Adrenergic Drugs Flashcards
What neurotransmitters are catecholamines?
- Dopamine
- Norepinephrine
- Epinephrine
What are drugs that are directly acting adrenergic drugs?
-they are drugs/neurotransmitters that produce responses by interacting with the adrenoreceptors on target cells (alpha or beta)
What are drugs that indirectly acting adrenergic drugs?
-Drugs that cause the release of norepinephrine
What kind of receptors are adrenergic receptors?
-G protein coupled receptors
What adrenergic receptors does Isoproterenol work on?
-B 1, 2, & 3
**only Beta receptors
Does dopamine act on adrenergic receptors?
- Yes, only at high concentrations
- B1 first, then a1
- not B2
What happens as the group on the amine of a catecholamine gets larger?
That catecholamine has a higher affinity for beta receptors and a lower affinity for alpha receptors
Local anesthetics contain epinephrine.
What receptors are the target?
Why include epinephrine?
-alpha 1 receptors
to achieve local vasoconstriction, which keeps the anesthetic locally for a longer duration
What vascular receptors does epinephrine activate at low vs high doses?
Low dose:
-B2 receptors = vasodilation
High dose:
-a1 receptors = vasoconstriction
What is the effect of Isoproterenol on mean arterial pressure? Why?
-decrease slightly
- Because it will stimulate B receptors in heart which will strongly increase cardiac force and rate = slightly increased systolic pressure
- however, lots of vasodilation, causing diastolic pressure to drop a lot, so MAP will drop a bit
A patient upon arrival at Ben Taub emergency room with very high blood pressure 220 / 160. He was treated with clonidine.
Clonidine is an emergency anti-hypertensive.
What is the effect of clonidine (alpha-2 agonist) on release of norepinephrine from
adrenergic nerve terminals?
A. Increase
B. Decrease
B. Decrease
Describe adrenergic presynaptic autoreceptors.
- Mostly a2
- NE release will stimulate post synaptic cell, but also activate a2 autoreceptor, thus decreasing vesicular release
What receptors does norepinephrine work on?
B1 & alphas
**NOT B2
What receptors does epinephrine work on?
All alpha and beta receptors
List Isoproterenol, Norepinephrine, and epinephrine in order of increasing size of their amine group.
Norepinephrine –> Epinephrine –> Isoproterenol
What is the effect of epinephrine on the immune system?
A. Up regulates immune system
B. Down regulates immune system
B. Down regulates immune system
Cardiovascular effects of dopamine are due to:
1) agonist at dopamine receptors
2) releasing more NE from nerve terminals
3) agonist at B1 and a1 receptors (at higher conc.)
What is the cardiovascular effect of low dose dopamine?
Vasodilation in renal, mesenteric, coronary, and cerebral vascular beds
**only acting on D1 receptors
What are the uses of high doses of dopamine?
- preserve renal blood flow
- protect vital organs
- treat cardiogenic shock
- Increased force of heart contraction
**acts on D1, B1, and a1 receptors
Why is it good that moderate doses of dopamine will increase heart contractility much more than heart rate?
-oxygen demand on the heart does not increase significantly
Where is epinephrine made?
Adrenal medulla
Which receptor does Phenylephrine act on? Is it an agonist or antagonist?
a1 agonist
Which receptor does Clonidine act on? Is it an agonist or antagonist?
a2 agonist
Which receptor does Dobutamine act on? Is it an agonist or antagonist?
B1 agonist
Which receptor does albuterol act on? Is it an agonist or antagonist?
B2 agonist
*fast acting
Which receptor does salmeterol act on? Is it an agonist or antagonist?
B2 agonist
*long acting
Which receptor does Ritodrine act on? Is it an agonist or antagonist?
B2 agonist
You have a trauma patient and your goal is to improve blood flow to kidneys with out increasing work load on the heart.
Best drug (via IV drip) will be:
A. Albuterol (b2 agonist) B. Low dose Dopamine (Intropin) C. Epinephrine (Adrenalin) D. Dobutamine (b1 agonist) E. Norepinephrine (Levophed)
B. Low dose Dopamine (Intropin)
When is Phenylephrine used?
- during surgery to raise BP
- Nasal decongestant
(a1 agonist)
When is clonidine used?
- reduces sympathetic outflow from CNS
- emergency antihypertensive, used in emergency only
(a2 agonist)
What is a-methyldopa used for?
- anti-hypertensive in pregnant women
- prodrug
(a2 agonist)
What is priapism and what is its treatment?
- medical condition in which the erect penis does not return to its flaccid state
- inject cavernosum with Phenylephrine (a1 agonist)
When is Dobutamine used?
-cardiogenic and septic shock to increase cardiac output
B1 specific agonist
When is Ritodrine used?
-relaxes uterus, prevents premature deliveries
B2 selective agonist
Which one of the following drugs is used for
Cardiac stress test?
A. Dobutamine B. Low dose dopamine C. Clonidine D. Phenylephrine E. Methamphetamine
A. Dobutamine
What is Ephedrine used for? And what is its MoA?
- nasal decongestant
- raise blood pressure during surgery
-a and B indirect agonist
Priapism is erections lasting for hours.
Pharmacological treatment is:
A. Albuterol B. Clonidine C. Dobutamine D. Phenylephrine E. Amphetamine
D. Phenylephrine
A. Which of the following is a bronchodilator?
B. Which one is a choice antihypertensive in pregnant women?
C. Which of the following raises BP by vasoconstriction?
A. Dobutamine B. Clonidine C. Phenylephrine D. Salmeterol E. Alpha-methyldopa
A= D. Salmeterol
What receptors does dopamine act on at low, moderate, and high doses?
Low: D1
Moderate: D1 & B1
High: D1, B1, & a1
Which receptor does Formoterol act on? Is it an agonist or antagonist?
B2 agonist
*long acting
What is epinephrine’s effect on Mast cells? What receptor?
- inhibits degranulation (think anaphylaxis)
- B2 agonist
What is the first line treatment for Parkinson’s disease?
A. SSRIs B. L-Dopa C. Dopamine blockers D. Serotonin blockers E. Acetylcholinesterase inhibitors F. Methylphenidate (Ritalin)
B. L-Dopa
Why don’t we use selective B2 blockers?
-you will suffocate your patient
What is a Sympathomimetic?
-a drug that mimics nor/epinephrine
What type of side effects do SSRIs have?
-Adrenergic sid1e effects
What are B1 blockers used to treat?
- Hypertension
- CHF
- Post-MI
- Angina pain
- Glaucoma
- migraine, hyperthyroidism, performance anxiety
What is the suffix of all beta blockers?
-olol
Why don’t we stop B blocker use abruptly?
- the # of B receptors will have been upregulated
- stopping immediately can cause arrhythmias
What is Labetalol?
- Used to treat Hypertension
- Mixed alpha 1 and Beta blocker
What is Carvedilol?
- Used to treat Hypertension
- Mixed alpha 1 and Beta blocker
Why is a thiazide sometimes used in conjunction with a B blocker?
- to downregulate the RAAAs system
- Decrease plasma volume
What are cardio-selective B blockers?
- selective to B1
- less bronchoconstriction
- More expensive
How can a partial B agonist treat hypertension?
- competing with full agonist epinephrine for B receptors
- wont activated as much as epinephrine, so net effect is decreased cardiac output
Out of the following receptors, which receptors predominate (abundant) on smooth muscle around veins?
A. Beta 2 B. Alpha 1 C. Alpha 2 D. Beta 1 E. Beta 3
B. Alpha 1
What are alpha (1) blockers used to treat?
- antihypertensive
- treat BPH
**Alpha 2 blockers have little clinical use
Vascular tone (peripheral vascular resistance) is maintained by activation of :
A. Beta-1 receptors B. Nicotinic receptors C. Beta-2 receptors D. Alpha-1 receptors E. Alpha-2 receptors
D. Alpha-1 receptors
What is Tamsulosin?
=Flomax
- Alpha 1 blocker
- treats BPH
What is Phenoxybenzamine?
-irreversible alpha 1 blocker
-used to treat pheochromocytoma
(epinephrine secreting adrenal medulla tumor)
-antihypertensive used during surgery to remove tumor
What is Yohimbine
- Alpha 2 blocker
- Might treat erectile dysfunction? probs not, must be locally injected.
- Adverse effect: increase HR and BP
What is Terazosin?
- Alpha 1 bocker
- Treats hypertension
What do parasympathetic presynaptic alpha 2 receptors do?
-inhibit release of NT
What are the most significant adverse effects of alpha 1 blockers?
- postural/orthostatic hypotension
- reflex tachycardia
Why are combined a and B blockers useful? (labetalol, carvedilol)
a1 blocker dilates blood vessels; results in reflex tachycardia;
b1-blocker prevents increase in heart rate.
Drugs with multiple activities are some times very useful.
Bottom line: Decrease PVR and Blood Pressure, No change in Heart Rate & Cardiac Output
A patient was given a bolus dose of terazosin (Hytrin).
Question A. Terazosin belongs to what class of drug?
A. Alpha-1 agonist B. Alpha-1 blocker C. Beta blocker D. Alpha-2 blocker E. Beta-1 agonist
B. Alpha-1 blocker
***ZOSIN
A patient on spinal anesthesia goes into severe hypotension.
The drug of choice to correct this hypotension is:
A. Propranolol B. Isoproterenol C. Phenylephrine D. Clonidine E. Albuterol
C. Phenylephrine
What is the drug of choice to treat BPH (Benign Prostatic Hypertrophy) resulting in urinary retention?
A. Tamsulosin B. Phenylephrine C. Nitroglycerin D. Bethanechol E. Propranolol F. Terazosin
A. Tamsulosin
What causes schizophrenia?
-high dopamine (D2) in the limbic system
