Cardiac Drugs Flashcards
Why is hypertension a problem even if asymptomatic?
because it causes damage to the blood vessels in the kidney, heart, and brain, which contributes to end organ damage
Epidemiologic supports the idea that what factors contribute to the development of primary hypertension?
- genetics
- psychological stress
- environmental and dietary factors
Describe the risk of end organ damage across the ranges of blood pressure.
- risk is proportional to BP elevation
- risk is lowest at 115/75 and doubles with each increment of 20/10
How is a diagnosis of hypertension made?
- based on repeated, reproducible measurements of elevated blood pressure
- take the average of 2-3 measurements from separate occasions
List the important procedural aspects required to ensure you’re obtaining accurate blood pressure readings from patients.
- patient should sit quietly for five minutes before a reading and not talk during the measurement
- patient should avoid caffeine, exercise, or smoking for at least thirty minutes before
- patient should have voided bladder
- remove all clothing covering the location of cuff placement
- use a validated device with the correct cuff size
- support the patient’s arm
- at first visit, record BP in both arms and use the arm that gives the higher reading for subsequent readings
What are the BP cutoffs for normal, elevated, HTN 1, and HTN 2?
- normal: systolic less than 120 and diastolic less than 80
- elevated: systolic of 120-129 and diastolic less than 80
- HTN 1: systolic of 130-139 or diastolic 80-89
- HTN 2: systolic over 140 or diastolic over 90
What is the recommendation for treatment or follow up for patients that meet the criteria for normal BP, elevated BP, HTN 1, and HTN 2?
- normal: evaluate yearly
- elevated: recommend healthy lifestyle changes and reassess in 3-6 months
- HTN 1: assess 10 year risk for heart disease and stroke; if less than 10% treated as elevated; if more than 10% or patient has CVD, DM, or CKD recommend lifestyle modification and 1 BP lowering medication
- HTN 2: recommend healthy lifestyle changes and 2 BP meds of different classes
Describe how African Americans are disproportionately affected by hypertension.
- higher proportion are sensitive to salt in the diet
- more like to have hypertension
- more like to have renal complications or end-stage disease due to hypertension
How does the treatment of African Americans with hypertension differ from that of whites?
African Americans typically respond well to calcium channel blockers and diuretics and don’t respond as well to ACE inhibitors, ARBs, or beta blockers
How does the pathophysiology of hypertension in older adults differ from that seen in younger populations?
- BP = CO x TPR
- in older adults, TPR tends to contribute more to hypertension
- in younger adults, CO tends to contribute more
- this can influence the drugs used to treat these two populations
What are the positive benefits of lifestyle modification in those with hypertension?
- it lowers cardiovascular risk
- and it can reduce the number and dose of antihypertensive meds required for treatment
Why is compliance a challenge when treating hypertension?
because it is not normally felt by the patient and they are asymptomatic
What is the most common cause of treatment failure for those with hypertension?
non-compliance
Which thiazide is most used in the treatment of hypertension? Why?
Chlorothalidone because of it’s long half-life and proven reduction of CVD
ACE inhibitors induce hypotension in several ways. Which BP lowering mechanism is most effective?
decreasing peripheral vascular resistance
ACE inhibitors are most effective at lowering blood pressure in which population?
- young and middle-aged Caucasians
- first choice of treatment for those with diabetes, chronic renal disease, or left ventricular hypertrophy
Which beta blockers are cardioselective?
- atenolol
- betaxolol
- bisoprolol
- metoprolol
Which beta blocker is cardioselective and has vasodilation effects?
nebivolol
Which beta blockers are noncardioselective?
nadolol and propanolol
Which beta blockers have sympathomimetic activity?
- acebutolol
- penbutolol
- pindolol
- carteolol
Which beta blockers are non-selective?
carvedilol and labetalol
Through what three mechanisms do beta blockers reduce blood pressure?
- reduce cardiac output
- reduce renin sercretion
- reduce sympathetic vasomotor tone
What roles do beta-blockers play in the treatment of hypertension?
- effective mono therapy in young Caucasians
- combined with other anti-hypertensive drugs to counteract reflex tachycardia (cause by vasodilators) and increased renin secretion (caused by thiazide and loop diuretics)
What are the adverse effects of beta-blockers?
- may worsen symptoms in patients with reduced myocardial reserve, asthma, peripheral vascular insufficiency, or diabetes
- may decrease exercise tolerance in patients with heart failure
- my predispose patients to atherogenesis by increasing plasma triglycerides and decreasing HDL-cholesterol
- may cause GI upset, insomnia, nightmares, depression, and skeletal muscle tremors
- abrupt cessation can lead to tachycardia, hypertension, angina, myocardial ischemia
How do beta-blockers affect metabolism?
- they delay recovery of normoglycemia because they inhibit epinephrine-mediated responses to hyperglycemia; therefore, they post a significant risk of new-onset diabetes
- they may also increase risk for atherogenesis by increasing plasma triglycerides and decreasing HDL-cholesterol
Why are beta-blockers no longer a first-line therapy for hypertension?
- because they pose a significant metabolic risk for new-onset diabetes
- and because they have worse CV outcomes than recommended classes of drugs
What is clonidine?
- a centrally acting a1 agonist
- drug that lowers TPR through it’s actions in the brainstem and also reduces sympathetic nerve activity in the kidneys to block renin secretion
- oral and transdermal formulations available
- known to cause sedation and dry mouth
- sudden withdrawal may lead to a hypertensive crisis with headache, tremor, abdominal pain, sweating, and tachycardia
How are a1-adrenergic antagonists used in the treatment of hypertension?
- doxazosin, prazosin, and terazosin have a1-antagonist effects
- they reduce NE-induced vasoconstriction to dilate both arteries and veins, thereby reducing BP
- have worse CV outcomes than recommended classes of HTN medications, though
- also known to cause orthostatic hypotension, especially in older adults
What role do centrally acting sympatholytic drugs have in the treatment of hypertension?
- clonidine, methyldopa, guanfacine
- all are reserved as last-line therapy because of significant CNS adverse effects
- act as agonists on a2 receptors in brainstem and reduce TPR
What drugs are recommended for treating hypertension in pregnant women?
- beta blockers (labetalol) and CCB (nifedipine) are first line
- methyldopa and hydralazine may also be used
What are the primary agents used in the treatment of hypertension?
- low dose thiazide diuretics and CCBs in African Americans and the elderly
- ACE inhibitors and ARBs in younger, Caucasian patients
Hydralazine
- a direct vasodilator with oral formulations for use in chronic antihypertensive therapy
- not used very commonly nowadays except for cases of pre-eclampsia or eclampsia
- acts on vascular smooth muscle to cause vasodilation,
- selective for arteries (doesn’t dilate veins)
- known to cause a lupus-like syndrome
Fenoldopam
a direct vasodilator that serves as an agonist for D1 receptors on arteries (no venous dilation)
Sodium nitroprusside
an IV hypertensive that dilates both arteries and veins and is used in the treatment of hypertensive emergencies
Diazoxide
- an IV hypertensive medication that is used in the treatment of hypertensive emergencies
- activates potassium channels and hyper polarizes cells, serving as a direct vasodilator of arteries
Which direct vasodilators are available in IV formulations for use during hypertensive emergencies?
- sodium nitroprusside
- diazoxide
- fenoldopam
- enalaprilat
- nicardipine
- hydralazine
What are the primary adverse effects of direct vasodilators?
- reflex tachycardia
- headaches
Minoxidil
- a direct vasodilator with selective dilation of the arteries
- unique in that it may cause hypertrichosis (excessive hair growth) and is therefore sold as a topical ointment (Rogaine) to treat baldness
