Adrenergic Agonists Flashcards
What is the primary neurotransmitter of the SNS?
norepinephrine (NE)
Define: Adrenergic drugs
drugs that mimic the effects of NE and Epi
Define: Direct-acting Adrenergic Agonists
drug binds directly to the receptor- postsynaptic site of action
Define: Indirect-acting Adrenergic Agonist
increases the availability of NE/Epi
-causes release of NT
-blocks reuptake of NE
-inhibits metabolism
Define: Monoamine Oxidase (MAO)
found in the cytoplasm of adrenergic neurons, metabolizing the primary amine (secondary and tertiary amine reduces ability for MAO to act)
Define: COMT
located in the synapse, metabolizes catechol groups
What is the clinically utility of beta-adrenergic agonists?
-asthma and COPD (beta2)
-stimulate heart (increased contractility, increased heart rate) (beta1)
-prevent pre-term labor
What drug classes that we have learned so far can treat Asthma?
-anticholinergics
-long-acting beta2 agonists (LABA)
-short-acting beta2 agonists (SAMA)
Adverse Effects: Beta2 Agonist
-tremors (beta2 in skeletal muscle)
-tachycardia (small portion of beta2 receptor in the heart) or from baroreceptor reflex due to decreased BP (vasodilation from beta2 in skeletal muscle)
What is the clinical utility of alpha agonists?
-hypotension (alpha1)
-decongestants (alpha1)
-hypertension (alpha2)
Describe: Phenylephrine
-selective alpha1 for vasoconstriction
-can be used systemically for hypotension during surgery
-can be used locally to reduce bleeding during surgery for better view, eye drops for red eyes, reduces swelling and congestion of nasal passages
Describe: alpha2 agonists
negative feedback, so lowering SNS activity by decreased NE release
What are the determinants of BP?
CO=HR x SV
BP= CO x TPR
Rank Endogenous catecholamines potency at alpha1 receptors:
epi > NE > iso (beta specific)
Rank Endogenous catecholamines potency at beta1 receptors:
iso > epi > NE
