Adrenergic Agents Flashcards
What are the 4 sympathomimetic effects of the CV system
Heart rate, CO, Peripheral vascular resistance, and venous return
What are the 2 potential mechanisms of Indirect-acting sympathomimetics?
- Displace stored catecholamines
2. Inhibit reputake of released neurotransmitter by interfering with NET
What are some examples of indirect acting sympathomimetics?
Amphetamines, Tyramine containing compounds, catecholamine reuptake inhibitors
What does Amphetamine do?
Release of stored NE and DA
CNS stimulant: increased mood and alertness, and decrease appetite
What does methamphetamine do?
Similar to Amphetamine, made from pseudo ephedrine
potent CNS action
What is Methylamphenidate used in?
ADHD (Aka Ritalin) Reduces reuptake of NE and improves its function in the brain
Name 2 additional indirect sympathomimetics other than amphetaimes and tyramine products.
Modafinil (Provigil) inhibits NE and DA transporters in CNS Exact mech is poorly understood Use to increase wakefulness w/ narcolepsy Armodafinil (nuvigil) R-enantiomer of modafinil Similar actions and uses to modafinil
What is Tyramine metabolized by?
MAO
What is the goal of catecholamine repute inhibitor?
Imbalance of NE and DA leads to different actions
- Atomoxetine (stratera), ADHD
- Sibutramine (Meridia) Serotonin and NE reuptake inhibitor, Approved as appetite suppressant
- Duloxetine (Cymbalta)-Serotinin and NE reuptake inhibotor used as an antidepressent
What is the action of Cocaine?
It is a catecholamine reuptake inhibitor
- inhibits preipheral repute of NET
- enters CNS produces amphetamine -like action but more intense
- inhibition of DA repute in pleasure center (very rapid addiction)
Therapeutic Application of Sympathomimetics: Hypotension
Goal increase BP and CO
- A1 agonist to Raise BP (NE, phenylephrine)
- Ionotropic agents in shock syndrome to increase CO (Dopamine, Dobutamine)
Therapeutic Application of Sympathomimetics: Hypertension
Goal decrease BP
1. Central acting A2 agonist manage HTN: Clonidine (Catapres)
Therapeutic Application of Sympathomimetics: Orthostatic HTN
Goal Increase BP
1. A1 agonist: Midrodine
Therapeutic Application of Sympathomimetics: Emergency Cardiac Measures
Goal Cardiac resusciation
1. A1 and B2 mediated actions - redistribute blood flow from less important areas to more important areas
Therapeutic Application of Sympathomimetics: Surgical
2 Goals-Reduce blood loss, Slow diffusion of anesthetics away from site of administration
- Reduce blood loss A1 activity-Epinehphrine/cocaine
- Slow diffiusion-Epi, NE, Phenylephrine
Therapeutic Application of Sympathomimetics: Sinus Decongestant
Goal Decrease Nasal Stuffiness
1. A1 Vasoconstriction in nasal passageways (Phenylephrine and oxymetazoline)
Therapeutic Application of Sympathomimetics: Pulmonary uses
Improve pulmonary airflow
B2 very commonly used in inhalers and nebulizers (Albuterol, metaproterenol, pirbuterol etc.)
Therapeutic Application of Sympathomimetics: Anaphylaxis
Reversal of vascular complications of immune hypersensitivity: symptoms of exposure to allergen can include shock due to cardiovascular and respiratory hypersensitivy response-bronchospasm, mucus membrane contestion,
1. Activate a1, b1, and b2 to reverse all symptoms
Therapeutic Application of Sympathomimetics: ophthalmic applications
multiple goals
Mydriasis-A1 agonist
Decongestant-A1 agonist
Reduction of intraocular pressure-A2 against (apraclonidine (lopidine), and brimonidine; alphagan)
Therapeutic Application of Sympathomimetics: GU applications
Delay delivery of baby: (aka tocolysis)
1. B2 selective used to relax uterus in preterm labor-Ritadine and terbutaline
Therapeutic Application of Sympathomimetics: CNS
Goal 1: Narcolepsy, and increase alertness and defer sleep Amphetamine, modafinil
Goal 2: Appetite suppression
Goal 3: ADHD management-Methylphenidate (ritalin), Dextroamphetamine (Adderall), Lisdexamfetamine (Vynase) prodrug for amphetamine
Therapeutic Application of Sympathomimetics: ICU sedation
Goal Improve pt comfort in ICU
A2 agonist- in combination with opioids, benzos and propofol lowers reuquirements of other drugs: (Dexmedetomidine)
Name the types of adrenergic receptors?
Alpha, beta
What are the names of the two enzymes that metabolize norepinephrine, epinephrine, and dopamine
MAO-monoamine oxydase
COMT-catecholomethyltransferase
What is NET and what does it do?
Norepinephrine transporter protein re-uptake NE and decreases NE activity; terminates adrenergic action
What effect occurs when the following receptors are stimulated by an agonist in the cardiovascular by an agonist in the cardiovascular system? For what medical conditions can these agents be used? A1 A2 B1 B2
A1-located in PVS: Vasoconstriction
A2-Peripheral: vasoconstriction (only when given locally or in high doses), Central: vasodilation drop BP
B1-located in heart: inc HR and CO
B2-Located in the PVS: vasodilation drops BP
What actions occur with use of adrenergic antagonists in following: CV Pulm Ocular Glucose Lipids
CV:
A1 antagonist-Vasodilation
B1 antagonist- dec HR and dec CO
B2 antagonist- vasoconstriction, Increase BP (not really)
Lungs:
B2 antagonist-Bronchoconstriction (careful with B blocker)
Eye:
Decreased IOP, Midriasis
Glucose: Block breakdown of lipid , blocks glucose mobility, decreases body ability to make more energy stores - worsens hypoglycemia
What is ISA
Intrinsic sympathomimetic activity-partial agonist activity of what was designed as a antagonist.
Limitations of B Blocker use?
leads to hypoglycemia, drop blood sugar, can worsen asthma, can worsen heart function in those with heart failure.
