pharmacology test 3 Flashcards
drugs that mimic the effects of SNS neurotransmitters
Norepinephrine (NE), Epinephrine (EPI), Dopamine
Alpha1-adrenergic receptors
Located on postsynaptic effector cells (the cell, muscle, or organ that the nerve stimulates)
Alpha2-adrenergic receptors
Located on presynaptic nerve terminals (the nerve that stimulates the effector cells)
Control the release of neurotransmitters
Alpha-Adrenergic Agonist Responses
vasoconstriction and CNS stimulation
Beta1-adrenergic receptors
located primarily in the heart
Beta2-adrenergic receptors
located in smooth muscle of the bronchioles, arterioles, and visceral organs
Catecholamines
produces a sympathetic response
Endogenous: epinephrine, norepinephrine, dopamine
Synthetic: dobutamine, phenylephrine
Catecholamines are metabolized by
Monoamine oxidase (MAO) - wow you know like MAOI’s
Catechol ortho-methyltransferase (COMT)
Adrenergic Drugs Effect
Vasoconstriction of blood vessels, relaxation of GI smooth muscles (decreased motility), constriction of bladder sphincter, contraction of uterus, male ejaculation, contraction of pupillary muscles of the eye (dilated pupils)
Increased force of contraction (positive inotropic effect)
Increased heart rate (positive chronotropic effect)
Increased conduction through AV node (positive dromotropic effect)
Adrenergic Indications: Respiratory
Bronchodilators: drugs that stimulate beta2-adrenergic receptors of bronchial smooth muscles, causing relaxation, resulting in bronchodilation
Examples: albuterol, ephedrine, epinephrine, formoterol, levalbuterol, metaproterenol, pirbuterol, and salmeterol
Adrenergic Indications: Nasal Congestion
Intranasal (topical) application causes constriction of dilated arterioles and reduction of nasal blood flow, thus decreasing congestion.
Examples: ephedrine, naphazoline, oxymetazoline, phenylephrine, and tetrahydrozoline
Adrenergic Indications: Ophthalmic
Temporary relief of conjunctival congestion (eyes)
Alpha-adrenergic receptors
Examples: epinephrine, naphazoline, phenylephrine, tetrahydrozoline
Reduction of intraocular pressure and dilation of pupils: treatment of open-angle glaucoma
Alpha-adrenergic receptors
Examples: epinephrine and dipivefrin
Adrenergic Indications: Overactive Bladder
Relaxes the detrusor muscle during the storage phase of the bladder fill cycle
Increases bladder storage capacity
mirabegron (Myrbetriq)
Cardiovascular Indications Vasoactive Adrenergics (Pressors, Inotropes)
Also called cardioselective sympathomimetics
Used to support the heart during cardiac failure or shock; various alpha and beta receptors affected
Vasoactive Sympathomimetics (Pressors, Inotropes): Examples
Dobutamine, ephedrine, fenoldopam, midodrine
Dopamine, epinephrine, phenylephrine, norepinephrine
Contraindications for Pressors
known allergy and severe hypertension
Adverse Effects of Alpha-adrenergic Drugs
Headache, restlessness, excitement, insomnia, euphoria
Chest pain, vasoconstriction, reflexive bradycardia, palpitations, dysrhythmias
Anorexia, dry mouth, nausea, vomiting, taste changes
Adverse Effects of Beta-Adrenergic Drugs
Mild tremors, headache, nervousness, dizziness
Increased heart rate, palpitations, fluctuations of blood pressure
Sweating, nausea, vomiting, muscle cramps
Adrenergic Drugs Overdose and Toxicity
From excessive CNS stimulation: seizures
Intracranial bleeding due to extreme elevation of blood pressure
Effective treatment: rapid acting sympatholytic drug. They have short half-lives, thus effects are short-lived
Symptom management and support the respiratory and cardiac systems
Adrenergic Drugs Interactions
Adrenergic antagonists
Anesthetic drugs
MAOIs
Antihistamines
Thyroid preparations
usually has a decreased effect of the meds
Dobutamine
similar to dopamine
Stimulates beta1 receptors on heart muscle (myocardium); increases cardiac output by increasing contractility (positive inotropy), which increases the stroke volume, especially in patients with heart failure.
Intravenous drug; given by continuous infusion
Short term treatment of heart failure. Beta1 selective vasoactive drug. Similar to dopamine but this is synthetic. Can give the patient chest pain, if the patient already has a heart problem it will make it worse.
Dopamine
Naturally occurring catecholamine neurotransmitter
Potent dopaminergic as well as beta1- and alpha1-adrenergic receptor activity
Low dosages: can dilate blood vessels in the brain, heart, kidneys, and mesentery, which increases blood flow to these areas (dopaminergic receptor activity)
Higher infusion rates: improve cardiac contractility and output (beta1-adrenergic receptor activity)
Highest doses: vasoconstriction (alpha1-adrenergic receptor activity)
preferred drug for patients in shock, IV on a titrated line
Epinephrine
Administered in emergency situations – epipen given subQ
One of the primary vasoactive drugs used in many advanced cardiac life support protocols
Can be given to dead people when trying to pull a Frankenstein
“ACLS think epi” -we can give it as long as we need to, there is no stopping point
Norepinephrine (Levophed)
Causes vasoconstriction
Direct-stimulating beta-adrenergic effects on the heart (beta1-adrenergic receptors)
No stimulation to beta2-adrenergic receptors of the lung
Treatment of hypotension and shock
Administered by continuous infusion titrated drip