Block 2 pharma Flashcards
Isoproterenol
Classification and main clinical applications
Classification:
• Sympathomimetic
• Nonselective beta agonist
Main clinical applications:
• Bronchodilator
Epinephrine
Classification and main clinical applications
Classification:
• Sympathomimetic
• Alpha1,2 / beta1,2 adrenergic agonist
Main clinical applications:
• Cardiac stimulant
• Bronchodilator
• Vasoconstrictor
Isoproterenol
Pharmacodynamics and adverse effects
Pharmacodynamics: Mechanisms/sites of action:
• B1 stimulation leads to positive inotropic and chronotropic effects
• B2 stimulation causes relaxation of bronchial smooth muscle and vasodilation in skeletal muscle
• As an inotrope, isoproterenol has largely been replaced by dobutamine, a B1 selective agonist
Adverse effects:
• Dizziness, flushing, headache; mild tremors
Epinephrine
Pharmacodynamics and adverse effects
Pharmacodynamics: Mechanisms/sites of action:
• Stimulation of alpha receptors leads to arteriolar vasoconstriction; increases gluconeogenesis and inhibits insulin release
• Stimulation of beta receptors induces positive chronotropic and inotropic responses
• Stimulation of beta2 receptors: increases glycogenolysis in liver and skeletal muscle
Adverse effects:
• Rapid heart beat, headache, tremors
Norepinephrine
Classification and main clinical applications
Classification:
• Sympathomimetic
• Alpha1,2/beta1 adrenergic agonist
Main clinical applications:
• Potent vasoconstrictor and positive inotropic agent
Norepinephrine
Pharmacodynamics and adverse effects
Pharmacodynamics: Mechanisms/sites of action
• Acts on alpha adrenergic receptors to induce vasoconstriction, resulting in increases in peripheral vascular resistance
• Acts on beta1 receptors, resulting in cardiac stimulation
Adverse effects
• Hypertension, local vasoconstriction
Dobutamine
Classification and main clinical applications
Classification:
• Sympathomimetic
• Selective B1 adrenergic agonist with weak B2 agonist activity
Main clinical applications:
• Increases myocardial contractility and stroke volume
• Short-term management of patients with cardiac decompensation
Dobutamine
Pharmacodynamics and adverse effects
Pharmacodynamics: Mechanisms/sites of action:
• Increases myocardial contractility in a dose-dependent manner acting on beta1 receptors
• Half-life is approx. 2 min (note: unlike dopamine, dobutamine does not affect dopaminergic receptors)
• Mild increase in vasodilation
Adverse effects:
• Increased BP, increased ventricular ectopic activity, sinus tachycardia
Phenylephrine
Classification and main clinical applications
Classification:
• Sympathomimetic
• Selective alpha1 adrenergic agonist
Main clinical applications:
• Vasoconstrictor used to treat nasal congestion
• Can be used topically to induce mydriasis
Phenylephrine
Pharmacodynamics and adverse effects
Pharmacodynamics: mechanisms/sites of action
• Agonist actions at alpha1 receptors
Adverse effects:
• Peripheral and visceral vasoconstriction, reflex bradycardia
Terbutaline
Classification and main clinical applications
Classification:
• Sympathomimetic
• Selective B2 adrenergic agonist
Main clinical applications:
• Bronchodilator used for the treatment of bronchospasm / asthma
Terbutaline
Pharmacodynamics and adverse effects
Pharmacodynamics: mechanisms/sites of action:
• Selective agonist actions at B2 receptors
Adverse effects:
• Central nervous system: nervousness
• Neuromuscular/skeletal: tremor
Alpha adrenergic partial agonists (oxymetazoline, tetrahydrozoline, naphazoline)
Classification and main clinical applications
Classification:
• Alpha adrenergic partial agonist
Main clinical applications:
• Nasal congestion associated with acute or chronic rhinitis, sinusitis, common cold, allergies
• Ocular decongestant to relieve eye redness
Alpha adrenergic partial agonists (oxymetazoline, tetrahydrozoline, naphazoline)
Pharmacodynamics and adverse effects
Pharmacodnamics: Mechanisms/sites of action:
• Intranasal and ophthalmic topical vasoconstrictor
• Stimulate alpha-adrenergic receptors; topical application to mucous membranes causes intense vasoconstriction resulting in shrinkage of mucous membranes; ophthalmic administration causes vasoconstriction of conjunctival blood vessels
Adverse effects:
• Transient burning, stinging, dryness of the nasal mucosa
• Upon discontinuation following prolonged use, rebound congestion can occur
Midodrine
Clissification and main clinical applications
Classification:
• Selective alpha1 adrenergic agonist
Main clinical applications:
• Symptomatic orthostatic hypotension
Midodrine
Pharmacodynamcis and adverse effects
Pharmacodynamics: Mechanism and sites of action:
• Vasoconstriction
• A prodrug that is metabolized to an active metabolite, desglymidodrine, that produces an increase in vascular tone and elevates BP
Adverse effects:
• Usually well tolerated
• Supine hypertension can occur
Clonidine
Classification and main clinical applications
Classification:
• Selective a2 adrenergic partial agonist
Main clinical applications:
• Antihypertensive agent (centrally acting)
• Analgesic
Clonidine
Pharmacodynamics
Partial agonist actions at presynaptic alpha2 receptors in the medulla brain region result in inhibition of sympathetic outflow and tone. Suppression of efferent sympathetic pathways decreases vascular tone in the heart, kidneys and peripheral vasculature; lowers peripheral resistance and reduces BP. Reflex tachycardia usually does not occur; reciprocal increase in vagal tone, causing an increase in baroreceptor activity and bradycardia.