1. Antihypertensive Agents

2. Hypertension High blood pressure
Normal: Systolic < 130 mm Hg Diastolic < 85 mm Hg

3. Classification of Blood Pressure
Category Systemic BP (mm Hg) Diastolic BP (mm Hg)
Normal <130 <85
High normal
Hypertension Stage Stage Stage Stage 4  210  120

4. Classification of Blood Pressure
Primary Hypertension
Specific cause unknown
90% of the cases
Also known as essential or idiopathic hypertension
Secondary Hypertension
Cause is known (such as eclampsia of pregnancy, renal artery disease, pheochromocytoma)
10% of the cases

5. Blood Pressure = CO x SVR
CO = Cardiac output
SVR = Systemic vascular resistance

6. Instructors may want to insert EIC Image #69: Blood Pressure: Normal Regulation

7. Antihypertensive Agents
Medications used to treat hypertension

8. Antihypertensive Agents: Categories
Adrenergic agents
Angiotensin-converting enzyme inhibitors
Angiotensin II receptor blockers
Calcium channel blockers
Diuretics
Vasodilators

9. Antihypertensive Agents: Categories
Adrenergic Agents
Alpha1 blockers
Beta blockers (cardioselective and nonselective)
Centrally acting alpha blockers
Combined alpha-beta blockers
Peripheral-acting adrenergic agents

10. Antihypertensive Agents: Mechanism of Action
Adrenergic Agents
Alpha1 Blockers (peripherally acting)
Block the alpha1-adrenergic receptors
The SNS is not stimulated
Result: DECREASED blood pressure
Stimulation of alpha1-adrenergic receptors causes HYPERtension
Blocking alpha1-adrenergic receptors causes decreased blood pressure

11. Antihypertensive Agents:
Adrenergic Agents
Alpha1 Blockers
doxazosin (Cardura)
prazosin (Minipress)
terazosin (Hytrin)

12. Antihypertensive Agents: Mechanism of Action
Adrenergic Agents
Central-Acting Adrenergics
Stimulate alpha2-adrenergic receptors
Sympathetic outflow from the CNS is decreased
Result: decreased blood pressure

13. Antihypertensive Agents:
Adrenergic Agents
Central-Acting Adrenergics
clonidine (Catapres)
methyldopa (Aldomet) (drug of choice for hypertension in pregnancy)

14. Antihypertensive Agents: Mechanism of Action
Adrenergic Agents
Adrenergic Neuronal Blockers (peripherally acting)
Inhibit release of norepinephrine
Also deplete norepinephrine stores
SNS (peripheral adrenergic nerves) is not stimulated
Result: decreased blood pressure

15. Antihypertensive Agents:
Adrenergic Agents
Adrenergic Neuronal Blockers (peripherally acting)
reserpine
guanadrel (Hylorel)
guanethidine (Ismelin)

16. Antihypertensive Agents: Adrenergic Agents
Therapeutic Uses
Alpha1 blockers (peripherally acting)
Treatment of hypertension
Relief of symptoms of BPH
Management of of severe CHF when used with cardiac glycosides and diuretics

17. Antihypertensive Agents: Adrenergic Agents
Therapeutic Uses
Central-Acting Adrenergics
Treatment of hypertension, either alone or with other agents
Usually used after other agents have failed due to side effects
Also may be used for treatment of severe dysmenorrhea, menopausal flushing, glaucoma
Clonidine is useful in the management of withdrawal symptoms in opioid- or nicotine-dependent persons

18. Antihypertensive Agents: Adrenergic Agents
Therapeutic Uses
Adrenergic neuronal blockers (peripherally acting)
Treatment of hypertension, either alone or with other agents
Seldom used because of frequent side effects

19. Antihypertensive Agents: Adrenergic Agents
Side Effects
Most common: dry mouth drowsiness sedation constipation
Other: headaches sleep disturbances nausea rash cardiac disturbances (palpitations)
HIGH INCIDENCE OF ORTHOSTATIC HYPOTENSION

20. Antihypertensive Agents: Categories
Angiotensin-Converting Enzyme Inhibitors
(ACE Inhibitors)
Large group of safe and effective drugs
Often used as first-line agents for CHF and hypertension
May be combined with a thiazide diuretic or calcium channel blocker

21. Antihypertensive Agents: Mechanism of Action
ACE Inhibitors
RAAS: Renin Angiotensin-Aldosterone System
When the enzyme angiotensin I is converted to angiotensin II, the result is potent vasoconstriction and stimulation of aldosterone
Result of vasoconstriction: increased systemic vascular resistance and increased afterload
Therefore, increased BP

22. Antihypertensive Agents: Mechanism of Action
ACE Inhibitors
Aldosterone stimulates water and sodium resorption.
Result: increased blood volume, increased preload, and increased B

23. Antihypertensive Agents: Mechanism of Action
ACE Inhibitors
ACE Inhibitors block the angiotensin-converting enzyme, thus preventing the formation of angiotensin II.
Also prevent the breakdown of the vasodilating substance, bradykinin
Result: decreased systemic vascular resistance (afterload), vasodilation, and therefore, decreased blood pressure

24. Antihypertensive Agents
ACE Inhibitors
captopril (Capoten)
Short half-life, must be dosed more frequently than others
enalapril (Vasotec)
The only ACE inhibitor available in oral and parenteral forms
lisinopril (Prinivil and Zestril) and quinapril (Accupril)
Newer agents, long half-lives, once-a-day dosing
Several other agents available

25. Antihypertensive Agents: Therapeutic Uses
ACE Inhibitors
Hypertension
CHF (either alone or in combination with diuretics or other agents)
Slows progression of left ventricular hypertrophy after an MI
Renal protective effects in patients with diabetes
Drugs of choice in hypertensive patients with CHF

26. Antihypertensive Agents: Side Effects
ACE Inhibitors
Fatigue Dizziness
Headache Mood changes
Impaired taste
Dry, nonproductive cough, reverses when therapy is stopped
NOTE: first-dose hypotensive effect may occur!!

27. Antihypertensive Agents: Categories
Angiotensin II Receptor Blockers (A II Blockers or ARBs)
Newer class
Well-tolerated
Do not cause coughing

28. Antihypertensive Agents: Mechanism of Action
Angiotensin II Receptor Blockers
Allow angiotensin I to be converted to angiotensin II, but block the receptors that receive angiotensin II
Block vasoconstriction and release of aldosterone

29. Antihypertensive Agents:
Angiotensin II Receptor Blockers
losartan (Cozaar)
eposartan (Teveten)
valsartan (Diovan)
irbesartan (Avapro)
candesartan (Atacand)
telmisartan (Micardis)

30. Antihypertensive Agents: Therapeutic Uses
Angiotensin II Receptor Blockers
Hypertension
Adjunctive agents for the treatment of CHF
May be used alone or with other agents such as diuretics

31. Antihypertensive Agents: Side Effects
Angiotensin II Receptor Blockers
Upper respiratory infections
Headache
May cause occasional dizziness, inability to sleep, diarrhea, dyspnea, heartburn, nasal congestion, back pain, fatigue

32. Antihypertensive Agents: Categories
Calcium Channel Blockers
Benzothiazepines
Dihydropyridines
Phenylalkylamines

33. Antihypertensive Agents: Mechanism of Action
Calcium Channel Blockers
Cause smooth muscle relaxation by blocking the binding of calcium to its receptors, preventing muscle contraction
This causes decreased peripheral smooth muscle tone, decreased systemic vascular resistance
Result: decreased blood pressure

34. Antihypertensive Agents
Calcium Channel Blockers
Benzothiazepines:
diltiazem (Cardizem, Dilacor)
Phenylalkamines:
verapamil (Calan, Isoptin)
Dihydropyridines:
amlodipine (Norvasc), bepridil (Vascor), nicardipine (Cardene)
nifedipine (Procardia), nimodipine (Nimotop)

35. Antihypertensive Agents: Therapeutic Uses
Calcium Channel Blockers
Angina
Hypertension
Dysrhythmias
Migraine headaches

36. Antihypertensive Agents: Side Effects
Calcium Channel Blockers
Cardiovascular
hypotension, palpitations, tachycardia
Gastrointestinal
constipation, nausea
Other
rash, flushing, peripheral edema, dermatitis

37. Antihypertensive Agents: Diuretics
Decrease the plasma and extracellular fluid volumes
Results: decreased preload decreased cardiac output decreased total peripheral resistance
Overall effect: decreased workload of the heart, and decreased blood pressure

38. Antihypertensive Agents: Mechanism of Action
Vasodilators
Directly relaxes arteriolar smooth muscle
Result: decreased systemic vascular response, decreased afterload, and PERIPHERAL VASODILATION

39. Antihypertensive Agents
Vasodilators
diazoxide (Hyperstat)
hydralazine HCl (Apresoline)
minoxidil (Loniten, Rogaine)
sodium nitroprusside (Nipride, Nitropress)

40. Antihypertensive Agents: Therapeutic Uses
Vasodilators
Treatment of hypertension
May be used in combination with other agents
Sodium nitroprusside and diazoxide IV are reserved for the management of hypertensive emergencies

41. Antihypertensive Agents: Side Effects
Vasodilators
Hydralazine:
dizziness, headache, anxiety, tachycardia, nausea and vomiting, diarrhea, anemia, dyspnea, edema, nasal congestion
Sodium nitroprusside:
bradycardia, hypotension, possible cyanide toxicity

42. Antihypertensive Agents: Nursing Implications
Before beginning therapy, obtain a thorough health history and head-to-toe physical examination.
Assess for contraindications to specific antihypertensive agents.
Assess for conditions that require cautious use of these agents.

43. Antihypertensive Agents: Nursing Implications
Educate patients about the importance of not missing a dose and taking the medications exactly as prescribed.
Patients should never double up on doses if a dose is missed; check with physician for instructions on what to do if a dose is missed.
Monitor BP during therapy. Instruct patients to keep a journal of regular BP checks.

44. Antihypertensive Agents: Nursing Implications
Instruct patients that these drugs should not be stopped abruptly, as this may cause a rebound hypertensive crisis, and perhaps lead to CVA.
Oral forms should be given with meals so that absorption is more gradual and effective.
Administer IV forms with extreme caution and use an IV pump.

45. Antihypertensive Agents: Nursing Implications
Remind patients that medications is only part of therapy. Encourage patients to watch their diet, stress level, weight, and alcohol intake.
Patients should avoid smoking and eating foods high in sodium.
Encourage supervised exercise.

46. Antihypertensive Agents: Nursing Implications
Instruct patients to change positions slowly to avoid syncope from postural hypotension.
Patients should report unusual shortness of breath; difficulty breathing; swelling of the feet, ankles, face, or around the eyes; weight gain or loss; chest pain; palpitations; or excessive fatigue.

47. Antihypertensive Agents: Nursing Implications
Men taking these agents may not be aware that impotence is an expected effect. This may influence compliance with drug therapy.
If patients are experiencing serious side effects, or believe that the dose or medication needs to be changed, they should contact their physician immediately.

48. Antihypertensive Agents: Nursing Implications
Hot tubs, showers, or baths; hot weather; prolonged sitting or standing; physical exercise; and alcohol ingestion may aggravate low blood pressure, leading to fainting and injury. Patients should sit or lie down until symptoms subside.
Patients should not take any other medications, including OTC drugs, without first getting the approval of their physician.

49. Antihypertensive Agents: Nursing Implications
Monitor for side/adverse effects (dizziness, orthostatic hypotension, fatigue) and for toxic effects.
Monitor for therapeutic effects
Blood pressure should be maintained at less than 140/90 mm Hg