Chapter 9: Sympathomimetics Flashcards
A drug that decreases appetite
Anorexiant
A synthetic sympathomimetic with isopropylamine in its structure (eg, amphetamine, ephedrine). Unlike catecholamines, these usually have oral activity, a long half-life, CNS activity, and cause release of stored catecholamines
Phenylisopropylamine
Type of adrenoceptors outside the CNS found in adipocytes, which stimulates lipolysis
Beta 3
Type of adrenoceptors outside the CNS found in adipocytes, which inhibits lipolysis
Alpha 2
Type of adrenoceptors outside the CNS found in most vascular smooth muscle responsible for contraction
Alpha 1
Type of adrenoceptors in the heart (stimulates rate and force) and the juxtaglomerular cells of kidney (stimulates renin release)
Beta 1
What is the drug of choice for the immediate treatment of anaphylactic shock (hypotension, bronchospasm, angioedema) because it is an effective physiologic antagonist of many of the mediators of anaphylaxis?
Epinephrine
Noncatecholamine alpha-selective sympathomimetic used as decongestant, mydriatic, neurogenic hypotension
Phenylephrine
Noncatecholamines beta 2-selective agonist used for acute bronchospasm
Albuterol, metaproterenol, terbutaline
What is the primary transmitter at the sympathetic postganglionic neuron-effector cell synapses in most tissues? (except: eccrine sweat glands and vasodilator sympathetic fibers in skeletal muscle)
Norepinephrine
Inhibits synthesis of dopamine by inhibiting hydroxylation of tyrosine to DOPA (enzyme: tyrosine hydroxylase)
Metyrosine
Blocks the transfer of DOPA into vesicles
Reserpine
Inhibits entry of calcium triggers interaction among SNARE proteins (VAMPs and SNAPs)
Guanethidine
Promotes entry of calcium triggers interaction among SNARE proteins (VAMPs and SNAPs)
Amphetamines and Tyramine
Inhibits diffusion and reuptake of Dopa via NET and DAT in synaptic cleft
Cocaine and TCAs
Adrenoceptor that stimulates platelet aggregation
Alpha 2 adrenergic agonist
Sympathomimetic (non-selective, direct-acting)
b1 = b2 > a
Used for severe Asthma, COPD, hemostasis
Epinephrine
Sympathomimetic (non-selective, direct-acting)
a > b1»_space; b2 (almost negligible)
First line treatment for refractory hypotension in severe sepsis
Norepinephrine
Dose-dependent actions of dopamine:
LOW DOSE (0.5 to 3 mcg/kg/min)
- D1 and D2 receptors
- Vasodilation, decreased arterial BP and increased renal and splanchnic blood flow
MEDIUM DOSE (3-10 mcg/kg/min)
- β1 receptors
- Increased CO (chronotropy and contractility)
HIGH DOSE (>10 mcg/kg/min)
- α1 receptors
- Leads to arterial and venous vasoconstriction, increased SVR, increased BP and increased CO
A non-selective beta adrenergic receptor agonist
used in asthma and for sustained increases in HR (during pacemaker insertion for bradydysrhythmia)
Isoproterenol
albuterol or salbutamol is beta-2 selective
Drug of choice for Alpha-1 agonist overdose
Phentolamine
Pseudoephedrine is avoided in the 1st trimester because it may be associated with possible risk of:
Gastroschisis
A unilateral condition that results from interruption of sympathetic nerves to the face. Symptoms include vasodilation, ptosis, miosis and loss of sweating on the affected side.
Horner’s syndrome
Activates a2 adrenergic receptors by decreasing central sympathetic outflow (lowering peripheral vascular resistance), used in preeclampsia and gestational HPN
Methyldopa
Sympathomimetic of choice for:
Acute heart failure, septic shock
Goal:
Increased cardiac output
Beta 1 and D1 agonists
Sympathomimetic of choice for:
Hemostasis, decongestion, and spinal shock
Goal:
Vasoconstriction and temporary maintenance of BP
Alpha 1 agonist
Sympathomimetic of choice for:
Bronchospasm, premature labor
Goal:
Bronchodilation, uterine SmM relaxation
Beta 2 agonist
Sympathomimetic of choice for:
Hypertension, glaucoma
Goal:
Decrease BP
Alpha 2 agonist
