Cardiovascular Flashcards
Stage I (SBP 140-159 & DBP 90-99) HTN: med used
- Diuretics: thiazide-type
- May consider angiotensin-converting enzyme (ACEI), angiotensin receptor blocker (ARB), calcium channel blocker (CCB), or combination
Stage II (SBP greater than or equal to 160/ DBP greater than or equal to 100) HTN: meds used
- Two-drug combination: thiazide-type & ACEI, ARB, BB, CCB
Heart Failure Stage A: meds used
ACEI are drug of choice
ARBs are considered but more expensive
Heart Failure Stage B: Meds used
ACEI in all patients, ARBs for those who cannot tolerate ACEI
BB in most
Heart Failure Stage C: Meds Used
ACEI and BBs (nonselective) in all patients
Diuretics, digoxin
Spironolactone
Heart Failure Stage D: Meds Used
Sacubitril/Valsartan (Entresto) in lieu of ACE or ARB
Inotrope: dobutamine
Ventricular assist device, transplantation, hospice
ACE Inhibitors: Pharmacodynamics
Inhibition of angiotensin-converting enzyme (ACE) activity results in decreased production o both angiotensin II and aldosterone
Can lower vascular resistance without decreasing CO or GFR
Does not produce reflex tachycardia
Strong evidence for CV & cerebrovascular risk reduction, HF, & slowing renal disease. Improves oxygenation to heart muscle, decreases inappropriate remodeling of heart muscle after MI or HF, reduces effects of diabetes on kidneys
Improves insulin sensitivity, does not affect glucose metabolism or raise serum lipid levels.
ACE Inhibitor: Clinical Uses
Younger caucasian patients:
- Patients w/ angina: prevent formation of AT II & decreases pulmonary vascular resistance by decreasing retention of NA & water & reduces extracellular fluid & preload
- Patients w/ diabetes: prevents or slows neuropathy
- After MR or HF, for ventricular remodeling
Not as effective in African American patients- when combined with diuretic, race no longer an issue
ACE Inhibitors: ADRs
3-4x greater risk of angioedema in African Americans & Asians
Dry cough (bradykinin-mediated), hypotension, loss of taste, angioedema, blood dyscrasias, teratogenicity, hyperkalemia, acute renal failure, cholestatic jaundice, pancreatitis, rash
ACE Inhibitor: Monitoring and Patient Education
Monitoring:
- Possible orthostasis within 1 hour of admin. when starting & with each dosage change
Patient education:
- Do not double dose if one is missed
- Hypotension most common ADR
- Cough common with older-generation agents
Function of RAAS (Renin-Angiotensin-Aldosterone System)
Regulator of BP and determinant of target-organ damage
It controls fluid and electrolyte balance through coordinating effects on the heart, blood vessels, and kidneys
Angiotensin II Receptor Blockers (ARBs): Pharmacodynamics
Prevent binding of AT II to receptors in kidney, brain, heart, and arterial walls
Inhibit the RAAS and cause fall in peripheral resistance
Evidence supports use in kidney disease until late stage and HF, but not all forms are renal protective like ACEI
No bradykinin-mediated cough like with ACEI
Considered alternatives for patients who cannot tolerate ACE or become resistant
Many combined with HCTZ
ARBs: ADRs, Monitoring, and Patient Education
ADRs:
- Similar to ACEIs but typically no problem with cough
Monitoring:
- Like ACEI, orthostasis with dose changes
Patient Education:
- Do not double dose if one is missed
- Hypotension most common ADR
Direct Renin Inhibitors (DRI)- Alsikiren (Tekturna): Pharmacodynamics
Works on the RAAS
Can be used for HTN, awaiting word on HF; not same MI indication as ACEI or ARB
Does not have the same renal protective properties as ACEI
For example, ACEI must stop when creatinine rises
Same issues in pregnancy, perhaps fewer issues with K+ and cough
Neprilysin Inhibitors (New Drug Class)
Sacubitril/valsartan (Entresto) decreases hospitalizations & death in chronic HF
- Ejection fraction (EF) < 40%
Taken in place of ACE or ARB
Not given with BBs, such as carvedilol
Increases renal blood flow & improves diuresis
Require 36-hour washout between ACE/ARB/BB
Sometimes called “game changer medication”
Calcium Channel Blockers (CCBs): Pharmacodynamics
Functionally act as vasodilators, lowering calcium influx into smooth muscles
First choice for African Americans with HTN
- can be used as add-on medications for others
Two classes:
- Type I - Non-dihydropyridines
- Type II - Dihydropyridines
CCB Type I
Non-dihydropyridines
Affect conduction through the atrioventricular (AV) node and have negative chronotropic effects
- Used in treating supraventricular tachycardia
- Diltiazem (cardizem), verapamil (Calan)
CCB Type II
Dihydropyridines
Do not affect conduction through the AV node
- Nifedipine (procardia), amlodipine (Norvasc), felodipine (Plendil)
CCB: Metabolism, ADRs, Monitoring
Metabolized by the liver, CYP450 3A4
ADRs:
- very constipating and can cause dizziness, HA, edema, rash, and gingival hyperplasia
Monitoring:
- Verapamil has strongest negative inotropic effect and should be avoided in patients with HF
- CCB/ACE combination decreases peripheral edema by 50% vs high-dose CCB alone
CCBs: Patient Education
Pregnancy Category C
Avoid NSAIDs, alcohol, being in a jacuzzi alone
GERD symptoms get worse because of decrease esophageal tone
Cardiac Glycosides: dose
Serum concentrations greater than 1 mg/mL increase mortality
- Initiate therapy at the lowest dose possible
Cardiac Glycosides- Digoxin: pharmacodynamics
Highly selective inhibitor of adenosine triphosphatase (ATPase) system
- Inhibition of this pump results in sodium & calcium buildup inside the cell, which leads to increased contractility of heart muscle
New research shows it may increase mortality in women
Cardiac Glycosides- Digoxin: Use, Half-Life, Drug Interaction
Benefits are best in patients with severe HF, enlarged heart, & third heart sounds, & in patients who do not respond to ACEI & BBs
Well absorbed orally
Not extensively metabolized, excreted unchanged by kidneys
Half-life is 36-48 hours
- In the absence of oral or IV loading, steady state is achieved in four half-lives or 1 week
- Reduced clearance of digoxin with drug interaction- Quinidine, amiodarone, verapamil, diltiazem
Cardiac Glycosides- Digoxin: ADRs
GI most common: anorexia, N/V, diarrhea
CNS: fatigue, disorientation, depressio, hallucinations, visual disturbances (yellow vision & green halos around lights)
Toxicity: atrial arrhythmias/tachycardia in children
Cardiac: bradycardia, PVCs, junctional & atrioventricular (AV) block arrhythmias, & bigeminy
Avoid using in patients with normal left ventricular systolic function
Cardiac Glycoside- Digoxin: Monitoring and Patient Education
Monitoring:
- Diagnosis of toxicity is based on both clinical & lab data
- Toxicity commonly occurs with serum levels greater than 2 mg/mL
- Monitor Potassium levels (it can cause high potassium)
Patient Education:
- Take at same time each day
- Do not double dose
- Monitor for signs of toxicity
- Take pulse, hold for HR less than 60 or greater than 100 bpm
Absolute Refractory Period
Regardless of the strength of a stimulus, the cell cannot be depolarized