Sympathomimetics II: Examples of Synthetic Agonists Flashcards
What is oxmetazoline
its a sympathomimetic– a non selective alpha agonist and a synthetic
What are some other names for oxymetazoline?
generic, afrin, neo-synephrine 12 hour and many other over the counter nasal soultions
Whay is oxymetazolined used for?
its used for the short term treatment of nasal decongestion
relief of redness of the eyes from cold swimming and contacts
What are the formulations of oxymetazoline and what is important about these routes?
nasal: spray or drops
ophthalmic: drops
both route can lead to systemic absorption
What is the mechanism of action of oxymetazoline for nasal administration?
is the direct administration of alpha-receptors in the nasal mucosa-vasoconstriction; results in decreased blood flow and decreases congestion
What is the mechanism of action for ophthalmic administration?
the activation of alpha receptors- vasoconstriction in the arterioles of the conjunctiva; it result in decreased conjunctival congestion
What are the side effects of oxymetazoline?
headaches
nervousness
trouble sleepting
What side effects can nasal administration of oxymetazoline have on the body?
results in rebound congestion, buring of the nasal mucosa and sneezing
What effects does opthalmic administration of oxymetazoline have on the body?
results in rebound irritation, conjunctivitis with long term use
What are the drug interactions of oxymetazoline?
TCA- significant systemic absorption of oxymetazoline could lead to tachycarida and arrhythmias
What conditions are oxymetazoline contraindicated with?
heart disease, hypertension, and diabetes
What is phenylephrine?
its an alpha agonist; synthetic; sympathomimetic
What is are the other names for phenylephrine used to treat nasal congestion?
sinex, neo-synephrine- treatment of nasal congestion
What are neo-synephrine and neo-synephrine, relief?
neo-synephrine, relief: is used as a mydriatic (diagnostic) and conjuctival decongestant
neo-synephrine- usedd for acute hypotension and as an adjunt to local anesthesia
What are the nasal forms of phenylephrine and what is their duration of action?
spray or drops
duration of action is 30 min to 4 hours
How is opthalmic of phenylephrine administered and how long do its effects last ?
solution, effects occur within 30 min; last up to 3 hours
Where can phenylephrine be given or how is it dosed?
can be given IV, SC, and IM
What is the onset of action of IM and SC phenylephrine?
its 10-15 min
What is the onset of action of IV phenylephrine?
its immediate
How is phenylephrine metabolized?
its not broken down by COMT (because it has only one hydroxyls)—longer duration of action
What happens to the application of nasal and opthalmic routes when using phenylephrine?
can lead to systemic absorption
What is the mechanism of action of phenylephrine on nasal stuructures?
activation of alpha-1 results in vasoconstriction of the arterioles of the nasal mucosa
What is the mechanism of action of phenylephrine on the ophthalmics?
stimulation of alpha-1 receptors contracts the dilatory muscle of the pupil producing mydriasis. the alpha receptor activation constricts the arterioles of the conjuctiva to decreas congestion
What is the mechanism of action of systemic phenylephrine?
vasopressor-activates alpha-1 receptors to produce vasocontriction; an increase in total peripheral resistance occurs with an elevation in both systolic and diastolic blood pressure; the pressor effect leads to pronounced bradycardia via the vagus
What is the mechanism of action of phenylephrine with anesthetic adjunct?
constricts the vessels in the skin, mucous membranes and viscera (GI) via—alpha-1 receptor activation;
this decreases the rate of vascular absorption of the local anesthetics thereby prolonging their duration of action and decreasing the risk of to toxicity
What are the side effects of phenylephrine on the nasal structure?
its the same as oxymetazoline
What are the side effects of phenylephrine on opthalmics?
tachycardia, vomitting, tingling in the hands and feet and headache
What are the side effects of alpha-agonist on the CNS?
dizzinines
nervousness
restlessness
trembling
What
What is the inhalation anesthetics and phenylephrine?
increased risk of arrhythmias and senstization of the myocardium to sympathomimetics
What are the drug interactions beteween local anesthetics and phenylephrine?
may cut off blood flow to fingers and toes
What is the drug interaction between TCA and Cocaine + phenylephrine?
potentiation of the cardiovascular effects of these drugs manily tachycardia and arrhythmias
What is the drug interaction between phenylephrine and beta blockers?
unopposed alpha-receptor activity resulting in hypertension; inhibition of therapeutic effects
What is the drug interaction between digitalis and phenylephrine?
increased risk of arrythmias
What is the drug conbination between ergot dervatives and phenylephrine?
potentiated vascoconstriction, hypertension
What is the drug interaction between MAO inhibitors or phenylephrine?
potentiates and prolongs effects of phenylephrine; increased risk of hypertension and arrhythmias
What is clonidine?
its a selective alpha-2 agonist
What are some more commerical names for clonidine?
Oral; Catapres
generic, Transdermal; Catapres TTS
What is clonidine used for?
used for the treatment of hypertension, usually a step II addition or substitution
and treatment of hypertensive emergencies
What are the non-label uses of clonidine?
non-label uses include amelioration of nicotine and opiate withdrawal symptoms which are CNS mediated
How does the oral dose interact with the body?
the oral dose is well-absorbed duration of antihypertensive action is about 8 hours
Where is the clonidine transdermal patch located and what is its druation of action?
it is placed on the chest or upper arm–the drug is absorbed at a constant rate and the duration of action is between 7 dyas when the patch is presnent and for 8 hours folloing removal
What are characteristics of clonidine?
its lipophilic and crosses the BBB
What is the mechanism of action of clonidine?
it is an anti-hypertensive- agonist at alpha 2 receptors; activation of alpha 2 receptors in the central nervous systerm decreases sympathetic outflow (decreased NE release) to the heart, kidneys and preipheral vasculature; results in a decrease in total peripheral resistance, diastolic and systolic blood pressure and heart rate
What are some withdrawl symptoms of clonidine?
a reduction in sympathetic outflow and inhibition of the locus ceruleus in the brain (an NE containing nucleus)
What are the side effects of clonidine?
itching and redness with the use of the patch
drug mouth with oral use
drowsiness
dizziness
rebound hypertension in 5-20% of patients especially following abrupt cessation of use
What are the drug interactions of clonidine with TCAs and appetite suppressants?
may decrease the anti-hypertensives effects
What are the drug interactions of beta blockers with clonidine?
discontinuation of both beta-blocker and clonidine simultantaneouly can increase risk of rebound hypertension
How should the patient be taken of beta blocker while on clonidine?
discontinue the beta blocker first several days before ending the clonidine
What is important for clonidine to work properly?
compliance is essential for clonidine to work properly
What isoproteranol?
its a non-selective beta agonist
What are the commerical names of isoperoteranol?
Aerolene
Isuprel
Medi-Haler
Vaps-Iso
What is isoproteranol used for?
its used as a bronchodilator for the treatment of:
asthma
bronchitis
emphysema
bronchospasm
obstructive pulmonary disease
its not the first choice ofor prophylaxis of this disease
What else can isoproteranol used for?
its a cardiac stimulate for treatment of cardiac arrest and standstill, Adam-Stokes syndrome and AV block (both are forms of syncope which is altered consciousness due to reduced blood flow to the brain, fainting), carotoid sinus hypersensitivity and ventricular tachycardia and arrhythmia, bradycardia and hypo-perfusion syndrome (shock)
What are the forms of isoproteranol that lead to rapid absorption?
inhalation and parenteral administration
What are the forms of administration of isoproteranol that lead to variable absorption?
sublingual and rectal administration
Where can isoproteranol enter?
it can enter the breast milk
What contraindications of dobutamine?
hypovolemia
myocardial infarction
idiopathic hypertrophic subaortic stenosis
What is the mechanism of action for the brochioles for isoproteranol?
agonist at beta-2 receptors in the lungs; this results in the dilation of bronchial smooth muscle, leading to reduced airway reistance and increasing lung capacity; activation of the beta-2 receptors increase cAMP production which relaxes the smooth muscle and also inhibits the release of mediators (such as histamine) of hypersensitivity from mast cells
What is the mechanism of action of isoproteranol on cardiac stimulation?
an agonist of beta-1 receptors on the heart; this produces an increase in heart rate (positive chronotropic) via the sino-atrial node; an increase in the force of contraction (positive inotropic) in the myocardium; increase in the conduction velocity-shortening the refractory period of AV node
What is the mechanism of action of isoproteranol and peripheral vasculature?
produces dilation of the smooth muscle surrounding the vasculature of the skeletal muscle va the beta-2 receptor; this relieves the intensive vasoconstriction that occurs after hypovolemic shock.
What are the side effects of isoproteranol?
dry mouth and throat
nervousness and restlessness
trouble sleeping
pinkish saliva
At what point which taking isoproteranol should a doctor be seen?
a doctor should be seen with persistent: chest pain, dizziness, severe headache, large increase in blood pressure, irregular or fast heart beat, severe weakness, and nausea and vomitting.
What is the drug interaction of isoproteranol with inhalation anesthetics?
increased risk of arrhythmias and sensitization of the myocardium to sympathomimetics
What are the drug interactions of isoproteranol and TCA and Cocaine?
potentiation of the cardiovascular effects of these drugs mainly tachycardia and arrhythmias
What is the drug interaction between beta blockers and isoproteranol?
unopposed alpha-receptor activity resulting in hypertension; inhibition of therapeutic effects
What is the drug interaction between digitalis and isoproteranol?
increased risk of arrhythmias
When is isoproteranol contraindicated?
in most forms of heart disease
What is dobutamine?
its a beta-1 selective agonist
When is dobutamine used?
injection: dobutrex
What is dobutamine used to treat?
used for treatment of cardiac decompensation (inablility to maintain adequate circulation) secondary to depressed contractility (as opposed to vascular damage) resulting from CHF and cardiac surgery
How is dobutamine administered and what is its duration of action?
its give IV- onset of action is immediate; its duration of action is minutes
What is the mechanism of action of dobutamine?
a direct acting inotropic agent, it stimulates beta-1 receptor on the heart to increase myocardial contractility and stroke volume; results in an increase in cardiac output
What does dobutamine do to blood flow?
it increase the coronary blood flow and oxygen consumption
the systemic vascular resistance is decreased (afterload reduction) however systolic blood pressure and pulse pressure remain unchanged due to increased cardiac output
What does dobutamine do to AV node conduction?
facilitates AV node conduction; renal blood flow and urine output is increased due to the increase in cardiac output
What are the side effects of dobutamine?
an increase in systolic blood pressure of 10 to 20 mmHg in most patients but some patients can have an increase of over 50 mmHg
increase in heart rate of 30 or more BPM
premature ventricular beats
no major drug interactions
What is terbutaline?
a selective beta 2 agonist
What are commerical names terbutaline?
inhalation; brethaire, oral;
brethine
bricanyl
What is terbutaline used for?
as a bronchodilator for the same indications as isoproteranol as for the prophylaxis of asthma and bronchospasm
What are some other uses of terbutaline?
its used for the treatment of prophylaxis premature labor
What is the onset of action terbutaline?
60-120 min; while for inhalation its 5-30 min; it has a slow onset compared to other anti-asthmatics
What is the mechanism of action for terbutaline?
selective agonist for beta-2 receptors which causes the relaxation of smooth muscle in the bronchi and uterus
What are the side effects of terbutaline?
restlessness and nervousness
trembling
trouble sleeping
doctor should be seen with persistent: chest pain, dizziness, severe headache, large increase in blood pressure, irregular or fast heart beat, severe weakness, nausea and vomitting
What are the drug interaction of terbutaline with inhalation anesthetics?
increased risk of arrhythmias and sensitixation of the myocardium to sympathomimetics
What are the drug interactions of terbutaline with TCA and cocaine?
potentiate cardiovascular effects of these drugs mainly tachycardia and arrhythmias
What are the drug interactions of terbutaline with beta blockers?
unopposed alpha receptors activity resulting in hypertension; inhibition of therapeutic effects
What does drug interactions of terbutaline and digitalis have?
increased arrhythmias
what is the drug interaction between MAO inhibitors and terbutaline?
potentiated effects on vasculature
What is albuterol?
its a beta two selective agonist
What is commerical name for albuterol?
ventolin, proventil
What are the pharmacological properties and therapeutic indication of albuterol?
they are similare to terbutaline–considered more bronchoselective in effects
How is albuterol administered?
What is ritodrine?
its is a beta-2 selective agonist
What is its use and what are its pharmacological properties?
is used specifically for the use of uterine relaxant
the pharmacological properties resembles those of other agents
How is ritodrine administered?
it can be administered intravenously to selected patients to arrest premature labor; can prolong pregnancy
How is ritodrine’s pharmacokinetic properties?
are complex and incompletely defined, especially in pregnant women
What are salmeterol?
Its a long acting beta-2 selective agonist
What is another commerical name for salmeterol?
serevent
What is formoterol?
its a long acting beta selective agonist
What is a commerical name for formoterol?
its foradil
What is salmeterol and formoterol
and how do they achieve their effect ?
they are a new generation of long acting (12 hour or more) beta-2 selective agents.
they acchieve their effect due to their high lipid solubility; agents dissolve in the smooth muscle membrane in high concentrations (one other postulated mechanism is that they attach to mooring proteins close to beta-receptors)
this allows slow constant release over a long period of time; agents are not recommended for asthma monotherapy
What are the long action beta-2 selective agonist agents used for?
salmeterol and formoterol are agents of choice for treating nocturnal asthma despite anti-inflammatory management of the use of other agents
What is the benefit of combining salmeterol and formoterol with corticosteroids?
they are highly efficacious when combined with corticosteroids
What can salmeterol and formoterol not be used for?
not relief of acute asthma attacks- not a rescue inhaler
How should long acting beta-2 selective agonist be taken with?
give with anti-inflammatory agents ; it is recommended patients are optimized on these agents before long acting beta-2 agonist given
what is so dangerous about long acting beta-2 selective agonist?
it has been shown that monotherapy may increase death
