Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pain Medicine > Chapter 19 Pharmacology for the Interventional Pain Physician > Flashcards

Chapter 19 Pharmacology for the Interventional Pain Physician Flashcards

1
Q

Iodinated contrast agents provide greater attenuation

of x-ray radiation, relative to

A

tissue and bone, reducing
the amount of radiation reaching the detector (fluoroscopic intensifier) This allows contrast to be easily visualized on x-ray images

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Iodinated contrast media (ICM)

in image-guided procedures is utilized to

A

define the anticipated spread and location of the injectate. This improves safety by avoiding injection of drugs into unintended locations such as intravascular or intrathecal
spaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

ICM are based on variations of

A

the 2, 4, 6 tri-iodinated benzene ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

ICM are classified on the basis of

A

their chemical structure, osmolality, iodine content, and ionization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The iodine content is responsible for

A

x-ray attenuation and the concentration in mg iodine/ml is used to express the strength of the
attenuation of a particular agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Clinically used ICM agents

have how much iodine

A

between 180 to 400 mg/ml of iodine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The chemical composition of contrast media is in four different forms:

A

ionic monomers,
ionic dimers,
nonionic monomers
nonionic dimers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Ionization of ICM is produced

by

A

substitutions on the benzene ring at the 1, 3, and 5 positions to produce water solubility and physiologic pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Solubility of the nonionic contrast media is due to

A

substitution with hydrophilic side chains such as

hydroxyl or amide groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The concentration of iodine necessary to obtain

radiographic attenuation dictates

A

the number of particles in solution (osmolality) needed for a particular agent to be effective

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Contrast osmotoxic reactions

A

pain on injection, hemolysis,
endothelial damage (capillary leak and edema), vasodilation
(flushing, warmth, hypotension, and cardiovascular
collapse), hypervolemia, and direct cardiodepressive effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Ionic ICM are strictly contraindicated for all applications involving the

A

central nervous system (CNS) and may cause severe or fatal neurotoxic reactions following
intrathecal administration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

ICM agents of choice for interventional pain procedures

A

Non-ionic ICM are the agents of choice due to their lower osmolality and toxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Commercially Available Ionic Monomeric X-ray Contrast Media

A 
Meglumine iothalamate (Conray)
Meglumine ioxithalamate (Telebrix)
Sodium amidotrizoate (Urografin, Hypaque)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Commercially Available Nonionic Monomers X-ray Contrast Media

A 
Iohexol (Omnipaque)
Iopentol( Imagopaque)
Ioxitol ( Ixilan)
Iomeprol (Iomeron)
Ioversol (Optiray)
Iopromide (Ultravist)
Iobitridol (Xenetix)
Iopamidol (Iopamiro)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Commercially Available Ionic Dimer X-ray Contrast Media

A

Ioxaglate (Hexabrix)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Commercially Available Non- Ionic Dimer X-ray Contrast Media

A

Iotrolan (Isovist)

Iodixanol (Visipaque)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

ICM Distribution

A

ICM are hydrophilic and demonstrate low protein binding. After intravascular injection there is rapid
distribution into the extracellular space and the fall in plasma concentration is rapid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

ICM Metabolism

A

Elimination is by glomerular filtration without reabsorption and there is virtually no metabolism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

ICM Elimination in patient with and without renal impairment.

A

In patients with normal renal function the elimination half-life is approximately 2 hr, and with renal impairment excretion can last for weeks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Severe reactions of ICM

A

anaphylactic or anaphylactoid symptoms of severe bronchospasm, laryngeal edema, angioedema, pulmonary edema, hypotension, convulsions, cardiac dysrhythmias, or arrest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Adverse reactions to ICM can be classified as

A

idiosyncratic or immediate and delayed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The immediate reactions of ICM

A

are generally the most severe and consist in this setting of
anaphylactoid type reactions of varying severity. These reactions are generally independent of dose and unpredictable, and usually occur within 1 hr of administration. There is increased risk in patients with a prior reaction to ICM, and with underlying disease including asthmatics,history of atopy, and advanced heart disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Treatment of immediate reactions of ICM

A

If suspected these reactions need to be treated with antihistamines,
epinephrine, corticosteroids, and full cardiopulmonary
resuscitation as needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Delayed reactions of ICM
Delayed reactions are composed of chemotoxic reactions and cutaneous manifestations of delayed hypersensitivity. The chemotoxic reactions include contrast mediated nephrotoxicity, decreased cardiac contractility, and neurotoxicity, all of which are dose dependent and should be rare in this setting with use of nonionized agents.
26
The delayed allergy-like skin reactions of ICM
are twice as frequent for nonionic dimers as for nonionic monomers
27
How to prevent adverse reactions of ICM?
The first step is to understand the risk factors, including a previous reaction to ICM, and take a history to elucidate the type of reaction the patient experienced. The history should also include the type of agent and whether it was an ionic or nonionic agent
28
Treatment protocols for anaphylactic and anaphylactoid reactions,
antihistamine and corticosteroid prophylaxis against anaphylactic and anaphylactoid reactions, including oxygen, intravenous fluids, antihistamines (H1 and H2blockers), adrenergic drugs (epinephrine), and corticosteroid
29
Ionic ICM vs. non-ioninc agents adverse reactions
Ionic ICM have 4 times the incidence of these reactions | compared to nonionic agents
30
Gadolinium containing | contrast agents
the use of gadolinium containing contrast agents beneficial as an alternative in high-risk patients. However, there is an upper limit to safe dosage of gadolinium (0.3 mmol/kg body weight)
31
Adverse Effects of Gadolinium containing contrast agents
caution and reduced dosage have to be taken in patients | with moderate to severe renal dysfunction due to its association with development of nephrogenic systemic fibrosis
32
Local anesthetics Mechanism of Action
LAs prevent generation and conduction of the nerve impulse by blocking voltage gated Na+ channels within the cell membrane. This reduces or prevents the transient increase in Na1+ permeability needed for depolarization and propagation of a nerve impulse.
33
Akyl substitutions on a LA increase
the lipid solubility
34
The potency of LAs have been shown to be directly related | to
lipophilicity and is often expressed as the octanol:water partition coefficient
35
Local anesthetics Acid or Base?
All LAs are weak acids as quaternary amines and are positively charged. As tertiary amines they are weak bases and uncharged
36
Local anesthetics be in what form to access their site of action on the Na+ channel?
They must be in their lipophilic base form | to access their site of action on the Na+ channel
37
pKa of the Local anesthetics
The pKa of the LA and pH at the site of injection (usually physiologic pH of 7.4 but can be locally altered, such as in areas of infection) influence the amount of LA in base form and the speed of block onset. In general, the lower the pKa of the LA the faster its the onset.
38
The addition of bicarbonate to a | solution does what to local anesthetics?
The addition of bicarbonate to a solution to increase the pH and speed of onset can be done to epinephrine-containing LAs that are adjusted to an acidic pH for stability
39
factors influencing the speed of onset include
the concentration and amount of LA used and the anatomic location of injection or application
40
Fibers response to local anesthetics
small unmyelinated C-fibers, autonomic fibers, and small myelinated Ad delta fibers (pain and temperature) are more sensitive than larger myelinated Ag, Ab, and Aa fibers (motor, proprioception, touch, and pressure.
41
Ropivacaine vs. Bupivacaine
More recently, ropivacaine, is stated | to be more motor sparing than bupivacaine and less cardiotoxicity at equipotent doses
42
multiple factors | that determine duration of action
Increased lipid solubility increases its duration of action. the rate of metabolism can be a factor (e.g., amino-ester LAs). the speed of uptake and/or elimination from the site of deposition, which is also dependent on tissue perfusion, influences the duration of action. addition of vasoconstrictors to decrease perfusion and uptake and thus prolong block
43
Perfusion of course is dependent on anatomic location
parauterine > intercostal >epidural > peripheral nerve >intrathecal
44
TABLE 19–2
Infiltration Anesthesia
45
most common adverse reactions of local anesthetic
The most common adverse reactions are autonomic responses or anticipatory reactions to medical procedures. These include tachycardia, sweating, hypotension, and syncope. They are characteristically short-lived with resolution in minutes requiring no treatment or can be treated with muscarinic blockers or ephedrine
46
common reaction is the response to vasoconstrictor | additives, usually epinephrine
Symptomatically this produces tachycardia, hypertension, and anxiety or feelings of doom. If injected peri- or intra-arterial it can produce distal ischemia from arterial spasm
47
systemic toxicity of local anesthetics results first in the CNS and then has cardiovascular effects
CNS symptoms consist of metallic taste, perioral numbness, dizziness, muscle twitching, and ultimately generalized seizures. Toxic cardiovascular effects include arrhythmias, cardiac depression, vasodilation, hypotension, and cardiac arrest/ collapse
48
Trearment of bupivacaine-induced cardiac toxicity
The use of 20% intralipid has been shown to be effective for resuscitation from bupivacaine-induced cardiac toxicity
49
Allergic reactions to LAs due to
The vast majority | of these are due to PABA from amino-ester LAs. Amino-amide LAs are exceedingly rare causes of allergic reactions
50
Paraben preservatives
Paraben preservatives are structurally very similar to PABA and can show allergic cross-reactivity to amino-ester LAs
51
The commonest allergic reactions of LA are
delayed (24 hrs to a week) minor cutaneous rashes. These are generally self-limited and treated with antihistamines and topical corticosteroids
52
allergic cross-reactivity to bisulfite preservatives in patients with
known food allergies and paraben preservatives in | patients with sulfa antibiotic allergY
53
A high level or complete | spinal block will result in
respiratory compromise by diaphragmatic and accessory muscle paralysis and in total sympathectomy
54
Treatment of High Spinal
Immediate resuscitation can be required, | including respiratory and cardiovascular support
55
Adverse Effects of Local Anesthetics
Intrathecal administration of some LAs (lidocaine, chloroprocaine) and additives (metabisulfite) are suspected of causing toxic effects ranging from transient neurologic symptoms (TNS) to adhesive arachnoiditis and permanent neurologic injury.
56
Naturally occurring corticosteroids are classified into three functional groups
mineralocorticoids, glucocorticoids, | and adrenal androgens.
57
corticosteroid | most commonly used for interventional pain procedures.
Glucocorticoids
58
mechanisms of action for corticosteroids
antiinflammatory effects, direct neural membrane stabilization, as well as modulation of peripheral nociceptor neurons and spinal cord dorsal horn cells
59
The anti-inflammatory effects of glucocorticoids are attributable to
their inhibition of inflammatory mediator production at both the local tissue and systemic immune response level
60
With any type of tissue trauma there is a release of inflammatory mediators including
arachidonic acid and its | metabolites (prostaglandins, leukotrienes), various cytokines (IL-1, IL-6, TNF-a), and other acute phase reactants
61
mechanisms of action for injected corticosteroids
inhibit the production of local inflammatory mediators, reduced spontaneous ectopic discharge rates seen following nerve injury, including in neuromas.. Reversible inhibition of nociceptive C-fiber transmission, but not A-B fiber transmission
62
glucocorticoid receptor sites within the dorsal horn
glucocorticoid receptor sites have been located on noradrenergic and 5-hydroxytryptamine neurons within the dorsal horn substantia gelatinosa—known pathways of pain transmission. This suggests that corticosteroids may modulate nociceptive input from peripheral nociceptors by a direct action on the spinal cord.
63
the anti-inflammatory efficacy and duration of activity are greater with
less soluble corticosteroid | preparations
64
major determinant of corticosteroid selection based upon
its duration of action (biological half-life) and antiinflammatory potency, but steroid particulate size relative to a red blood cell and aggregation is emerging as a major determinant of corticosteroid selection
65
An inadvertent injection of a steroid particulate into the artery of Adamkiewicz during thoracic or lumbar transforaminal epiduralsteroid injection could result in
spinal cord ischemia leading to profound lower extremity motor deficits, even paraplegia
66
complication of cervical level transforaminal | steroid injection
is infarction of the spinal cord or brain following injection of a particulate corticosteroid into a radicular artery or vertebral artery
67
Following systemic absorption, the vast majority of corticosteroid is reversibly bound to two plasma proteins: .
corticosteroid-binding globulin and albumin
68
the unbound and bound fraction of corticosteroid
the unbound fraction of corticosteroid is responsible for its cellular-mediated anti-inflammatory effects. The protein-bound corticosteroid undergoes sequential oxidative-reduction reactions yielding inactive compounds. This is followed by hepatic-mediated conjugation (sulfate or glucuronide), resulting in watersoluble metabolites that are renally excreted
69
adverse reactions following corticosteroid injection.
Sterile meningitis and arachnoiditis have been reported following intrathecal injection of methylprednisolone.Brief euphoric or manic reactions have been reported following high-dose conticosteroid therapy. analphylactoid reactions have been reported following intravenous, intramuscular, and soft-tissue conrticosteroid injections
70
Any type of anaphylactic reaction should be treated promptly and aggressively with
``` supportive therapies (i.e., airway, breathing, circulation, supplemental oxygen), including advanced cardiac life support guidelines when indicated ```
71
Potential Adverse Systemic Reactions Associated | with Corticosteroids
Fluid retention, Elevated blood pressure, Hyperglycemia, Generalized erythema/facial flushing Menstrual irregularities, Gastritis/peptic ulcer disease, Hypothalamic-pituitary-adrenal axis suppression, Cushing’s syndrome Bone demineralization Steroid myopathy Allergic reaction
72
aqueous-based or alcohol-based skin preparation solutions.
Aqueous-based iodophors, such as povidone-iodine, can be safely used on mucous membrane surfaces. Alcohol-based solutions offer a quicker onset and often more sustained antimicrobial activity.
73
The ideal preoperative skin antiseptic agent should
significantly reduce microbial counts on intact skin; be broad spectrum; be fast acting; have a persistent effect lasting for hours; and be nonirritating to the skin

Pain Medicine (76 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions