Pharm REVERSE - adrenergic agonists Flashcards
agonist of a1, a2, B1
Norepinephrine
Effects:
1) Peripheral vasoconstriction
- increased peripheral vascular resistence (a1)
2) Increased blood pressure (a1)
3) can cause reflex bradycardia (vagally mediated)
Norepinephrine?
Therapeutic effects
1) used as a vasoconstrictor under certain intensive care situations (i.e. shock) (a1)
2) elevate blood pressure during reduced sympathetic tone (neurological injury or during use of spinal anesthesia) (a1)
Norepinephrine
agonist of a1, a2, B1, B2
Epinephrine
Effects:
1) Increased heart rate, contractile force, cardiac output
2) Increased systolic, decreased diastolic blood pressure
3) Constriction of most vascular beds but dilation of skeletal muscle blood vessels - net effect is to decrease peripheral vascular resistence
Epinephrine
Effects
Bronchodilation (B2)
Epinephrine and Isoproterenol
1) Hyperglycemia (stimulates gluconeogensis and glycogenolysis; inhibits insulin release)
2) Lipolysis - increase free fatty acids
Epinephrine
Therapys
1) rapid relief of hypersensitivity reactions to drugs and other allergens
2) Co-administered with local anesthetics to increase duration of action
3) Bradyarrhythmias - restore rhythm in patients with cardiac arrest
4) opthalmic uses - mydriatic, decrease hemorrhage, conjunctival decongestion
Epinephrine
Agonist of B1, B2
Isoproterenol
Effects
1) Decrease peripheral resistance
2) Increase heart rate, contractile force, cardiac output
3) Decrease mean blood pressure
Isoproterenol
Therapeutic use:
In emergencies to stimulate heart rate during bradycardia or heart block
Isoproterenol
agonist of DA1, B1, a1
Dopamine
Therapeutic use
severe decompensated heart failure, shock (cardiogenic; septic)
Dopamine
B1 agonist
Dobutamine
Effects:
1) Increased cardiac rate, contractility and output (B1)
2) Minimal change in peripheral resistence and blood pressure
Dobutamine
Therapys
1) short term treatment of cardiac decompensation (surgery, CHF, MI) (B1)
2) cardiac stress testing (B1)
Dobutamine
a2 receptor agonist
Methyldopa and Clonidine
Thearpeutic use:
anti-hypertensive (a2)
Methyldopa + clonidine
Side effects:
Sedation
dry mouth
edema
rebound hypertension with sudden discontinuation
Methyldopa + Clinidine (dry mouth in 50% of patients)
1) Phenylephrine
2) Clonidine
3) Albuterol
4) Salmeterol
What drugs are direct acting Adrenergic agonists that are non-catecholamines? (4)
a1 adrenergic agonist
Phenylephrine
Therapuetic use:
1) opthalmic: mydriatic, decrease hemorrhage, conjuctival decongestion (a1)
2) nasal decongestant: oral or nasal spray (a1)
3) used with local anesthetics to increase duration of action (a1)
4) treatment of hypotension (orthostatic hypotension, shock) i.v. administration (a1)
Phenylephrine
Effects:
1) Prolonged blood pressure lowering (a2 - CNS)
2) Decreased peripheral resistance, heart rate and cardiac output (a2 - CNS)
Clonidine
B2 adrenergic receptor agonist
Albuterol and Salmaterol
available only for inhalation
Salmeterol
duration of action = over 12 hours
Salmeterol
They release endogenous norepinephrine from nerve terminals
What is the mechanism of action for indirect acting adrenergic agonists?
Indirect acting adrenergic agonist
Tyramine
Increases norepinephrine release AND stimulates adrenergic receptors
mixed acting adrenergic agonist drugs
What are the Mixed acting adrenergic agonist drugs?
1) Amphetamine
2) Ephedrine
3) Pseudoephedrine
Powerful CNS stimulant
Is a weak direct alpha and beta agonist itself
What is the effect of Amphetamine?
1) Direct agonist of alpha and beta receptors
2) Releases NE that activates adrenergic receptors
Ephedrine
toxic plus weak CNS stimulation
Ephedrine
Direct a1 agonist (little B2 activity)
Pseudoephedrine
CNS stimulation, but less than Ephedrine
What is the effect of Pseudoephedrine?
