlorothiazide, chlorthalidone))
-Loop Diuretics (furosemide)
-K sparing diuretics (spironolactone)

2

Name the major classes of RAAS inhibitors used to treat HTN.

-ACE inhibitors (lisinopril)
-Angiotensin receptor blockers (losartan)

3

Name the major classes of vasodilators used to treat HTN.

-Direct acting (Nitroprusside, Hydralazine)
-Calcium entry blockers (Verapamil)

4

Name the major types of sympatholytics used to treat HTN.

-Act within CNS (clonidine)
-Act on autonomic ganglia (trimethaphan)
-Act on post-ganglionic neurons (reserpine)
-Block peripheral adrenergic receptors (atenolol, prazosin, labetolol)

5

What is Lisinopril (Prinivil™, Zestril™; also captopril, enalapril, ramipril)?

Lisinopril is a drug of the angiotensin-converting enzyme (ACE) inhibitor class (RAAS inhibitor) used primarily in treatment of hypertension, congestive heart failure, and heart attacks, and also in preventing renal and retinal complications of diabetes.

Costs $4 to $56 per month

6

To what drug class does Lisinopril belong?

Pharmacologic class => ACE inhibitor
Therapeutic class => antihypertensive, treatment of CHF, preserving renal function, preserving LV function after MI, acute management of MI

7

Describe the pharmacodynamics of Lisinopril.

-Inhibits conversion of AT I to AT II by ACE
- Diminishes both vasocontriction and stimulation of aldosterone secretion by AT II

8

Describe the pharmacokinetics of Lisinopril.

- Well absorbed
- Onset 1 h, peak 6 h, duration 24 h
- Taken once a day is fine
- Excreted primarily in urine as unchanged drug

9

What toxicity is associated with Lisinopril?

- Orthostatic hypotension
- Use with caution in patients with impaired renal function, or renal artery stenosis
- Be careful in patients on diuretics, or those with aortic stenosis
- Angioedema, cough
- Acute renal failure

10

What interactions should be noted with Lisinopril?

- Additive effects with most other antihypertensives
- NSAIDs may reduce ability to lower BP
- Hyperkalemia with KCl

11

What special considerations should be made with patients on Lisinopril?

-Often discontinue diuretics prior to beginning use to reduce hypotension
- Category C/D in pregnancy, abnormal cartilage development

12

Describe the indications/dose/route for Lisinopril.

- Begin 10 mg per day, titrate slowly upward to 40 mg per day max

13

What should be monitored in patients on Lisinopril?

BP, weight, edema, K, BUN, creatinine

14

What is Hydrochlorothiazide (HydroDiuril™; also chlorthalidone)?

Hydrochlorothiazide is a diuretic drug of the thiazide class that acts by inhibiting the kidneys' ability to retain water. This reduces the volume of the blood, decreasing blood return to the heart and thus cardiac output and, by other mechanisms, is believed to lower peripheral vascular resistance.

It is on the World Health Organization's List of Essential Medicines, a list of the most important medications needed in a basic health system.

Costs $4-$50 per month

15

To what drug class does hydrochlorothiazide belong?

Pharmacologic class => thiazide diuretic

Therapeutic class => diuretic, antihypertensive

16

Describe the pharmacodynamics of hydrochlorothiazide

- Block reuptake of Cl and Na from tubular fluid after glomerular filtration
- Cause decrease in SVR (unclear mechanism)
- Lowers BP by up to 10-15 mm in many patients
- Useful as monotherapy or in combinations
- HCTZ most commonly used, but chlorthalidone may be more effective

17

Describe the pharmacokinetics of hydrochlorothiazide

- F ~70%, excreted unchanged in urine
- Short half-life (hours)
- HCTZ not available in IV formulation
-Onset 2 h, peak 5 h, duration 10 h

18

What toxicity is associated with hydrochlorothiazide?

- Allergy to sulfa antibiotics
- Cause K and Mg depletion
- Cause Na and Cl depletion => metabolic alkalosis
- Volume depletion
- Worsen hyperuricemia

19

What interactions should be noted in patients on hydrochlorothiazide?

Additive effects with most other antihypertensives

20

What special considerations should be made for patients on hydrochlorothiazide?

- More side effects in geriatric patients
- Pregnancy Class D
- Much less effective in patients with reduced GFR

21

Describe the indications/route/dose for hydrochlorothiazide.

- 12.5 mg or 25 mg po every morning
- Little benefit (and more toxicity) when given in higher doses

22

What should be monitored in patients on hydrochlorothiazide?

BP, weight, edema, K, Mg, BUN, creatinine

23

What is losartan (CoZaar™)?

Losartan is angiotensin II receptor antagonist drug used mainly to treat high blood pressure, especially for patients under 55 who cannot tolerate an ACE inhibitor

24

To what drug class does losartan belong?

Pharmacologic class => angiotensin-1 receptor blocker (ARB)

Therapeutic class => antihypertensive, preserve renal function, treatment of CHF

25

Describe the pharmacodynamics of losartan.

- Block stimulation of AT I receptor by angiotensin II => reducing vasoconstriction and production of aldosterone

26

Describe the pharmacokinetics of losartan.

- F ~30%
- Onset 6 h
- Extensive first pass effect
- Active metabolite is 40x more potent, much longer half-life

27

What toxicity is associated with losartan?

- Dizziness
- Orthostatic hypotension
- Worsening of renal failure

28

What interactions should be considered for patients on Losartan?

Additive effects with most other antihypertensives

29

What special considerations should be noted in patients on Losartan?

- Pregnancy class C/D
- Use care in patients on diuretics, those with renal artery stenosis, those with mitral or aortic stenosis

30

What is the indication/dose/route for Losartan?

For HTN, daily doses 25-100 mg q day

31

What should be monitored in patients on Losartan?

BP, weight, edema, lytes, BUN, creatinine

32

What is Nitroprusside (Nipride™, Nitropress™)?

Nitroprusside (sodium nitroprusside) acts as a drug by releasing nitric oxide.

It belongs to the class of NO-releasing drugs and is used as a vasodilator to reduce blood pressure.

33

To what class does Nitroprusside belong?

Pharmacologic class => vasodilator

Therapeutic class => antihypertensive, management of severe CHF, management of pulmonary hypertension, produce controlled hypotension to reduce bleeding during surgery

34

Describe the pharmacodynamics of Nitroprusside.

- Acts “directly” on vascular smooth muscle to cause dilatation of both veins and arterioles
- Metabolized to release CN- and NO, which activates guanylate cyclase, leads to production of cGMP from GTP, which then leads to vasodilation
- cGMP then hydrolyzed to GMP by PDE

35

Describe the pharmacokinetics of Nitroprusside.

- Only route is iv
- Rapid onset (minutes) and cessation (minutes), thereby allowing minute-by-minute titration
- CN- metabolite is converted to SCN in liver, then excreted in urine
- Must be given by continuous infusion

36

What toxicity is associated with Nitroprusside?

- Excessive hypotension
- Accumulation of CN- and thiocyanate
- Headache
- Decreased blood flow to brain

37

What interactions should be considered for patients on Nitroprusside?

Additive effects with most other antihypertensives

38

What special considerations should be made for patients on Nitroprusside?

- Monitor patient VERY closely—must be in ICU with arterial line
- Avoid high infusion rates or prolonged infusions, to prevent accumulation of CN-
- Use with caution in patients with increased intracranial pressure

39

What is the indication/route/dose for Nitroprusside?

- For treatment of hypertensive crisis
- Given as IV infusion at 0.3-10 mcg/kg per minute

40

What should be monitored in patients on Nitroprusside?

BP, HR, metabolic acidosis; most often requires arterial line

41

What is Hydralazine (Apresoline™)?

Hydralazine is a direct-acting smooth muscle relaxant used to treat hypertension by acting as a vasodilator primarily in arteries and arterioles. By relaxing vascular smooth muscle, vasodilators act to decrease peripheral resistance, thereby lowering blood pressure and decreasing after load.

It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.

$4 per month or more for branded

42

To what drug class does hydralazine belong?

Pharmacologic class=> peripheral vasodilator

Therapeutic class=> antihypertensive, treatment of CHF, vasodilator

43

Describe the pharmacodynamics of hydralazine.

- “Direct” acting vasodilator
- Seems to act by inducing endothelium to produce NO, which then passes to SM cells and induces production of cGMP, minimal venodilating effect

44

Describe the pharmacokinetics of hydralazine.

- Given po, im, or IV
- Metabolized extensively in GI mucosa and in liver, eventually excreted as metabolites in urine
- F ~40%
- Onset 30 after po dose, 10 min after iv dose
- Persists for 2-6 hours

45

What toxicity is associated with hydralazine?

- More dangerous in patients with renal disease, prior stroke, angina
- Watch for hypotension, edema, occasionally drug-induced lupus

46

What interactions should be noted for patients on hydralazine?

Additive effects with most other antihypertensives

47

What special considerations should be made for patients on hydralazine?

- Never use as chronic oral monotherapy for treatment of hypertension, since edema and reflex tachycardia will result
- Concern giving to patients with CAD

48

What is the dose/route for hydralazine?

- Dose 10-50 mg po four times daily

49

What should be monitored in patients on hydralazine?

BP, weight, edema, BUN, creatinine, symptoms of lupus or angina

50

What is Verapamil (Isoptin™, Calan™, similar to nifedipine, amlodipine, diltiazem, nicardipine)?

Verapamil is an L-type calcium channel blocker of the phenylalkylamine class. It has been used in the treatment of hypertension, cardiac arrhythmia, and most recently, cluster headaches.

It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.

Costs $4 to $86 per month

51

To what drug class does verapamil belong?

Pharmacologic class => calcium entry blocker

Therapeutic class => antihypertensive, antianginal, antiarrhythmic

52

Describe the pharmacodynamics of verapamil.

- Reduces BP by inhibiting influx of calcium through “slow channels” => dilating peripheral arterioles
- Produces negative inotropic effect as well
- For angina, reduces afterload, thus decreasing oxygen consumption
- Inhibits spasm of coronary arteries in vasospastic angina; blocks reentry paths through AV nodes in paroxysmal SVT

53

Describe the pharmacokinetics of verapamil.

- Absorbed rapidly, but F ~30%
- Also available in SR tablets
- Cleared by kidney and liver (produces active metabolites)
- Onset 2 h po, 1-5 min iv
- Half-life 6-12 h
- May be given po or iv

54

What toxicity is associated with verapamil?

Hypotension, AV block, worsening of CHF, bradycardia

55

What interactions should be noted for patients on verapamil?

- Additive effects with most other antihypertensives
- Additive toxic effects on heart when given with beta-blockers

56

What special considerations should be made for patients on verapamil?

- Use reduced doses in patients with both renal and hepatic disease
- Short-acting nifedipine (and similar CEBs) can increase risk of MI (unclear why)
- Pregnancy C

57

What is the dose/route for verapamil?

80 mg thrice daily, or 240 mg SR once daily

58

What should be monitored in patients on verapamil?

weight, edema, BP

59

Which drug is generally given as a first line treatment for HTN?

A thiazide diuretic

(Also ACEI, ARB, or CEB may be good initial drugs)

60

Which drugs have a differential efficacy in African-American patients?

Diuretics and CEBs are more effective than beta-blockers, ACEI, or ARBs