Androgenic Drugs Flashcards
(31 cards)
Phenylephrine
-direct acting alpha agonist
-a1 > a2
– Not a catechol
– not inactivated by COMT
– longer duration of action
– Effective mydriatic and decongestant
– Causes severe vasoconstriction and blood pressure elevation
– Role of baroreflex
– Hypotensive emergencies – hemorrhagic shock, overdose of antihypertensives, CNS depressants
-Decongestion of mucous membranes
- Examination of retina – induction of mydriasis
-injected into penis to treat priapism (extended erection)
Methoxamine
-direct Acting alpha agonist
-a1>a2
– Hypotensive emergencies – hemorrhagic shock, overdose of antihypertensives, CNS depressants
Clonidine
-direct acting alpha agonist
-a2 > a1
– Central effect on a2 receptors in the lowerbrainstem area
-Decreasing sympathetic outflow
-Reduction in blood pressure
-Bradycardia
– Local application produces vasoconstriction
•Activates a2 receptors in the vasomotor center of the brain
•Reduces sympathetic nervous system activity in the body
•Reduces peripheral vascular resistance, decrease heart rate and cardiac output
Norepinephrine
-direct acting alpha and beta agonist
- a1 = a2 ; B1»_space; B2
– Potent cardiac stimulant but reduces heart rate
– Potent vasoconstrictor
– Lacks B2 agonist effects
– no bronchodilation andvasodilation
– Increases peripheral vascular resistance and blood pressure
– Role of baroreflex
-Hypotensive emergencies – hemorrhagic shock, overdose of antihypertensives, CNS depressants
Epinephrine
-direct acting alpha and beta agonist
-Effects of cardiac function (B1)
– Increases the force of contraction
-positive inotropic effect
– Increases heart rate
– Increases conduction velocity at AV node
• Effects on vascular tone (B2 and a1)
– Increases systolic BP
– May decrease diastolic BP and total peripheral vascular resistance
– Mean arterial pressure often remains unchanged
• Effects on respiratory system
– Relaxes bronchial muscle (B2)
– Decreases bronchial secretion and congestion within bronchial mucosa (a1)
• Other effects
– Effects on skeletal muscle
-Causes muscle tremor (B2)
-Increases K+ uptake by skeletal muscle (B2)
– Promotes hypokalemia and decreases K+ excretionby kidneys
– Elevates blood glucose levels
-Enhances liver glycogenolysis (B2)
-Inhibits insulin release (a2)
– Increases free fatty levels in blood (B)
– Increases renin release (B1)
-for complete AV block and cardiac arrest
-used as Anaphylaxis – immediate (type 1) allergicreaction characterized by respiratory and cardiovascular components
Dobutamine
-direct acting beta agonist
- B1 > B2 , a1
– Selective B1 agonist
– a1 receptor activity
-(-) isomer is an agonist at these receptors while (+) isomer is an a1 antagonist
– Potent inotropic action
– Less prominent chronotropic action as compared to isoproterenol
- Cardiogenic shock – due to massive acutemyocardial infarction
-short term use in heart failure
Isoproterenol
-direct acting beta agonist
-B1= B2
– Non-selective beta agonist
– Positive inotropic and chronotropic action, increases cardiac output (B1)
– Vasodilator, decreases arterial pressure (B2)
– Causes bronchodilation (B2)
-for complete AV block and cardiac arrest
Terbutaline
-direct acting beta agonist
-Selective B2 agonists
– Cause bronchodilation and relaxation of the uterus
-Bronchial asthma
- Suppression of premature labor
Albuterol
-direct acting beta agonist
-Selective B2 agonists
– Cause bronchodilation and relaxation of the uterus
-Bronchial asthma
Dopamine
-direct acting dopamine agonist
-D1= D2»_space; B1» a1
-D1 stimulation causes vasodilation
–High density of D1 receptors in renal, cerebral, mesenteric and coronary vessels
-Activation of presynaptic D2 – suppresses norepinephrine release
-Activates B1 in heart at higher doses
-At still higher doses stimulates vascular a1 AR to cause vasoconstriction
- Cardiogenic shock – due to massive acutemyocardial infarction
-use in congestive severe HF with reducedrenal perfusion
Fenoldopam
- direct acting dopamine agonist
- for hypertensive emergencies
Cocaine
-indirect androgenic agonist
- Inhibits re-uptake of DA and NE
- Inhibits transmitter reuptake at adrenergic synapses
• Peripheral and intense central adrenomimetic action
• Local anesthetic properties
-lipophilic, can easily pass BBB
Adverse affects
• Convulsions
• Arrhythmias
• Hemorrhagic stroke
Selegiline
- indirect androgenic agonist
- Inhibitors of MAO so norepinephrine can’t be degraded
Phenelzine
- indirect androgenic agonist
- inhibitors if MAO so norepinephrine can’t be degraded
Methylphenidate
- indirect androgenic agonist
- Reverse NE and DA uptake mechanism and increase their release
- Usually more lipophilic compounds
- Easily penetrate BBB – have significant central effects – central nervous system stimulants
- Mild alerting effects
- Improved attention
- treats Narcolepsy, ADHD
Tyramine
-indirect androgenic agonist
-a byproduct of tyrosine metabolism, not a drug
- Reverse NE and DA uptake mechanism and increase their release
– accumulates in protein-rich foods during fermentation
• Readily metabolized by MAO in the liver (very high first-pass effect)
• If administered parenterally, affords indirect sympathomimetic action caused by release of stored catecholamines (norepinephrine-like
effect)
Ephedrine
-indirect androgenic agonist
- Releasing agent AND direct adrenergic receptor agonist
-releases stored catecholamines with some direct adrenomimetic action
• Plant constituent
• Non-catechol
–Long duration of action
–Effective after oral administration
• Nonselective – similar to epinephrine in actions
• Mild stimulant – enters CNS
- for Chronic hypotension
-Decongestion of mucous membranes
- Stress urinary incontinence
-Obesity – central inhibition of appetite andincreased energy expenditure
Amphetamine, methamphetamine
-indirect androgenic agonist
-Usually more lipophilic
-Easily penetrate BBB – have significant central effects – central nervous system stimulants
• Mild alerting effects
• Improved attention
- Reverse NE and DA uptake mechanism and increase their release
-treats Narcolepsy
-Obesity – central inhibition of appetite andincreased energy expenditure
Adverse affects • Insomnia • Lack of appetite • Anxiety, restlessness • Psychoses (paranoid state, hallucinations)
Apraclonidine, brimonidine
- Alpha-2 selective agonists
- treats glaucoma
Guanethidine
-indirect acting androgenic antagonist
- Norepinephrine release inhibitor
• Mechanism of action
–Taken up by the reuptake mechanism
–Replace norepinephrine in vesicles
–Cause a gradual depletion of norepinephrine stores
–Inhibition of norepinephrine release via local anesthetic properties
- used in chronic hypertension
Metyrosine
- indirect acting androgenic antagonist
- Inhibitor of tyrosine hydroxylase
- treats Pheochromocytoma
Phentolamine
- direct acting Non-selective (a1 and a2) receptor antagonists
- a competitive α antagonist
- can treat Pheochromocytoma
- injected into penis to treat erectile dysfunction
Phenoxybenzamine
- direct acting Non-selective (a1 and a2) receptor antagonists
- a non-competitive irreversible α antagonist
- can treat Pheochromocytoma
Prazosin, Terazosin, Tamsulosin, Doxazosin, Alfuzosin, Silodosin
All end In “Oisin”
-direct acting a1 receptor selective androgenic antagonist
- treat chronic hypertension
-used in Benign prostate hyperplasia (BPH) – to treat chronic urinary obstruction
• Greater selectivity for a1A than a1B
• a1A is the most important a receptor subtype mediating prostate smooth muscle contraction
• Effectively relieves urinary obstruction and pain with little effect on blood pressure
