RAAS Misc
RAAS is an acronym that stands for this four word phrase
Renin-Angiotensin-Aldosterone System
The generic names for all the drugs in this class tend to end in this four-letter suffix (i.e. at the END of each name)?
-PRIL
(e.g. captopril, lisinopril, etc)
The generic name for all the drugs in this ARB class end in the same six letter suffix
-SARTAN
(e.g. losartan, valsartan, etc.)
What is the mechanism of action common to amlodipine, diltiazem, and verapamil?
All are CALCIUM CHANNEL BLOCKERS:
They block calcium channels in smooth vascular smooth muscle, dilating coronary arteries to increase coronary perfusion (i.e. increasing blood flow to the heart), AND dilating systemic arterioles throughout the body to lower blood pressure.
This is the name for the prototype drug introduced this week in this class of drugs called Direct-Acting Vasodilators
hydralazine (APRESOLINE)
This class of drugs blocks Angiotensin II receptors, thereby stopping arteriole and venous dilations, and also blocking aldosterone release
ARBs
(Angiotensin Receptor Blockers)
Part of the Patient Teaching for this class of drugs is that those taking ACE-Is should limit the intake of salt-substitutes and foods high in THIS
(remember the picture of BANANAS on lecture slides)
Are ARBs safe for use by people who are pregnant, yes or no?
NO
Like with ACE-Inhibitors, ARBs are counterindicated in pregnancy due to risk for fetal harm
(in other words, both of these classes of drugs are teratogenic)
Part of patient teaching for those who are taking Calcium Channel Blockers is that they should avoid drinking this specific type of fruit juice because drinking it would increase the risk for drug toxicity
GRAPEFRUIT JUICE
(because this juice inhibits the First Pass metabolism of these drugs, leaving higher drug levels available in the system for longer)
TRUE OR FALSE: Patients who take hydralazine (Apresoline) should be counseled to get up slowly due to the increased fall risk they may experience due to the risk for orthostatic hypotension
TRUE
(especially for geriatric patients, and this should be part of the patient teaching for ALL meds given to treat HTN)
This class of drugs stops the RAAS process by blocking the conversion of Angiotensin I into Angiotensin II
ACE-Inhibitors
(Angiotensin-Converting Enzyme Inhibitors)
This is one potential Adverse Effect of all the ACE-Inhibitor drugs, occurring in approximately 10% of the patients who begin taking it, which if it begins to appear usually indicates that the pt should STOP taking this class of meds and switch instead to an ARB
BONUS POINTS: Name one or more types of patients who may be at higher risk for this adverse effect
COUGH
(Higher risk: patients of advanced age, assigned female at birth, and/or of Asian ethnicity)
TRUE OR FALSE: ARBs block the receptors that bind with Angiotensin II, PREVENTING Angiotensin II from remodeling cardiac structure in a way that would otherwise be harmful to patients
TRUE
(Note: ACE-Inhibitors also prevent cardiac remodeling, but do so by stopping the very formation of Angiotensin II in the first place rather than blocking receptor sites)
Name one major adverse effect of amlodipine (Norvasc) that is not seen in the other CCBs like diltiazem and verapamil
REFLEX TACHYCARDIA
(i.e. elevated HR, because this drug has no suppressant effects on HR, and therefore baroreceptors in the aorta and elsewhere cause the heart to pump faster in an effort to compensate for a drop in BP caused by this drug)
How does hydralazine (Apresoline) work to lower BP (in other words, what is its "mechanism of action")?
Provides SELECT DILATION OF ARTERIOLES to decrease systemic vascular resistance (in other words, decreased "afterload"), which means there is less pressure that the heart has to push against in order to pump out blood
The major result of Aldosterone release from the adrenal cortex
Holds on to and therefore raises blood levels of both Na+ (sodium) and H2O (water), ultimately raising the body's Blood Volume and thus also its Blood Pressure
Note: Most of the drugs in this week's unit stop this process from happening somewhere along the line with the goal of reducing a patient's BP
Name AT LEAST FIVE USES for captopril (Capoten) and the other ACE-Inhibitors in this class (hint: one of them is to treat Hypertension!)
Treatment for HTN, treatment for Heart Failure (HF);
Prevent MI, Prevent Stroke, lower the risk for death in high-risk CardioVascular patients, decrease Nephropathy in patients with DM;
prevent and/or reverse structural changes in the heart that are caused by HTN
Rarely, both ACE-Inhibitors and ARBs can cause this life-threatening Adverse Effect, and if there are signs that a patient is developing this condition the drug should NEVER be given to that patient ever again
ANGIOEDEMA
(swollen tongue, swollen face, swollen glottis: causing difficulty breathing and potentially death)
Which of the three Calcium Channel Blockers introduced in this unit is preferred for use in patients with a Heart Block (slow AV node conduction of electrical signals in the heart), with Bradycardia (low HR), or Heart Failure (low ejection fraction of blood out of the heart with each heart beat)? Why?
amlodipine (NORVASC)
Because this CCB has no suppressant effects on AV node conduction, HR, or heart contractility (which is a key part of ejection fraction), whereas both diltiazem (Cardizem) and verapamil (Calan) slow AV node conduction, slow HR, and decrease the force of ventricular contraction.
HYPERTENSIVE CRISIS
(a severe and rapid spike in BP over 180/120)
After Angiotensin Converting Enzymes (ACE) convert Angiotensin I into Angiotensin II, that active product finds its way to Angiotensin Receptors that are present where?
In the ARTERIOLES (and also to a lesser extent in the VEINS) where it causes constriction;
In the KIDNEYS where it causes renal vasoconstriction that decreases renal bloodflow, as well as the Adrenal Glands of the kidneys where it causes the release of Aldosterone
All of the above ultimately is aimed at raising blood volume in the body. Many of the drugs this week work to BLOCK this process at one point or another with the goal of lowering blood volume-> decreasing BP
Name BOTH of the HOLD parameters for ACE-Inhibitors such as captopril (Capoten), and explain the reason that this drug may sometimes cause each condition
HOLD IF POTASSIUM (K+) is greater than 5.0
because by blocking the process that releases
aldosterone, more Na+ goes out of the body
and more K+ stays in the body, sometimes
leading to overly elevated potassium (hyperkalemia)
HOLD IF Systolic Blood Pressure (SBP)<100
because this drug will drop the BP, and we do not
want SBP to fall into dangerously low hypotension
Another name for Angiotensin II (whose receptor sites are blocked by ARBs) is "Kinase II," an enzyme that breaks up and inactivates Bradykinin. Since UNLIKE ACE-Inhibitors, ARBs DO allow Angiotensin II/Kinase II to circulate in the blood, this means that patients on ARBs typically do not experience this adverse reaction that is fairly common for patients on "-prils" due to the elevated levels of Bradykinin caused by ACE-Inhibitors.
COUGH
Part of the patient teaching common to patients on all Calcium Channel Blockers is that they need to be sure to practice good dental hygiene in order to prevent THIS medical condition
GINGIVAL HYPERPLASIA
Included in the Patient Teaching for hydralazine (Apresoline) is that the patient needs to notify their provider if they experience WHAT signs/symptoms (list AT LEAST FOUR)
HR>100
heart is "RACING"
Systolic Blood Pressure < 100
HEADACHE
DIZZINESS
WEAKNESS
FATIGUE