p.17
Clinical Manifestations of Overdose
What symptoms might indicate a more severe local anesthetic overdose?
Drowsiness and disorientation.
p.2
Pharmacokinetics Overview
What is pharmacokinetics?
The study of the action of drugs within the body.
p.4
Absorption of Local Anesthetics
How are local anesthetics absorbed when administered orally?
With the exception of cocaine, local anesthetics are poorly absorbed from the gastrointestinal tract.
p.6
Distribution of Local Anesthetics
What is the elimination half-life of local anesthetics?
The rate at which local anesthetics are removed from the blood, or the time necessary for a 50% reduction in the blood level.
p.11
Excretion of Local Anesthetics
In what form does procaine primarily appear in the urine?
Procaine appears in the urine primarily as PABA (90%) with 2% unchanged.
p.7
Metabolism of Local Anesthetics
What does the toxicity of a local anesthetic depend on?
A balance between absorption and metabolism.
p.5
Absorption of Local Anesthetics
Which method of injection produces the most rapid elevation of blood levels of local anesthetics?
Intravenous (IV) injection.
p.10
Metabolism of Local Anesthetics
What is a primary metabolite of prilocaine and what condition can it cause?
Orthotoluidine, which can cause methemoglobinemia.
p.8
Metabolism of Local Anesthetics
What does procaine (an ester local anesthetic) undergo hydrolysis to?
p-aminobenzoic acid (PABA).
p.7
Metabolism of Local Anesthetics
What is metabolism in the context of local anesthetics?
The means by which the body transforms the active drug into an inactive form.
p.14
Systemic Actions of Local Anesthetics
What are the consequences of peripheral vasodilation caused by local anesthetics?
Peripheral vasodilation leads to blood vessel relaxation, increased blood flow, increased drug absorption, decreased depth and duration of local anesthetic action, increased bleeding, and increased local anesthetic blood levels.
p.2
Pharmacokinetics Overview
What are the four main actions included in pharmacokinetics?
Absorption, Distribution, Metabolism, Excretion.
p.5
Absorption of Local Anesthetics
What factors influence the rate of absorption of local anesthetics after injection?
The site vascularity and the vasoactivity of the drug.
p.14
Systemic Actions of Local Anesthetics
Which local anesthetic produces cutaneous vasoconstriction?
Ropivacaine produces cutaneous vasoconstriction.
p.13
Central Nervous System Effects
What is the pharmacologic action of local anesthetics on the CNS?
The pharmacologic action of local anesthetics on the CNS is depression.
p.12
Systemic Actions of Local Anesthetics
How does the blood level of local anesthetics affect their clinical action?
The higher the blood level, the greater the clinical action.
p.9
Metabolism of Local Anesthetics
Where does prilocaine primarily undergo metabolism?
In the liver, with some occurring in the lung.
p.10
Metabolism of Local Anesthetics
Do the metabolites of lidocaine produce sedation?
Yes, unlike lidocaine itself, its metabolites can produce sedation.
p.14
Systemic Actions of Local Anesthetics
What is the general effect of most local anesthetics on peripheral blood vessels?
Most local anesthetics produce peripheral vasodilation.
p.17
Clinical Manifestations of Overdose
What auditory disturbances might occur during a local anesthetic overdose?
Tinnitus (ringing in the ears).
p.13
Central Nervous System Effects
What are the CNS effects of local anesthetics at low (therapeutic, nontoxic) blood levels?
At low (therapeutic, nontoxic) blood levels, there are no significant CNS effects.
p.15
Systemic Actions of Local Anesthetics
What is the effect of a normal dose of local anesthetics on the respiratory system?
It has a direct relaxant action on bronchial smooth muscle.
p.9
Metabolism of Local Anesthetics
Which amide local anesthetics primarily undergo liver metabolism?
Lidocaine, mepivacaine, etidocaine, and bupivacaine.
p.8
Metabolism of Local Anesthetics
How are ester local anesthetics metabolized?
They are hydrolyzed in the plasma by the enzyme pseudocholinesterase.
p.14
Systemic Actions of Local Anesthetics
What effect does bupivacaine have on blood vessels?
Bupivacaine produces vasodilation.
p.6
Distribution of Local Anesthetics
Which organs initially have higher anesthetic blood levels due to high perfusion?
Brain, head, liver, kidneys, lungs, and spleen.
p.11
Excretion of Local Anesthetics
Is a proportion of local anesthetics excreted unchanged in the urine?
Yes, a proportion of local anesthetics is excreted unchanged in the urine.
p.14
Systemic Actions of Local Anesthetics
Which system is more resistant to the effects of local anesthetic drugs, the cardiovascular system or the central nervous system?
The cardiovascular system is more resistant than the central nervous system to the effects of local anesthetic drugs.
p.8
Metabolism of Local Anesthetics
What is the cause of allergic reactions that rarely occur in response to ester local anesthetics?
They are related to p-aminobenzoic acid (PABA).
p.3
Absorption of Local Anesthetics
What can increasing local anesthetic blood (plasma) concentration lead to?
Increasing local anesthetic blood (plasma) concentration can lead to overdose (toxic reaction).
p.13
Central Nervous System Effects
Do local anesthetics cross the blood-brain barrier?
Yes, local anesthetics cross the blood-brain barrier.
p.16
Clinical Manifestations of Overdose
What are some signs of minimal to moderate overdose levels of local anesthetics?
Talkativeness, apprehension, excitability, slurred speech, muscle twitching (face and extremities), euphoria, sweating, vomiting, elevated blood pressure, elevated heart rate, and elevated respiratory rate.
p.4
Absorption of Local Anesthetics
How are local anesthetics absorbed when applied topically?
Local anesthetics are absorbed at differing rates after application to mucous membranes.
p.11
Excretion of Local Anesthetics
What percentage of a cocaine dose is found unchanged in the urine?
10% of a cocaine dose is found unchanged in the urine.
p.17
Clinical Manifestations of Overdose
What are the initial symptoms of local anesthetic overdose?
Lightheadedness and dizziness.
p.3
Absorption of Local Anesthetics
Which local anesthetic produces vasoconstriction?
Cocaine produces vasoconstriction.
p.12
Systemic Actions of Local Anesthetics
What are most of the systemic actions of local anesthetics related to?
Their blood or plasma level in a target organ (CNS, CVS).
p.4
Absorption of Local Anesthetics
Which local anesthetics can produce surface anesthesia of intact skin?
Lidocaine and prilocaine (EMLA).
p.3
Absorption of Local Anesthetics
What effect do most local anesthetics (LA) have on blood vessels after injection?
Most local anesthetics produce dilation of the blood vessels after injection.
How can you distinguish amide local anesthetics from ester local anesthetics based on their names?
Amides contain a double 'i' in their names.
p.15
Systemic Actions of Local Anesthetics
What can an overdose of local anesthetics cause in the respiratory system?
It can produce respiratory arrest as a result of generalized CNS depression.
p.5
Absorption of Local Anesthetics
For what medical condition is intravenous injection of local anesthetics used?
Management of ventricular dysrhythmias.
p.8
Metabolism of Local Anesthetics
What represents a relative contraindication to ester local anesthetics?
Atypical pseudocholinesterase.
p.17
Clinical Manifestations of Overdose
What symptoms might follow lightheadedness and dizziness in a local anesthetic overdose?
Restlessness and nervousness.
p.16
Clinical Manifestations of Overdose
What are some signs of moderate to high overdose levels of local anesthetics?
Tonic-clonic seizure activity followed by generalized CNS depression, depressed blood pressure, heart rate, and respiratory rate.
p.11
Excretion of Local Anesthetics
Why do patients with renal impairment have an increased potential for toxicity from local anesthetics?
Because their ability to excrete local anesthetics and their metabolites is reduced.
What are some examples of esters of benzoic acid used as local anesthetics?
Butacaine, Cocaine, Benzocaine, Hexylcaine, Piperocaine, Tetracaine.
p.3
Absorption of Local Anesthetics
How does vasodilation affect the absorption of local anesthetics?
Vasodilation increases local anesthetic absorption into the blood, thus decreasing the duration and quality of pain control.
p.6
Distribution of Local Anesthetics
Why does skeletal muscle contain the greatest percentage of local anesthetics?
Because it is the largest mass of tissue, despite not being highly perfused.
p.9
Metabolism of Local Anesthetics
How is articaine metabolized?
Articaine is metabolized in the blood (primarily) and the liver due to its ester and amide components.
What are some examples of esters of p-aminobenzoic acid used as local anesthetics?
Chloroprocaine, Procaine, Propoxycaine.
p.10
Metabolism of Local Anesthetics
What factors can impair the biotransformation of amide local anesthetics?
Lower hepatic blood flow (hypotension, congestive heart failure) or poor liver function (cirrhosis).
p.13
Systemic Actions of Local Anesthetics
What effect does IV administration of local anesthetics have on pain threshold and analgesia?
IV administration of local anesthetics increases the pain threshold and produces analgesia.
p.14
Systemic Actions of Local Anesthetics
What effect does cocaine have on blood vessels at commonly used dosages?
Cocaine produces vasoconstriction at commonly used dosages.
p.3
Absorption of Local Anesthetics
Which local anesthetic is the most potent vasodilator?
Procaine is the most potent vasodilator.
p.13
Clinical Manifestations of Overdose
What can happen at higher (overdose, toxic) levels of local anesthetics?
At higher (overdose, toxic) levels, local anesthetics can cause generalized tonic-clonic convulsions.
What are some examples of amide local anesthetics?
Articaine, Bupivacaine, Dibucaine, Etidocaine, Lidocaine, Mepivacaine, Prilocaine, Ropivacaine.
