Anti-Hypertensives part 2 Flashcards
What are the first choice agent for hypertension and congestive heart failure and the most commonly prescribed diuretic?
Thiazides
Describe the 2 main action and location of action of Thiazides
- Inhibition of active Na+ reabsorption in the proximal and distal tubules
- Inhibition of carbonic anhydrase = decreased availability for H+ exchange with Na+
What are the desired effects or outcomes of Thiazide diuretics?
- Lower BP
- Decreased cardiac output
- Decreased peripheral resistance
- Normalization of cardiac output after several days
Thiazide diuretics lower BP by lowering what specific fluid volumes?
- Decrease plasma volume
2. Decrease extracellular fluid
What cardiac principle explains a decreased cardiac output by Thiazide diuretics?
Starling’s Law = if decrease amount of blood returning to the heart (preload), heart doesn’t have to work as hard to eject blood back into the systemic circulation
Name the main brand name and generic name drug that is classified as a thiazide diuretic?
○ HCTZ (Microzide)
- Hydrochlorothiazide
3 uses of HCTZ
- Hypertension
- Edema from congestive heart failure
- Nephrotic syndrome
A patient presents in your office with hypertension and is currently taking microzide. What oral complications might you suspect?
- Xerostomia
- Lichenoid drug reaction
- Photosensitivity
If a patient is on a thiazide diuretic, what adverse effects may occur at a physiological level?
○ As Na+ accumulates in distal proximal tubule, more K+ is lost. This may result in hypokalemia.
○ Hypokalemia has toxic effects in heart and muscles
○ **If sodium intake increases, potassium loss is exacerbated
Name the 10 adverse effects of Thiazide Diuretics
- Hypokalemia
- Loss of carbonate (HCO3-)
- Hypomagnesaemia
- Hyponatremia
- Hyperuricemia
- Hyperglycemia
- Elevated cholesterol
- Elevated triglycerides
- Weakness/fatigue
- Sexual dysfunction
What type of hypertensive patients would not be considered good candidates for a Thiazide diuretic?
- Diabetic patients (Increased glucose)
- High cholesterol or lipids
What are the two preparations of thiazide drugs?
- Hydrochlorothiazide
- Chlorothiazide
What is the diuretic of choice for serious edema?
- Loop diuretic
- Cause a major loss of volume
Name the indications that would warrant a prescription of a loop diuretic?
- Acute HTN
- Pulmonary edema
- Congestive heart failure
Method of action for a loop diuretic
- Potent inhibition of active Na+ reabsorption in the ascending loop of henle by blocking reabsorption of Cl-
- Inhibits the Na+ K+ Cl- symporter
Why are loop diuretics considered toxic?
- They can be toxic due to such rapid loss of electrolytes
What does it mean that all loop diuretics are ototoxic to some degree?
- They cause hearing loss/deafness
Name the classic example of a loop diuretic
- Lasix
Generic: furosemide
Use of Lasix
- HTN
- Edema from congestive heart failure
- Hepatic/renal disease
If a patient presents in your office and is taking Lasix, what oral complications might you suspect?
- Vomiting
- Oral irritation
- Xerostomia
- Lichenoid drug reaction
Adverse effects of loop diuretics
- Hyponatremia
- Hypokalemia (risk for arrhythmias)
- Hyperglycemia
- Hypocalcemia (heart toxicity from Ca+ loss)
- Hyperuricemia
- Nephrotoxicity (inc. risk if used with Keflex)
- Ototoxicity
- GI distress
- CNS effects
Name the common loop diuretics
- ethacrynic acid (Edecrin)
- furosemide (Lasix)
- bumetanide (Bumex)
- torsemide (Demadex)
What is the cellular mode of action for Potassium-sparing diuretics?
○ Competes with aldosterone for receptor sites in the distal renal tubules
○ This increases Na+, Cl- and water excretion while conserving K+ and H+
○ **More simply stated:
- Blocks affect of aldosterone
- Prevents usual loss of K+
Name the preparations of Potassium-sparing diuretics
- Spironolactone (Aldactone)
- Triamterene (Dyrenium)
- Eplerenone (Inspra)
Potassium-Sparing diuretics are commonly used together with what other diuretic?
Thiazides
Helps prevent thiazide induced hypokalemia
Adverse effects of Potassium- sparing diurects
- Hyperkalemia
- Gynecomastia
- Tenderness of breasts in young women
- Menstrual irregularities
- Decreased libido in males
Cellular mode of action for Carbonic Anhydrase Inhibitors
- Inhibits carbonic anhydrase
- Exchange of H+ is decreased and more Na+ is excreted with an accompanying volume of water.
Renal target of action for a carbonic anhydrase inhibitor?
- Proximal convoluted tubule
- Distal convoluted tubule