1. Diuretics and Antihypertensives
Chapter 20
Diuretics and Antihypertensives

2. Diuretics and Antihypertensives p482
Diuretics used to treat edema, ascites, HTN
Remove sodium and water from circulation
Antihypertensives: lower blood pressure
Both diuretics and antihypertensives
Used to treat hypertension (HTN)

3. Classifications of diuretics p483
Thiazide diuretics
Loop diuretics
Potassium-sparing diuretics
Osmotic diuretics
Carbonic anhydrase inhibitors
Combination potassium-sparing and hydrochlorothiazide diuretics

4. Thiazide Diuretics p483 Primary site of action
Renal distal convoluted tubule
Prevents sodium and chloride reabsorption into circulation
Prototype: hydrochlorothiazide (HCTZ)

5. Thiazide Diuretics: Side Effects p483
Loss of potassium
Loss of sodium and chloride
Hyperglycemia: high blood sugar
Hyperuricemia: high uric acid
Skin rash

6. Thiazide Diuretics p483 Safe Require supplements Potassium chloride
Administered as tablets, capsules, IV, liquids, and effervescent solutions
Teaching
Encourage the client to eat oranges, apricots, and bananas for K+ in diet
Signs/symptoms of hypokalemia, hyponatremia
Take diuretics in the morning for once a day dose. If twice a day dose, take second dose no later than 6pm.

7. Loop Diuretics p485 Prototype: furosemide (Lasix)
Works directly on the ascending limb of the loop of Henle
Inhibits sodium and chloride reabsorption
More potent than thiazides
Remain effective even in pt with seriously impaired glomerular filtration rates

8. Loop Diuretics: Side Effects p485
Dry mouth
Hypokalemia
Hearing loss
Fatigue
Dehydration
Hypotension

9. Symptoms of hypokalemia p504
Pulse irregularities, irregular HR
Leg cramps
General muscle weakness

10. Symptoms of hyponatremia p503
Weakness
Confusion
Abdominal cramps
Muscle twitching
If severe, seizures may occur

11. Potassium-Sparing Diuretics p485
Inhibit action of aldosterone (produced by adrenal cortex) or block Na+ reabsorption in distal tubule
Example: spironolactone, triamterene
Conserve potassium
Pt teaching: do not eat diet high in K+

12. Osmotic Diuretics p485
Action: Produce a profound diuretic effect by a high concentration of osmotic agent in the kidney tubule.
Used to treat increased intracranial pressure and acute renal failure
Example
Mannitol

13. Carbonic Anhydrase Inhibitors p485
Examples:
acetazolamide
methazolamide
Very weak diuretic effect
Treats glaucoma: reduces the rate of production of aqueous humor in the eye

14. Combination Potassium-Sparing and Hydrochlorothiazide Diuretics p 485
Decreases adverse effects of each of the diuretic components
Decreases hypokalemia from thiazides
Decreases hyperkalemia from potassium-sparing diuretics
Examples:
Aldactazide
HCTZ and spironolactone
Dyazide
HCTZ and triamterene

15. Hypertension p488
An abnormal increase in arterial blood pressure

16. Blood Pressure p488 Blood pressure factors: Normal blood pressure
CO = cardiac output
PR = peripheral resistance
Normal blood pressure
Systolic < 120 mm Hg
Diastolic < 80 mm Hg

17. Treatment for hypertension (HTN) p489
Stepped care approach based on cardiovascular risk factors (box 20-1, 20-2, 20-3)
Lifestyle modification is always the first step in treating hypertension
Weight reduction
Exercise program
Smoking cessation
Reduction of sodium in diet
Moderation of alcohol intake

18. Stepped care approach cont p489-490
If lifestyle modifications do not achieve sufficient reduction in BP, then drug therapy is initiated.
Oral diuretics often first drug prescribed

19. Central-Acting Antiadrenergics p490
Potent antihypertensives.
Sympathetic outflow from the central nervous system is decreased
Epinephrine and norepinephrine is decreased
Adverse effect
Sedation
Example: clonidine, methyldopa
Short acting, must take multiple doses per day

20. Central-Acting Antiadrenergics p490
General side effect
High incidence of orthostatic hypotension
Instruct clients to change positions slowly
Sedation
Instruct clients
Do not stop meds abruptly
Rebound hypertensive crisis
Oral forms should be given with meals so that absorption is more gradual and effective.

21. Peripherally Acting Antiadrenergic Agents p491
Two main actions
Deplete norepinephrine
Adverse effect: depression
Block adrenergic receptors: Prevent sympathetic nervous system stimulation
Adverse effect: hypotension
First dose effect: development of significant hypotension and syncope with sudden loss of consciousness with the first few doses or if dosage is increased rapidly
Examples:
prazosin
terazosin
doxazosin

22. Beta-adrenergic Blocking Agents “Beta blockers” p491
Inhibit beta1 and beta2 receptors in the heart and the lungs
Best blood pressure lowering result is achieved when given with a diuretic agent
Negative inotropic
Negative chronotropic
Negative dromotropic
Prototype: propranolol (Inderal)
Adverse effect: bronchoconstriction
Hold dose if HR less than 50

23. Miscellaneous vasodilators p492
Vasodilators directly dilate the peripheral arterioles
Hydralazine: dilates peripheral arterioles
Side effects: palpitations, tachycardia
Minoxidil: dilates peripheral arterioles
Side effect: growth and thickening of fine body hair
Rogaine is minoxidil in topical dosage form marketed as treatment for male pattern alopecia

24. Angiotensin-converting enzyme inhibitors p492
Called ACE inhibitors (-pril)
Action: antagonists to the renin angiotensin-aldosterone system
ACE inhibitors prevent:
Angiotensin I conversion to angiotensin II
Prototype: Lisinopril

25. ACE Inhibitors: Side Effects p492
Fatigue
Dizziness
Headache
Mood changes
Impaired taste
Dry, nonproductive cough
Persistent cough could be indication to withdraw Lisinopril
Loss of ability to ejaculate, erectile dysfunction

26. Angiotensin II Antagonists p492
Allow angiotensin I to be converted to angiotensin II, but block the receptors that receive angiotensin II
Block vasoconstriction and release of aldosterone
Well-tolerated
Coughing not a concern
Examples
irbesartan
losartan
valsartan

27. Calcium Channel Blockers p493
Prevent calcium from entering muscle cell thereby reducing muscle contraction
Relax peripheral arterioles and reduce peripheral resistance
Prototype: verapamil (Calan)
Side effects
Hypotension
palpitations
Tachycardia
peripheral edema

28. Hypertensive emergencies p494,500
Diastolic pressure exceeding 120 mm Hg with evidence of end organ damage.
Agents for treating hypertensive emergencies: diazoxide nitroprusside sodium

29. Sodium restriction in diet p502-503
Nurses teach label reading
Signs of hyponatremia:
weakness
confusion
abdominal cramps
muscle twitching
If severe, seizures may occur.

30. Limiting adverse effects of antihypertensive meds p505
Non-compliance with medication schedule has many causes
Do not discontinue the med, but inform health care provider of the side effects so alterations can be made.

31. Patient teaching Teach pt to take BP daily and keep log
Teach at least one family member to take pt BP
Smoking cessation
Teach signs and symptoms of sodium or potassium depletion
Avoid activities that place stress on cardiovascular system.
Avoid straining to pass stool
Avoid heavy meals
Teach lifestyle modifications