Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Endogenous Catecholamine
Agonist of α and β receptors; positive ionotropic (contractility) and chronotropic (rate) on heart (β1), vasoconstriction in vascular beds (α), and vasodilation in skeletal muscle blood vessels (β2) which may lower TPR
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tachycardia, arrhythmia, anxiety, hypertension, and acute pulmonary edema
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Cardiac arrest (increases cardiac output), anaphylaxis
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Endogenous catecholamine
Agonist of α1, α2, and β1 receptors but little effect on β2; increases TPR and BP, positive ionotropic effect on heart
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Ischemia, arrhythmias
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Hypotension, ADHD, depression
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Endogenous Catecholamine
Activates D1 receptors causing vasodilation of renal, splanchnic, coronary, cerebral, and other resistance vessels. Activation of D2 receptors suppresses norepinephrine release. Also activates β1receptors in heart and at high concentrations α receptors leading to vasoconstriction. Regulates Na+ secretion and renal function. Neurotransmitter in the CNS and is involved in reward system of addiction.
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Hypotension at high doses
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Parkinson’s disease (caused by a deficiency of dopamine in basal ganglia); Dopamine receptors are targets for antipsychotic drugs
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Direct-Acting Sympathomimetic
α1 agonist; vasoconstriction = ↑ arterial resistance and ↓ venous capacity, ↑ stroke volume causes ↑ CO, ↑ BP may cause reflexive ↓ HR; α1 r’s also constrict pupillary dilator muscle
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hypertension
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Decongestant, mydriatic (dilates pupil), can be used to increase BP
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Direct-Acting Sympathomimetic
α2 agonist; cause vasoconstriction when given locally, but systemically acts through CNS to decrease sympathetic tone and BP
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Dry mouth, sedation
Drowsiness
Impaired ejaculation
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hypertension
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Direct-Acting Sympathomimetic
α agonist with affinity for α2A receptor; promotes vasoconstriction of nasal mucosa
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Hypotension (central Clonidine-like effect)
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Topical decongestant
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Direct-Acting Sympathomimetic
Potent β1 and β2 agonist, positive chronotropic and ionotropic effects, vasodilator = ↑ CO, ↓ TPR and ↓ BP
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Tachycardia, dysrhythmias
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Bradycardia, heart block
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Direct-Acting Sympathomimetic
Β1 agonist; activate β1 receptors causing ↑ CO with less reflexive tachycardia because they do not activate vasodilator β2 receptors
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Hypertension, arrhythmias
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Heart failure, cardiogenic shock
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Mixed-Acting Sympathomimetic
Indirect stimulation of the adrenergic receptor system by increasing the activity of noradrenaline at α- and β-receptors, ability to cross blood-brain barrier into CNS makes it a mild stimulant
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Tachycardia, arrhythmias, various nervous system symptoms
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Ma huang (herbal medicine) decongestant, bronchodilator, weight loss
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Indirect-Acting Sympathomimetics
Acts as both a norepinephrine transporter (NET) substrate and reuptake blocker, eliciting reverse transport and blocking normal uptake = ↑ NE in synaptic cleft; release of NE and some dopamine; similar to ephedrine but enters CNS more readily
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Elevates CO and BP
CNS stimulation
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Marked stimulant effect on mood and alertness and depressant effect on appetite
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Indirect-Acting Sympathomimetics
Pharmacologic effects and abuse potential are similar to amphetamine (p.141); Block NET-mediated NE reuptake and enhance NE signaling similar to cocaine (p. 133) ???
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Nervousness, drowsiness, insomnia
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ADHD, narcolepsy
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Indirect-Acting Sympathomimetics
Inhibits both norepinephrine and dopamine transporters; increases interstitial concentrations not only of norepinephrine, dopamine, serotonin, and glutamate; decreases GABA levels
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Increase in BP and HR
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Improves wakefulness in narcolepsy and some other conditions
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Indirect-Acting Sympathomimetics
Indirect sympathomimetic action caused by release of stored catecholamines = action similar to NE; readily metabolized by MAO in liver = high first-pass effect
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Increase in BP
Hypertensive crisis
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Patients treated with monoamine oxidase (MAO) inhibitors may have intensified Tyramine effect (must avoid Tyramine containing foods like cheese)
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Catecholamine Reuptake Inhibitor
Inhibits transmitter reuptake at noradrenergic synapses; enters CNS and inhibits dopamine reuptake into neurons in the “pleasure centers” of the brain
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Tachycardia, hallucinations, paranoid delusions; overdoses cause tachyarrhythmias and a marked ↑ BP, which can be life-threatening. CNS stimulation
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Heavily abused drug - produces amphetamine-like”psychological effects that is shorter lasting and more intense
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Dopamine Agonist
D1 agonist; activates adenylyl cyclase; causes vascular smooth muscle relaxation
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hypotension, reflex tachycardia, ↑ intraocular pressure
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hypertension
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Term
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Definition
CH 9 Adrenoceptor Agonists & Sympathomimetic Drugs
Dopamine Agonist
D2 agonists; inhibits adenylyl cyclase and interacts with other intracellular pathways; restores dopamine actions in the CNS
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Orthostatic hypotension
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Parkinson’s disease, prolactinemia
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