Anti-hypertensive drugs Flashcards
What are the factors determining blood pressure?
Cardiac output (stroke volume x heart rate) ○ Heart rate ○ Contractility ○ Filling pressure Circulating blood volume Venous tone
Peripheral resistance
arterial blood pressure = cardiac output x peripheral resistance
What are the mechanisms involved in regulating blood pressure?
Neuronal:
Sympatho-adrenal
system (S)
Central regulation of S
Humoral:
RAAS
Others: NO
Local:
Intracellular calcium
How are antihypertensive drugs classified?
Diuretics
Drugs acting on RAAS: АСЕ-inhibitors АТ1 receptor blockers (ARBs) Direct renin inhibitors Aldosterone antagonists
Adrenergic agents:
Beta adrenergic blockers (BABs)
1-selective blockers
Centrally acting sympatholytic drugs
Calcium channel blockers
Vasodilators
How are diuretics classified?
Thiazides and analogs:
- Hydrochlorothiazide
- Chlorthalidone
- Indapamide
Loop diuretics:
- Furosemide
- Torаsemide
Potassium-sparing diuretics: Aldosterone antagonists ○ Spironolactone ○ Eplerenone Blockers of amilorid-sensitive sodium channels ○ Triamterene
What is the mechanism of action, clinical use, ADR of thiazides, and analogs?
Thiazides and analogs: (Hydrochlorothiazide, Chlorthalidone)
Mechanism:
○ Direct vasodilating effect (lower doses) – opening of K+ channels
○ Diuretic effect (higher doses)
Clinical use:
○ Evidence-based efficacy in hypertension – recognized as first-line therapy
○ Preferred in patients with isolated systolic hypertension and concomitant chronic
heart failure
○ Cheap drugs
ADR:
○ Potassium loss
○ Hyperuricemia (contraindicated in gout)
○ Hyperglycemia (not preferred in patients with diabetics and reduced glucose
tolerance)
○ Hyperlipidemia (↑ cholesterol and LDL)
○ Allergic reactions (cross-hypersensitivity to sulfonamides)
What is the clinical use of loop diuretics?
Loop diuretics: (Furosemide, Torаsemide)
Clinical use:
○ In emergency: hypertensive crisis
What are the clinical uses of potassium-sparing diuretics?
Potassium-sparing diuretics (Spironolactone, Eplerenone, Triamterene)
Clinical use:
○ In combination with potassium-losing diuretic to prevent potassium loss
What is the mechanism, PD, ADR, and clinical uses of indapamide?
Mechanism: ○ Vasodilation Block of Ca2+ channels PGE and PGI2 ○ Weak diuretic effect
PD
○ moderately the systolic and diastolic blood pressure
○ Neutral to carbohydrate and lipid metabolism
ADR
Mild hypokalemia
Mild hyperuricemia
Clinical use
○ Only as an antihypertensive drug
○ It is preferred in patients with concomitant diabetes
Which adrenergic drugs are used as anti-hypertensives?
Non-selective (beta1
, beta2)
-Propranolol
Selective (beta1)
- Metoprolol
- Atenolol
- Bisoprolol
Vasodilating
- Carvedilol
- Nebivolol
What is the mechanism of the antihypertensive effect of BAB?
Mechanisms of the antihypertensive effect: decreased cardiac output (beta1) ○ ↓ stroke volume ○ ↓ heart rate decreased release of renin (beta1) Pre-synaptic beta-blockade (beta2) Central effect (lipophilic BABs)
What is the mechanism counteracting the antihypertensive effect of BAB?
Mechanisms counteracting the antihypertensive effect:
Increase in the peripheral resistance (beta2) – nonselective BABs
What is the clinical use of BABs as antihypertensive drugs?
For monotherapy and combination therapy in hypertension In patients with hypertension + angina pectoris In patients with hypertension + supraventricular tachyarrhythmias In pregnancy
Which alpha-adrenergic blockers are used as antihypertensive drugs? what is their mechanism of actuon? what are the other effects and clinical uses?
Drugs
Prazosin, doxazosin
Mechanism of action
α1-block -> decrease peripheral resistance &
decrease hypertrophy of LV and vascular wall
Other effects
In prostate hypertrophy
increased HDL
Clinical use
Not recommended as first-line therapy
In combination regimens
Useful for patients with prostate hypertrophy and with diabetes
Which are the centrally acting sympatholytic drugs? what are their clinical uses?
Drugs
α2-agonists: Clonidine, Methyldopa –
presynaptic effect: release of NE
I1
(imidazolyl) agonists: Moxonidine,
Rilmenidine – in depressor regions in the
medulla
Clinical use In combination with other antihypertensive drugs In an emergency (hypertensive crises) (Сlonidine) In pregnancy (Methyldopa)
What is the pathogenic role of RAAS in hypertension?
Long-term activation
of RAAS leads to:
Elevation of blood pressure -Vasoconstriction -Na+ re-absorption and water retention LV hypertrophy Glomerulosclerosis with proteinuria