Exam 4 Adjuncts Flashcards
Beta receptors activate ____ to produce ___?
Adenylyl cyclase & cAMP
Chronic use of beta antagonists leads to?
Upregulation of receptors
Besides decreasing CO, beta antagonists also ____?
Inhibit renin release
Which phase of the cardiac cycle do beta blockers affect?
Phase 4, decrease the in slope
What medication would be given for thyrotoxicosis?
Beta antagonist
Under the SCIP, who receives a beta blocker & when would they not?
- Pt’s at risk for MI & already on beta blocker.
- Do not give if HR <60
75% of beta receptors are ___ & located in ___?
B1 & myocardium
Which beta blocker is not cardiac selective?
Propranolol
Which B1 antagonist is cleared via plasma hydrolysis?
Esmolol
Metoprolol is cleared via___ & atenolol is cleared via___?
- Hepatic
- renal
Which beta blocker has the longest E1/2 & what is it?
Atenolol & 6-7hrs
Which beta blocker has the smallest volume of distribution?
-Propranolol.
- It has high protein binding.
What are the IVP doses for Metoprolol, Atenolol & Esmolol?
- Metoprolol: 1 mg q5min for 5mg total (repeat PRN)
- Atenolol: 5-10 mg q 10min
- Esmolol: 10-80 mg
How does Inderal affect opioids & LA’s?
It decreases their clearances
What lasts longer with Inderal, negative inotropy or negative chronotropy?
Negative chronotropy
What is the most selective B1 blocker?
Atenolol
What is the onset & offset of Esmolol?
5mins & 30mins
What meds can lead to negative side effects with Esmolol, or other beta blockers & what are they?
Cocaine & epinephrine. Can lead to pulmonary edema & CV collapse
What secondary messenger is synthesized with alpha-1 agonists?
IP3
Alpha-1 agonists determine what 3 things?
- Arteriolar resistance
- venous capacity
- BP
Alpha-2 agonists do what with norepinephrine?
Decrease presynaptic NE release in the brain stem
Where does phenylephrine have its affects?
- Venous constriction
- Indirectly releasees NE
Increased amounts of Neo could lead to?
Reflex bradycardia
Labetalol has what kind of ratio?
7:1 beta to alpha blocking
What receptors are affected by Labetalol?
- Selective alpha-1
- Beta-1 & 2
What is the IVP dose for Labetalol?
2.5 - 5 mg
What can possibly increase the time for a Pt to come off bypass?
Prolonged beta-1 blockage
What receptors & how (+/-) does dobutamine affect?
- Alpha-1 & 2 (+)
- beta-1 (++++)
- beta-2 (++)
Sympathomimetics lacking Beta-1 specificity may lead to?
Reflex-mediated bradycardia
What are the direct acting sympathomimetics?
Epi, NE, phenylephrine, dopamine
What are the indirect-acting sympathomimetics?
Ephedrine & Neo just a bit
Which sympathomimetic has the highest alpha selectivity?
Phenylephrine
Which sympathomimetic results in the highest CO?
Epinephrine
Which sympathomimetic results in the highest PVR increase?
Neo
What affects does vasopressin have on CO, HR & PVR?
- Increases CO & PVR.
- No effect on HR
What is a downside to ephedrine?
Increased tachyphylaxis
What is the preferred sympathomimetic in pregnancy & why?
- Ephedrine
- Does not affect uterine blood flow
How does vasopressin assert its affects?
Causes arterial vasoconstriction
What two hypotension examples is vasopressin ideal for?
- Catecholamine-resistant hypotension
- ACEi resistant hypotension
What are the side effects of vasopressin?
- Coronary artery constriction
- Abd pain, N/V
- decreased Plt count
What secondary messenger is released from nitric oxide?
cGMP inhibits calcium entry into smooth muscle
How do nitro-vasodilators assert their effects?
Decreasing SVR & venous return
What kind of vasodilator would be beneficial in someone with pulmonary congestion?
Nitroglycerin or nitroprusside
What is the infusion dose for nitroprusside?
- 0.3 mcg/kg/min
- up to 2 mcg/kg/min
Where does nitroprusside work?
Mostly arterial smooth muscle but also venous smooth muscle
What are some signs of cyanide toxicity?
- Increased SvO2
- metabolic acidosis
- CNS dysfunction/LOC changes
Where does nitroglycerin act on?
Venous capacitance vessels & large coronary arteries
What are 4 indications for nitroglycerin use?
- Acute MI
- controlled HTN
- sphincter of Oddi spasm
- retained placenta
What is the onset, ½ life & initial IV dose for hydralazine?
- Onset 1hr
- ½ life: 3-7hrs
- dose 2.5 mg IV
Which CCB type is selective for arteriolar beds?
Dihydropyrimidines
What are the effects of CCB’s?
- Decrease SVR & systemic BP
- increase coronary blood flow
- decrease dromotropy thru AV node
Which 2 CCB’s could potentially increase the HR?
Nifedipine & Nicadipine
Which CCB causes the least myocardial depression?
Nicardipine
What CCB causes the most SA node depression?
Verapamil
Which CCB has marked AV node depression?
Verapamil
Which CCB causes the highest degree of coronary artery dilation?
Nicardipine
Which 2 CCB cause marked peripheral artery dilation?
Nifedipine & Nicardipine
Which vasodilator can worsen someone’s PaO2?
Nitroprusside
Which type of beta blocker is best suited for COPD patients?
Beta-1 selective to prevent bronchospams & ventilatory depression
Which type of beta blocker is preferred in diabetics?
Beta-1, this way it does not interfere with glycogenolysis
