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Are the two types of propellants used w/ pMDIs.
CFCs and HFAs
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Which are used today as a propellant in pMDIs?
HFAs
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have been identified as propellants that are nontoxic to the atmosphere and to the patient and that have properties suitable for MDI aerosol generation
HFAs
-
HFA stands for
hydrofluoroalkane
-
CFC stands for?
chlororfluorocarbon
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pMDIs can be divided into two categories:
conventional pMDIs and Breath-actuated pMDIs
-
the conventional pMDI has what kind of design?
press-and-breath desgn
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A type of device to simplify MDI use is
a breath-actuated adapter
-
inhalers offer an alternative for individuals who find it difficult to coordinate pMDI actuation with inhalation
breath- actuated
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Research on the drug content of sprays of albuterol by pMDI has shown that various factors affect
dose consistency
-
refers to the loss of drug content in the valve even though propellant may seem to discharge a normal dose.
Lose of dose
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The MDI should be ______ before the first actuation after standing, so that the metering valve refills with adequately mixed suspension from the canister
shaken
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Whsy shour the MDU be shaken?
There can be a seperation of suspensions when left standing.
-
A pause of ________ minutes has been advocated between each puff of a bronchodilator from an MDI, in an attempt to improve distribution of the inhaled drug in the lung
1-5
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refers to the loss of propellant from the metering valve of the MDI
Lose of prime
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Data indicate that dose delivery from CFC-propelled MDIs of albuterol decreases at lower temperatures. A significant decrease of 65% to 70% of the usual dose has been observed at
10oC
-
Aerosol drug delivery with a pMDI is dependent on
Nozle size, sleanliness, and lack of moisture
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The two primary techniques for using a pMDI without a spacer are:
The open mouth tech. and the closed mouth tech.
-
allows for slowing of the particle velocity and evaporation of aerosol droplets, resulting in less oropharyngeal impaction and loss
Spraying a few cm infront of the open mouth
-
Characteristics of the patient using the pMDI leads to a variability of
aerosol deposition
-
The most common error noted is the failure to coordinate
inhaltion w/ actuation
-
devices were introduced primarily to simplify the complex coordination of aiming, actuation, and breathing with a pMDI
Extentions or reservoirs
-
is similar to a pMDI except that the drug is in powdered form
DPI
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requires a high inspiratory flow rate from the patient to dispense the drug. The flow rate needed is usually 30 to 90 L/min
DPI
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DPIs can be divided into three categories based on the design of their dose containers:
unit-dose DPIs, multiple unit-dose DPIs, and multiple-dose DPIs
-
These DPIs have individually wrapped capsules that contain a single dose of medication and deliver powder medication from a punctured capsule
Unit-dose or single-dose
-
What is the lung depostition for MDI (CFC)?
8.8%
-
What is the lung depostition for MDI (HFA)?
52%
-
What is the lung depostition for MDI and Spacer (CFC)?
14.8%
-
What is the lung depostition for SVN?
12.4%
-
What is the lung depostition for DPI?
14.8-27.7%
-
The loss with an SVN is primarily in the delivery apparatus (66%), with most of that remaining in
the nebulizer
-
MDI loses about _____ in the actuator.
10%
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What is the dose of albuterol in MDI form?
2 puffs or 0.2 mg
-
what is the dose of albuterol in SCN?
0.5cc or 2.5mg
-
The ratio of MDI to SVN dose is approximately
1:12
-
-
-
how many drops in 5mL?
60
-
-
what are the two types of drug dose calulations that are generally made?
Those involving fluids, tabs., or caps, and thos involving sols. or a %.
-
contains a solute, which is dissolved in a solvent, giving a homogeneous mixture
solution
-
The strength of a solution is expressed as the percentage of solute relative to
total solvent and solute
-
means parts of the active ingredient (solute) in a preparation contained in 100 parts of the total preparation (solute and solvent).
percentage
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Nerve impulses are conducted by electrical and chemical means; the chemical portion of nerve transmission is referred to as a
neurotransmitter
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The neurotransmitter is __________ at the myoneural (neuromuscular) junction, at ganglia, and at parasympathetic end sites
acetylcholine
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The neurotransmitter at sympathetic end sites is generally __________ except at sweat glands and the adrenal medulla, where acetylcholine is the neurotransmitter
norepinephrine
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control is essential to life and is considered a more discrete, finely regulated system than sympathetic control. effects control the day-to-day bodily functions of digestion, bladder and rectal discharge, and basal secretion of bronchial mucus
Parasympathetic
-
verstimulation of the parasympathetic branch would render the body incapable of violent action, resulting in what is termed the SLUD syndrome:
Salvation, lacrimation, urination, and defecation
-
effects are widespread, mediated by norepinephrine at nerve endings and by circulating epinephrine released from the adrenal medulla.
Sympathetic
-
reacts as a general alarm system and does not exercise discrete controls. This is sometimes characterized as a �fight-or-flight� system
sympathetic
-
A nerve impulse signal is carried along a nerve fiber by
electrical action potentials
-
At gaps in the nerve fiber between neurons (synapses), the electrical transmission is replaced by a
chemical neurotransmitter
-
the chemical transmission of the electrical impulse, which occurs at the ganglionic synapses and at the end of the nerve fiber, termed the
neuroeffector site
-
The neurotransmitter conducting the nerve impulse at skeletal muscle sites is Ach, and this site is referred to as the
neuromuscular junction or myoneural junction
-
In the parasympathetic branch, the neurotransmitter is also Ach at both the ganglionic synapse and the terminal nerve site, referred to as the
neuroeffector site
-
The neurotransmitter acetylcholine is terminated by the enzyme
cholinesterase
-
neurotransmitter reuptake into the presynaptic neuron (uptake-1) and by the enzymes catechol O-methyltransferase (COMT) and monoamine oxidase (MAO) terminate what?
norepinephrine and sympathetic transmission
-
The autonomic system is generally considered an
effernt system
-
nerves run alongside the sympathetic and parasympathetic efferent fibers and carry impulses from the periphery to the cord
afferent
-
These terms are used for acetylcholine and norepinephrine/epinephrine receptors in the two autonomic branches.
cholinergic (cholinoceptor) and adrenergic (adrenoceptor)
-
Indirect-acting cholinergic agonists inhibit the
cholinesterase enzyme
-
stimulates autonomic muscarinic receptors in the iris sphincter and ciliary muscle of the eye to produce pupillary constriction (miosis) and lens thickening
echothiophate (Phospholine)
-
useful in increasing muscle strength in a neuromuscular disease such as myasthenia gravis, in which the cholinergic receptor is blocked by autoantibodies
Neostigmine and edrophonium
-
is used in the Tensilon test to determine whether muscle weakness is caused by overdosing with an indirect-acting cholinergic agent (causing ultimate receptor fatigue and blockade) or undertreatment with insufficient drug.
edrophonium
-
undesirable muscarinic effects can be blocked by pretreatment with a parasympatholytic or antimuscarinic drug such as
atropine
-
are used as insecticides, and occasionally patients are seen with toxic exposure and absorption
organophosphates
-
they have also been used as �nerve gas.� Because they affect Ach, they have an effect on neuromuscular function and muscarinic receptors; there is initial stimulation, then blockade if a high enough dosage is absorbed. Muscle weakness and paralysis can result.
parathion and malathion and the drug echothiophate
-
can be used in the treatment of organophosphate toxicity in the first 24 hours
pralidoxime chloride or cholinesterase reactivator
-
block Ach receptors and act as cholinergic antagonists
Anticholinergic agents
-
is usually considered the prototype parasympatholytic, and there is renewed interest in the use of aerosolized analogues
atropine
-
Atropine occurs naturally as the levo isomer in Atropa belladonna, the nightshade plant, and in Datura stramonium, or jimsonweed. The drug is referred to as a
belladonna alkaloid
-
Sympathetic effects on the cardiopulmonary system include
increased heart rate/contractile force, increased blood pressure, bronchodilation, and probable increased secretion from mucous glands in the airway
-
In the sympathetic branch of the autonomic nervous system, the usual neurotransmitter at the terminal nerve sites is
norepinephrine
-
In the presynaptic neuron, _______ is converted to dopa and then to dopamine, which is converted by dopamine �-hydroxylase to norepinephrine, in the storage vesicles.
Tryosine
-
The primary method of terminating the action of norepinephrine at the postsynaptic membrane is through a reuptake process, back into the presynaptic neuron. This is termed
uptake-1
-
Part of terminating norepinephrine. The neurotransmitter action can be ended by two other mechanisms as well: uptake into tissue sites around the nerve terminal, a process termed
uptake-2
-
norepinephrine can stimulate autoreceptors on the presynaptic neuron, which inhibits further neurotransmitter release. These autoreceptors have been identified as
alpha 2 - receptors
-
It is a mediated transport system, It is a low-affinity but high-capacity system, It is not as stereochemically specific, it is specific to catecholamines.
uptake-2
-
The order of affinity for uptake -2 is:
isoproterenol>epinephrine>norepinephrine
-
Chemicals structurally related to epinephrine are termed
catecholamines
-
Two enzymes are available that can inactivate catecholamines such as epinephrine:
catechol O-methyltransferase (COMT) and monoamine oxidase (MAO)
-
The action of both enzymes on epinephrine (Figure 5-6) is important because COMT is responsible for ending the action of
catecholamine bronchodilators.
-
The effects of adrenergic receptors are mediated by coupling with
G proteins
-
These are identified as G protein- linked recptors.
adrenergic recptors
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