Diuretics and antihypertensives (2 hrs Pharma) Flashcards
What percent of Na is reabsorbed at each segment of the nephron?
- Proximal Tubule- 70%
- Loop of Henle- 25%
- DCT/CD- 4.5%
Where do Acetazolamide and mannitol act on the nephron?
PCT
Mannitol draws free water out of the tissue and into circulation.
Acetazolamide used to treat altitude sickness because it eliminates HCO3- in the blood.
What do loop diuretics (such as furosemide aka Lasix) inhibit?
Na+ K+, Cl- cotransport in ascending loop.
True or False: loop diuretics are the first line of defense for hypertension.
False:
thiazides are the first line of defense.
What is the difference between Furosemide (Lasix), Ethacrynic Acid, and Torsemide?
- Furosemide (La SIX)
- most commonly use loop. Dosed every SIX hours.
- Ethacrynic Acid
- only non-sulfa containing loop or thiazide
- Torsemide
- improved bioavailability with data in heart failure
What do thiazide diuretics inhibit?
Na/Cl cotransporter in distal tubule. Used for BP control. May cause gout attacks in dehydrated patients. May also increase Ca++
Which thiazide may increase Na excretion even in patients with Kidney disease or impaired GFR?
METOLAZONE + Loop Diuretic
Where do Potassium Sparing Diuretics have their action? Why are the frequently used with other diuretics?
Collecting Duct. Often used to combat hypokalemia caused by other diuretics.
How does spironolactone work?
It inhibits aldosterone receptors. Spironolactone may cause gynecomastia. Eplerenone avoids this side effect.
What determines BP? FYI we left diuretics and are now talking about Hypertensive meds.
CO and Vascular Resistance.
What does ACEI inhibit? How are ARBs different?
Conversion of Angiotensin 1–>Ang2.
ARBS block the receptor.
All ACEI end in…
-pril
What effect does Ang II have on the golmerulus
Constrict Efferent Arteriole. This is one reason why ACEI are helpful.
Which type of Calcium Channel Blocker (CCB) has effect on BOTH vasodilation and cardiac conduction?
Non-Dihydropyridines: (Verapamil and Diltiazem) Anything ending with -dipine is strictly vasodilatory.
What causes edema with use of CCBs?
Vasodilation. Therefore Diuretics DO NOT HELP with this because it is not a salt problem.
Which type of CCB is a inhibitor of CP450?
NonDHPs
With the Beta Blockers Labetalol and carvediol, metoprolol, and atenolol, what are some important differences?
Labetalol and carvedilol (alpha and beta blocker) provides extra antihypertensive effect Metoprolol – renal and hepatic elimination Atenolol – renal elimination
Hydralazine and minoxidil are calssified as….
Vasodilators. They are NOT first line therapies for HTN.
Alpha blockers end in…
-osin
How do Alpha 2 receptor agonists work?
Stimulate CENTRAL presynaptic Alpha 2 receptor to decrease sympathetic tone.
Example Clonidine and methyldopa
How do you distinguish between a HTN urgency and HTN emergency?
Urgency- Severe BP w/o progressive target organ damge. Emergency- 180/120 + impending or progressive organ dysfunction.
What is Sodium Nitroprusside used for?
HTN emergency. It is must be used quickly and has an effect in 1-2 minutes.
Which 2 CCBs are used for HTN emergency?
Clevidipine- ultra fast half life (1-2 min). Don’t worry about hepatic or renal metabolism.
Nicardipine- may cross blood brain barrier and help decrease intracranial pressure.
Which drugs are Selective Beta 1 blockers?
Atenolol, Metoprolol
Which drigs is/arenon-selective Beta 1 and 2 blockers?
Propanolol
Which drugs block both Beta and Alpha receptors?
Carvediol and Labetolol.
