Anti-HTN drugs Flashcards

1
Q

HTN does what

A

Hypertension increases the risk of coronary thrombosis, stroke and renal failure
Controlling hypertension, which is generally asymptomatic, greatly improves prognosis
Blood pressure is an excellent surrogate marker for cardiovascular (CV) risk
Antihypertensive drugs prolong life and reduce CV risk

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2
Q

Examples of anti-hypertensive drugs

A

● Drugs targeting the renin-angiotensin-
aldosterone system (RAAS)
● Calcium channel blockers (CCBs)
● Diuretics
● Hydralazine
● Drugs targeting the sympathetic nervous
system
● Nitrates

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3
Q

Treatment strategy

A

-> A/CD rule
Angiotensin/ CCBs, Diuretics

-Thiazide diuretics and thiazide-like drugs
-Angiotensin Converting Enzyme Inhibitors (ACEIs) or
Angiotensin Receptor Blockers (ARBs)
-Long-acting Dihydropyridine Calcium Channel Blockers (CCBs)

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4
Q

BP formula

A

Blood Pressure=
Cardiac Output (CO) [Stroke vol. x HR] X Total Peripheral Resistance (TPR) [big determinant: blood vessel radius]

Decrease BP:
Decrease TPR
Decrease CO
Decrease body fluid volume

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5
Q

ANGIOTENSIN CONVERTING ENZYME INHIBITORS (ACEIs) Examples

A

enalapril, lisinopril, ramipril

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6
Q

ACEIs mechanism of axn:

A

-Affect arteries and veins:
Reduce cardiac load and arterial pressure

-No effect on cardiac contractility
-Increased CO

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7
Q

ACEIs
CLINICAL USES/ indications

A

● Hypertension
● Heart failure (HF)
● Post-MI
● High risk of ischemic heart disease
● Diabetic nephropathy
● Chronic renal insufficiency to prevent
progression

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8
Q

ADVERSE EFFECTS
Of ACEIs

A

● Hypotension:
Especially after first dose and
In heart failure treated with loop diuretics, where RAAS is highly activated
● Dry cough (bradykinin accumulation)
Avoid in asthma to avoid confusion between drug- vs. asthma-related cough
● Hyperkalemia: drug-drug interactions
● Angioedema (potentially via bradykinin)
● Renal failure in renal artery stenosis
- Contraindication in renal artery stenosis and acute kidney injury
-Glomerular filtration maintained by ATII- mediated vasoconstriction (efferent arterioles)
-Hyperkalaemia may be severe due to reduced aldosterone secretion
-Reversible if caught early and ACEIs discontinued

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9
Q

ANGIOTENSIN RECEPTOR BLOCKERS (ARBs)
Examples

A

-losartan, valsartan

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10
Q

ARBs MoA

A

•Behave similarly to ACEIs in clinical practice
-Similar effectiveness on BP reduction and CV
outcomes

Similar side effect profile
Minus the cough
ACEIs and ARBs are contraindicated in pregnancy

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11
Q

ACEIs and ARBs
Contraindications

A

pregnancy

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12
Q

Low renin populations

A

●Elderly
●Afro-Caribbean descent

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13
Q

CLINICAL USES
Of ARBs

A

•HTN especially in:
- young pts (have higher renin)
-Diabetic pts
- HTN complicated by LV hypertrophy

• Heart failure

•Diabetic neuropathy

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14
Q

. RENIN INHIBITORS
Example

A

. aliskiren

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15
Q

‘RENIN INHIBITORS
MoA

A

Lowers blood pressure but
Clinically somewhat unsuccessful

Only used if it’s options don’t work

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16
Q

RENIN INHIBITORS

-Adverse effects

A

Diarrhea
Acute renal failure
Angioedema and severe allergic reactions (rare)

17
Q

RENIN INHIBITORS
Contraindications

A

Pregnancy like
ACEIs, ARBs, renin inhibitors

18
Q

-CALCIUM CHANNEL BLOCKERS (CCB)

Effects on blood vessels

A

•Generalized arterial/arteriolar dilatation
•Reduce blood pressure
-Can be offset by reflex increase in sympathetic (SNS) activity secondary to vasodilator action
•Little effect on veins
•Cause coronary vasodilation
-Useful in variant angina

19
Q

Effects on heart
(CCB)

A

•Decrease heart rate and force of contraction
•May cause AV block and cardiac slowing by effects on conducting tissue
•May excessively decrease CO
(Pts. W/ ❤️ failure CANNOT take these)

20
Q

‘3 main classes of Ca2+ channel blockers with preferential action locations:

A

•vessels vs. heart
•Bind the a1 subunit in LTCC
•Show ‘use dependence’

21
Q

Types of CCB

A
  1. DIHYDROPYRIDINES (nifedipine, amlodipine)
  2. Phenylalkylamine (Verapamil)
  3. BENZOTHIAZEPINES (Diltiazem)
22
Q

DIHYDROPYRIDINES Examples

A

nifedipine, amlodipine

23
Q

DIHYDROPYRIDINES
MoA

A

•Act mainly on arterial resistance vessels (arterioles) •Produce vasodilation
● Lower TPR which leads to Lower afterload on heart
•Typically cause reflex tachycardia
•Do not worsen CV mortality in severe but stable congestive heart failure

24
Q

Phenylalkylamine example

A

Verapamil

25
Q

Phenylalkylamine MoA

A

•Acts mainly on cardiac myocytes
• lower HR and lower force of contraction
● Strongest inotropic effects by blocking
phase 2 plateau

26
Q

Phenylalkylamine CI

A

-Contraindicated in HF

27
Q

Phenylalkylamine clinical uses

A

Clinical uses: angina, arrhythmias (not in the presence of HF), hypertension

28
Q

BENZOTHIAZEPINES
Ex.

A

Diltiazem

29
Q

BENZOTHIAZEPINES MoA

A

•Acts on both cardiac and vascular myocytes
•Little or no change in heart rate

30
Q

BENZOTHIAZEPINES clinical uses

A

Clinical uses: angina, hypertension
Not in the presence of HF

31
Q

DIHYDROPYRIDINES

Clinical uses:

A

Clinical uses: angina (dilation of coronary arteries), hypertension, Raynaud phenomenon Clevidipine/nicardipine: hypertensive crisis or urgency (IV)

32
Q

Adverse effects of CCB -> Dihydropyridines

A

Flushing and headache (vasodilator action)
Reflex tachycardia
Contraindicated in unstable angina
Peripheral edema (ankle swelling)

33
Q

ADVERSE EFFECTS

Verapamil

A

•Constipation
-Probably due to effects on calcium channels in GI nerves or smooth muscle
•Effects on cardiac rhythm (e.g. heart block) and force of contraction (e.g. worsening heart failure)
-Contraindication
-Should not normally be co-prescribed with beta-blockers (can cause AV block)

34
Q

Clinical uses of calcium antagonists

A

1.Dysrhythmias (verapamil):
- slow ventricular rate in rapid atrial fibrillation
- to prevent recurrence of SVT
2. HTN: usually a dihydropyridine drug (amlodipine)
3. To prevent angina (dihydropyridine/diltiazem)