Antihypertensives I Flashcards
What is mild hypertension?
140-159/90-99
What is moderate hypertension?
160-179/100-109
What is severe hypertension?
greater or equal to 180/110
What are the nonmodifiable risk factors of HPT? (3)
Age
Sex
Family history of early onset of CVD
What are the modifiable risk factors of HPT (3)
Dyslipidemia
Diabetes mellitus
Waist circumference: abdominal obesity
What is the waist circumference that increases risk?
Male> 102cm
Female>88cm
What are the complications of uncontrolled hypertension?
Target organ damage (TOD):
-LV hypertrophy
-Hypertensive retinopathy
-Microalbuminuria or positive urine dipsticks for albuminuria or elevated albumin creatinine ratio
-Elevated Creatinine level 9or eGFR<60ml/min)
What clinical conditions are associated with uncontrolled hypertension?
Ischaemic heart disease / MI
* Heart failure
* Stroke / transient ischemic attack(TIA)
* Chronic kidney disease
* Peripheral arterial disease
What are the recommended lifestyle modifications in HPT?
Weight reduction
Dash diet (diet approaches to stop hpt)
Lowering dietary sodium
Physical activity
Moderation of alcohol
Complete cessation of smoking
What are the factors influencing HPT?
CO X PVR =Bp
What are the classes of antihypertensives (5)
- Beta-blocking agents
- Agents acting on renin-angiotensin system
- Vasodilators
- Alpha-adrenoceptor antagonists (doxazosin)
- Calcium-channel blockers
- Agents acting on arterial smooth muscle
- Diuretics
- Centrally acting agents
Which drugs act on the arteriolar system? (2)
Hydralazine
Minoxidil
What is the MOA of Hydralazine?
Uncertain mechanism of action: relax arteries and arterioles = vasodilation =
↓peripheral resistance = ↓ BP accompanied by reflex tachycardia and ↑
CO
Hydralazine interferes with the action of what?
Interferes with the action of inositol triphosphate on Ca2+ release from the sarcoplasmic reticulum
What are the indications of Hydralazine (2)
-4th line treatment for hypertension (low doses in combination with b-blocker),
-supplementary tx in chronic cardiac failure
-Indicated for HF in patients of African origin in combination with long-acting
nitrate
Adverse effect of Hydralazine
Adverse effect: long-term use can cause immune disorder resembling SLE
MOA of Minoxidil
Direct acting vasodilator (by activating K+ channels), accompanied by tachycardia. Increases CO and Potent and long-acting vasodilator
Indications of Minoxidil
Last line unresponsive/refractory HPT
Can Minoxidil be used as monotherapy? explain
NOT used as
monotherapy, concurrent diuretic and b-blocker often required
Adverse effects of Minoxidil (2)
-marked salt and water retention (NOT for heart failure),
prescribed with a loop diuretic,
-hirsutism
List selective calcium channel blockers with mainly vascular effects
Amlodipine*
Felodipine
Lecanidipine
Nifedipine*
nimodipine
Which drug is a selective CCB with cardiac effects?
Veramipil
MOA of CCBs
L-type calcium channels
Block cellular entry of Ca
2+, through calcium channels rather than
preventing its intracellular actions
What are the 2 properties of calcium channel antagonists?
Use dependence, the most active calcium channels are more
effectively blocked
* Voltage-dependent blocking, blocking is stronger when the
membrane is depolarised, causing calcium channel opening and
inactivation
cardiac actions of CCBs (3)
Cardio-selective: Verapamil (diltiazem intermediate
selectivity)
* Antiarrhythmic affects (AV block and cardiac slowing)
* Negative ionotropic effect (contra-indicated in CCF)
Effects of CCBs on vascular smooth muscle
Dihydropyridines – amlodipine
* Reflex tachycardia due to vasodilator action
* Reduce blood pressure
* Can be used in CCF
* Coronary vasodilation - use in variant angina (cause by vasospasm)
* Other smooth muscles are also relaxed: biliary, urinary, uterine
Indications of CCBs
Hypertension: shown beneficial effects on cardiovascular morbidity
and mortality.
ROA of most CCBs
Mostly given oral with good bioavailability
Which CCB is taken IV, and for what indication?
nimodipine for special indication (subarachnoid haemorrhage)
Which CCB has a long eliminationn half-life?
Amlodipine (once daily dosing)
Which CCBs have short half life?
Nifedipine, verapamil, diltiazem, short half-lives (formulations for
once daily dosing available)
What are the adverse effects of short-acting dihydropyridines (e.g. Amlodipine)? (2)
Headaches and flushing
Adverse effects associated with chronic use of CCBs
Chronic use: ankle swelling (pedal oedema) – due to vasodilation and
increased permeability
Adverse effects of Verapimil (3)
constipation, heart block, worsening heart failure
