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61 terms

Pharm: Cardio Rx's

Rxs that enhance elimination of water (& salt) by kidneys
Five groups of Diuretics
Carbonic Anhydrase inhibitors
Osmotic diuretics
Loop diuretics
Potassium-sparing diuretics
Carbonic anhydrase inhibitor location, mechanism & eg
AT PCT; When enzyme is inhibited, [HCO3] increases--> alkaline urine--> diuresis;
Acetazolamide (Diamox)
Loop diuretics location, mechanism & eg
MOST EFFECTIVE gp, so used most often.
Ascending Limb; Active transport at PCT forces Rx into Loop. Here, a Na/K/2Cl (NKCC2) transporter is blocked, so Na & K are not reabsorbed -- > H2O retained;
Furosemide (Lasix) [lasso loop!]
Loop diuretic strength & weakness
Strength: BEST at WATER removal;
Weakness: POOR at lowering BP
Loop diuretics competitor & SEs
Uric acid competition-> hyperuremia;
HYPOs: volemia, natremia, kalemia, calcemia;
HYPERs: uricemia (GOUT), glycemia;
Rx Iax: Sulfonamides (<5% cross reactive)
Thiazide diuretics location, mechanism & eg
DCT; Often used as SYNERGIST w/ Loops Block Na/Cl cotransport (NCCT), so Na is not reabsorbed -->H2O retained;
Hydrochlorothiazide, Chlorthalidone, & Metolazone ("thiazide-like")
Class of Diuretics listed as 1st line in JNC VII
Thioazides (Hydrochlorothiazide, Chlorothalidone)
Diuretics that take up to 6 wks to hit effective conc.
POS SEs of thiazide diuretics
Increased Ca reabsorption --> Osteoporosis Tx;
Decreased peripheral vasc resistance--> edema Tx
SEs of thiazides
HYPOs: volemia, natremia, kalemia (arrhythmia)
HYPERs: CALCEMIA, uricemia (GOUT), glycemia;
TOXICITY: small increase in LDL
Diuretic that causes 5-10% Impotence in men
Aldosterone analog K-sparing diuretics (Spironolactone=Aldactone)
Potassium sparing diuretics location, mechanism & eg
DCT/Collecting duct; block a Na pump (ENaC) that is UNCOUPLED from K. Allows DIURESIS WITHOUT K LOSS;
Amiloride (Midamor), & Triamterene (Dyrenium)
Weak diuretics w/ mortality benefits for CLASS II & CLASS IV heart failure pts (RALES) and low ejection frction post MI
Spironolactone & Eplerenone. Belong to K-sparing
Potassium sparing diuretic SEs
Hyperkalemia, Gynecomastia (spironolactone is a steroid), Dysmenorrhea
Estrogen analog diuretics & their larger class
Aldosterone Antagonists: Aldactone & Spironolactone-- belong to K-sparing diuretics
Diuretic class used with Thiazides to protect against potassium loss
Potassium-sparing: Triamterene & Amiloride
ADH inhibitor location mechanism & eg
Block V2 receptors for ADH in the collecting duct. Without ADH, aquaporins can't be inserted & H2O can't exit. Conivaptan (Vaprisol)
Osmotic Diuretics location, mechanism & eg
PCT & Descending limb; Enter @ glomerulus but are not reabsorbed-->increases osmotic pull on H2O; eg: Mannitol(Osmitrol), glycerol
SE Osmotic diuretics
Clinical indications for diuretics
HTN, CHF, Hepatic ascites, Pulmonary edema, RF/nephrotic syn, Hyperaldosteronism (Spironolactone)
Hypercalcemia Tx
Loop diuretics
Hypocalcemia Tx
Thiazides (Hydrochlorothiazide)
Loop diuretic (Furosemide = Lasix) & ADH inhibitor (Conivaptan = Vaprisol)
Intracranial pressure Tx
Glaucoma & Epilepsy Tx
Hyperaldosteronism Tx
Hyperkalemia Tx
Loop diuretic (Furosemide = Lasix)
Hypokalemia Tx
K-Sparing diuretic (Amiloride = Midamor)
Diuretic that may cause Gynecomastia or Dysmenorrhea
Spironolactone (K-sparing steroid)
Diuretics that exacerbate gout
Loops & Thiazides
Act at the ascending limb
Loop diuretics
Act at the descending limb
Osmotic diuretics
Act at the PCT
Carbonic anhydrase inhibitors (Acetazolamide)
Act at the DCT & CT
K-sparing diuretics (Spironolactone & Amiloride) and ADH inhibitors (Conivaptan)
"Gates" blocked by CCBs
Voltage sensitive slow Ca channels
Effect of CCBs
Reduces plateau phase of cardiomyocyte contractions in SA & AV nodes; Vasodilation -> lowered BP
Area of heart not affected (much) by CCBs
Two most common CCBs & their effects, tropic summary
Verapamil & Diltiazem;
DDPRR: Dilate ALL coronary vessels, Dilate peripherial arterioles (NOT venules), Prolong AV conduction time, Reduce myocardial contractility, Reduce heart rate;
NEG inotrope/NEG chronotrope
Dihydropyridines gp, members, & effects
CCBs; Nifedipine (Procardia), Nicaripine (Cardene), Amlodipine (Norvasc); such strong vasodilators that AV conduction is reduced, Heart rate is increased, Contractility is increased; POS inotrope/POS chronotrope
Clinical indicators for CCBs
PSVT (slows both SA & AV);
A-flutter/A-fib (slowing AV reduces ventricular rate);
Angina (coronary arterioles dilate);
HTN, Cerebral vasospasm, Migraine
Constipation, hTN, Exacerbates CHF (esp verapamil!), AV block/brady, Red (flushing)
Indicators for anti-HTN Rx
CHF, CAD, TIA/stroke, MI, HTN
When to initiate anti-HTN
BP >140/90
BP determinants
(Cardiac output) (Peripheral resistance);
CO = (Rate) (SV);
SV = (Contractility) (Preload-Afterload)
Two BP effectors
Baroreceptors & RAAS
Baroreceptor mechanism & effects
Monitor sudden BP drop; stimulate SNS/inhibit PNS
RAAS mechanism & effects
Low BP-> low perfusion->JGA stimulation->Renin->converts Angiotensinogen to Angiotensin I->(lungs/ACE) converts to Angiotensin II-->vasoconstriction & Aldosterone release-->Na reabsorption/K excretion
1st line anti-HTN Rxs
1. Thiazide (Hydrochlorothiazide)
2. Beta Blockers (esp Metoprolol)
3. ACEIs (Captopril or Enalopril)
BB indications; Contraindications
IND: Tachy, PSVT, Exertion Angina, Hyperthyroid crisis, HTN, Glsaucoma, Migraine;
C-IND: Heart block, CHF, Resting Angina, Asthma, DM, Peripheral Vasc Dz
Bronchospasm, h-glycemia, CNS depression, Insomnia/nightmares, Sexual dysfx
Side effects of Aldosterone antagonists
Hyperkalemia, Gynecomastia (Spironolactone), GI upset
The cardiotherapies that alter RAAS
ACEIs, ARBs, ß blockers, Aldosterone inhibitors, Direct Renin Inhibitors
Rx class that ALL CHF pts MUST be on unless there's a documented reason
MOA for ACEI's
Prevents conversion of Angiotensin I to Angiotensin II
ACEI effects
Prevent vasoconstriction; decrease aldosterone- reduce Na & H2O retention
Heart Rx that preserves renal fx in DM pys
ACEI primary SEs & CIx
1. Cough
2. hTN*
3. Angioedema* (Severe Type I immune rxn, may block breathing) in mucus membranes
4. Hyperkalemia**
5. Taste disturbance (sulfurus)
CIx: Pregnancy
ACEI monitoring issues
BP, Hyperkalemia, Renal fx-- and warn of angioedema
ACEI w/ shortest half-life