antihypertensive drugs

Question 1

hypertension

Answer 1

BP 140/90 mmHg

primary (>90%)
secondary –> specific cause (<10%)

• check for renal aa. stenosis –> low blood flow to kidneys –> mistake as low BP –> renin-angiotensin –> high BP –> treatable

Question 2

complications of hypertension

Answer 2

congestive heart failure
ischemic heart disease
MI
renal damage
stroke

Question 3

mechanisms for BP regulation

Answer 3

decrease in BP:

increase sympathetic activity
- activate B1-AR –> increase cardiac o/p
- activate A1 in SM –> increase peripheral resistance

decreased renal blood flow
- decrease GFR –> salt and water retention –> increase blood vol

• activate RAA
• Ang II increase peripheral resistance
• aldosterone increase salt and water retention

Question 4

factors influencing BP

Answer 4

Cardiac o/p
(contractility, HR, filling pressure – blood vol, venous tone)

and

peripheral resistance (arteriolar tone)

Question 5

drugs used in hypertension

Answer 5

diuretics

beta-1 blocker

ACE (angiotensin converting enzyme) inhibitor

Ca2+ channel blockers

Question 6

diuretics – thiazides

Answer 6

most widely used diuretic agents
eg hydrochlorothiazide

in DCT,
- inhibits NaCl cotransporter – no reabsorption
- enhance Ca2+ reabsorption – more Ca in blood
- enhance urea reabsorption, inhibit excretion –> diuretic-induced hyperuricemia

uses:
hypertension
congestive HF

AE:
- hypokalemia (in collecting duct Na exchanged w K in blood –> more K excreted)
- hyponatremia (low Na)
- hypercalcemia
- hyperuricemia (contraindication: gout)
- hyperlipidimia
- hyperglycemia

Question 7

loop diuretics

Answer 7

never for long term management of high BP

(blocks absorption of Na, K, Cl at thick AL)

VERY potent water loss

acutely remove liquid in case of pulm edema/CHF, renal failure

Question 8

beta blockers

Answer 8

propanolol – non-selective

atenolol – b1 selective

decrease rate and force –> decrease BP

usese:
hypertension, angina, following MI

AE:
bradycardia
sedation
bronchospasm (non-selective when it affects B2)
vivid dream

contraindications
- asthma, COPD
- DM –> hypog (when take too much insulin) masked
- bradycardia, arrhythmia

Question 9

ACE inhibitors

Answer 9

best antihypertensive
esp good for ppl w diabetes (when pt has hypertension/proteinuric)

LISINOPRIL
captopril
enalapril

• prevents formation of Ang II (cannot increase BP)
• prevents breakdown of bradykinin –> promotes vasodilation –> decrease BP

uses:
hypertension
cardiac failure
following MI

AE:
severe hypotension
hyperk
angioedema
excessive bradykinin –> cough
acute renal failure

contraindication: pregnancy

Question 10

ca2+ channel blockers

Answer 10

decreases ca2+ conc in blood

verapamil, diltiazem: anti-arrhythmia

nifedipine: anti-hypertension, anti-angina

AE:
constipation, headache, dizziness, flushing
severe hypotension
tachycardia