Studied by 2 people
WE PASSED THE LAST QUIZ (I think idk man she takes a whole week to grade them)
Cocaine
What was the first local anesthetic?
Lidocaine
Most used local anesthetic in dentistry?
Ideal
Qualities of an ____ Local Anesthetic
-Potent
-Reversible
-Absence of local and systemic rx’s
-Rapid onset
-Satisfactory duration
-Adequate tissue penetration
-Low cost
-Long shelf-life
-Sterilization by autoclave
-Ease of metabolism and excretion
Plasma
Esters are metabolized in the ____
Liver
Amides are metabolized in the ____
Aromatic
An LA molecule consists of
- ____ ring (nucleus) / Hydrophobic
-Intermediate chain (Hydrocarbon chain made of ester/amide)
-Amine group / Hydrophilic
-Esters have -CO-O- linkage
-Amides have -N-CO- linkage
Na+
Local anesthesia’s mechanism of actions works by:
-Blocking nerve conduction by inhibiting influx of ____ ions through ion-selective sodium channels which impairs action potential
Bases
Ionization factors:
-Local anesthesics are weak ____
-Anesthesia harder to attain with active infection
-Ionization equilibrium depends on PH and Pka
Toxicity
Absorption of LA:
-Systemic absorption Increases with inflammation
-Less absorption means less systemic ____
-Vasoconstrictors work to lessen the absorption rate
-Better lipid solubility leads to faster effect
-Able to cross BBB (Blood brain barrier) and placenta
Function
Order of loss of nerve ____
-Autonomic > Cold > Warmth > Pain, Touch > Pressure > Vibration > Proprioception > Motor
-Regained in reverse order
Hypotension
LA use as an Anti-arrhythmic
-Block cardiac Na channels → direct effect on cardiac muscle
-Can cause ____ (low blood pressure)
-Useful in IV form to TX arrhythmias
Toxicity
Highly vascular areas lead to faster systemic absorption and increased ____ risk
False
(True or False)
Topical anesthetic cannot cause toxicity
True
(True or False)
When administering LA through a syringe, it is best done in a slow and consistent manner
Metabolism
Adverse reactions can also depend on:
-Pt’s weight
-Rate of ____
-Excretion
Hyperthermia
Adverse Rx’s of LA:
-Toxicity: CNS and CV
-CNS stimulation before depression
-CV: MI, myocardial depression
-Local effects: Injection technique - physical injury, hematoma
-Malignant ____: Inherited generic cause - muscle rigidity, metabolic acidosis, high fever (TX using Dantrolene)
-Pregnancy: Use Lidocaine, smallest effective dose, ok for nursing mothers
Much greater
Allergic reactions with LA:
-Probably no allergic reactions to amides
-Ester have ____ ____ allergic potential
-Methylparaben is no onger used in dental cartridges
-LA with vasoconstrictor have sulfite as anti-oxidant → Acute asthmatic attack in sulfite sensitive individuals
-Sulfites do not have cross sensitivity with sulfa drugs (not same)
Salad Bar
____ ____ Syndrome caused by sulfite sprays on vegetables to keep them fresh for longer
-A person can develop a sulfite allergy at any point in their life
Sulfites
Composition of LA solutions
-Vasoconstrictor (Epinephrine)
-Antioxidant (Example: ____ )
-NaOH adjust pH (make closer to 6/7)
-NaCl (maintain isotonic solution)
-Methylparaben (preservative, not needed in single cartridge)
Amide
Examples of ____ Local Anesthetics (BLAMP)
-Bupivacaine: Prolonged duration (for post op pain) Do not give to patients prone to self-mutilation
-Lidocaine: Gold standard, topical available
-Articaine (Septocaine): High lipid solubility, thiophene derived, rapid metabolism, methemoglobinemia, low toxicity
-Mepivacaine (Carbocaine): Short procedures + Vasoconstrictor contraindicated
-Prilocain (Citanest): Gen. less potent and toxic, metabolized to ortho-toluidine → methemoglobinemia (TX w/ methylene blue) Contraindicated in patients with problems of oxygenation
Mutilation
-Bupivacaine: Prolonged duration (for post op pain) Do not give to patients prone to self-____
Standard
-Lidocaine: Gold ____, topical available
Thiophene
-Articaine (Septocaine): High lipid solubility, ____ derived, rapid metabolism, methemoglobinemia in high doses, low toxicity
Short
-Mepivacaine (Carbocaine): Used for ____ procedures + Vasoconstrictor contraindicated
Methylene
-Prilocain (Citanest): Gen. less potent and toxic, metabolized to ortho-toluidine → methemoglobinemia (TX w/ ____ blue) Contraindicated in patients with problems of oxygenation
Topically
Esters include:
-Procaine
-Tetracaine
Not used in cartridges, Benzocaine is used ______
Safest
Procaine / Novacaine
-PABA ester
-One of the ____ known LA, other LA measured against it
-Antiarrhythmic agent
-Not used in dentistry today
Dermatologic
Tetracaine / Pontocaine
-PABA ester
-Slow onset, long duration
-10x toxicity and potency of procaine
-____ reactions: Contact dermatitis, burning, stinging, angioedema
Dyclonine
This LA is neither an ester nor amide
-Used as a topical
Vasoconstrictors
Effects of ____:
-Prolong duration of action of LA
-Increase depth of anesthesia
-Delay systemic absorption
-Reduce systemic toxicity
-Reduce bleeding in area of injection (hemostasis)
Sympathomimetics
Vasoconstrictors are:
-Adrenergic agonists (another name is _____ )
-Contraindicated for pts with uncontrolled hypertension, angina pectoris, arrhythmias, MI, CVA (stroke) in past 6 months
-CARDIAC pt dose = .04 mg
-HEALTHY pt dose = .2 mg
TCA
Drug interactions with Epinephrine:
- ____: tri cyclic anti depressants increase BP
-Non selective beta blockers cause hypertension and reflex bradycardia
-Interactions with MAO and phenothiazines: not clinically significant
Onset, duration
Characteristics of LA and its effects:
-Lower pKa (closer to 7.4 pH, non-ionized form) → Faster onset, higher absorption
-Higher pKa (ionized form) → Slower onset
A balance of both forms is required:
-Non-ionized form to cross the nerve membrane.
-Ionized form to bind sodium channels and block nerve conduction.
-Higher protein binding → Longer duration of action
-Lower protein binding → Shorter duration of action
Ionization (pKa) affects ____, while protein binding affects ____
Naturally
Lipid solubility effects on LA:
-Lipid solubility affects potency and duration
(higher lipid solubility = higher potency and longer duration)
-if a drug is ____ highly lipid-soluble, it can still penetrate effectively even if its pKa is slightly higher
Benzocaine
What is the most used topical anesthetic?
-Is an ester
-Used in OTC products for teething, sunburn, insect bites, hemorrhoids
Lidocaine
What is the second most used topical anesthetic?
-Is an amide
Prilocaine
Injection-free LA: Oraqix
-Made up of Lidocaine and ____
-Onset: 30 sec
-Duration: 20 minutes
Side effects: Pain, soreness, irritation edema, redness, taste changes
Toxic
Cocaine
-Ester
-Potent and extremely ____
-Duration: 30 min
-Causes systemic absorption and CNS stimulation
-NO dental application
Cetacaine
Which of these topical anesthetics are NOT FDA approved?
-Benzocaine
-Lidocaine
-Cetacaine
-Oraqix
Sprays
Precautions with Topical
-Know relative toxicity
-Know drug concentration
-Use smallest volume
-Use lowest concentration
-Use least toxic drug
-Limit area of application with ____
Dose
Max safe ____ of LA
-Lidocaine : 500mg
-Mepivacaine : 400mg
-Prilocaine : 600mg
-Bupivacaine : 90mg
pg. 115 - table 10.3
Wells and Morton
These dentists recognized nitrous oxide and ether’s use
Hospital
____ operating room ideal setting for General Anesthesia (GA)
GABA
GA mechanism of action:
-CNS depressant
-Enhance ____ activity → Reduce action potential firing
-Hyperdepolarization reduces duration of opening of nicotinic receptor-activated cation channels
-Also makes it more difficult for K channels to activate
Induction
____ is the quick change of pt’s state of consciousness from
stage I to stage III
Major Surgery
4 Stages and planes of Anesthesia (Guedel)
-Stage I (Analgesia): Conscious and reflexes present, end of consciousness → Stage II
-Stage II (Delirium/excitement): Begins with unconsciousness, involuntary movement and excitement, emesis and incontinence, irregular respiration, tachycardia, mydriasis
-Stage III (Sugical anesthesia): Stage in which most ____ ____ is performed, has 4 planes, Adverse: HTN (Stage II), Resp. depression (Stage III), Respiratory arrest (Stage IV)
-Stage IV (Respiratory or medullary paralysis): If not reversed immediately, death will occur, max dilation of pupils, circulatory failure, cessation of all respiration, BP falls rapidly
Flagg
Modern anesthetic techniques: ____ Classification
-Induction: Preop meds and adjunctive drugs, all phases up to beginning of surgery
-Maintenence: Starts when depth of desired anesthesia is achieved and continues until completion of procedure
-Recovery: Begins with completion of surgery, includes post op period until pt is fully responsive
Inhalation
Classification of General Anesthetics by route of administration:
-____ Agents: Nitrous oxide, Sevoflurane, Isoflurane, Diethyl ether
-IV Agents: Barbiturates, Dissociative, Opioids, Benzodiazepines
Oxide
GA: types
-Induction Anesthesia
-Induction and maintenance anesthesia
-Nitrous ____
-Halogenated hydrocarbons
IV
Induction anesthesia
-Easier to control depth and duration of action
-Most given ___ except Ketamine (Ketamine can be IM as well)
-IV anesthesia uses: opioids, ultrashort-acting barbiturates, benzodiazepines
Necrosis
Ultrashort-acting Barbiturates
-Given IV, highly lipid soluble
-Rapid onset, 30-40 seconds
-Effective when combined with LA
-Complications: Extravascular or intraarterial injection- ischemia, ____, sloughing, laryngospasm, bronchospasm
-Contraindications: Absence of suitable veins, asthmaticus, porphyria, CV / renal impairment
Sedation
Etomidate- IV Anesthetic
-Short acting, rapid onset
-Used for conscious ____
-Metabolized in liver
-Safer CV profile
-Repeated dosing → adrenal suppression
Outpatient
Propofol - IV Anesthetic
-Onset: 30 sec
-Liver metabolized
-Low antiemetic effects
-Popular for ____ surgery
-Apnea 50-80% of cases
-Bradycardia, pain at injection site
Emergence Phenomena
Ketamine
-Chemically related to PCP (phencyclidine)
-Causes dissociative anesthesia
-Analgesia w/ out LOC (loss of consciousness)
-Can cause excessive salivation
-Drawback: ____ ____ - delirium / hallucination
-Contraindications: Hx of CV disease, high BP, psychiatric problems
Depression
Opioids
-Used as pre-anesthetic and during/post analgesia
-Does not significantly alter CV function
-Major disadvantage: Prolonged respiratory _____
-Egs: morphine, fentanyl, sufentanil, alfentanil
Benzodiazepines
Best adjunct agent for conscious sedation is?
Evaporate
Induction and maintenance anesthesia:
-Inhalation anesthetics: Chemically classified as halogenated hydrocarbons - fl, cl, br
-Gases and volatile liquids (easily ____)
-Most popular: Enflurane, Isoflurane
-Rarely: Halothane, methoxyflurane
Anesthesia
GA: Physical factors
-Depth of ____ based on tension or partial pressure of agent in brain
-Blood solubility expressed by blood gas partial coefficient
Low solubility → Fast in, fast out (Rapid onset and recovery)
eg. Sevoflurane, Desflurane, Nitrous Oxide
High solubility → Slow in, slow out (Slow onset, slow recovery)
eg. Halothane, Isoflurane
MAC = Minimum alveolar concentration: used to compare agents
-Definition: Min alevolar concentration of an anesthetic at 1 atmosphere required to prevent 50% of pt’s to response to surgical stimulus
Soluble
Nitrous Oxide facts
-Colorless gas
-Little/no odor
-Least ____ in blood out of all inhalation agents
-Anxiolytic, rapid onset
-Will cause light sedation
Diffusion Hypoxia
This condition may occur if there is rapid outflow of N2O along with O2 and CO2 (need at least 5 min on O2 for recovery)
Administration
Advantages of N2O
-Rapid onset (3-5 min)
-Easy ____, nose
-Allows close control and titration of levels
-Rapid recovery
-Acceptable for children
Green, blue
Color coded tanks for N2O:
-Oxygen is ____
-Nitrogen is ____
Respiratory obstruction
Main contraindication for N2O is any kind of ____ ____
Pregnant
N2O is safe for ____ pt’s and operators
-Spontaneous abortions higher with occupation exposure
-Reduced fertility if exposed over 5hrs/wk
Hydrocarbons
Halogenated ____ include:
-Halothane: Asthmatic safe, nonexpensive, cardiac arrhythmias
-Enflurane: Good analgesia, excessive motor activity,
-Isoflurane: Respiratory acidosis, low tissue solubility
-Desflurane/Sevoflurane: Newest, low tissue solubility
Halothane
What GA has these qualities?
-Fruity pleasant odor
-Asthmatic safe
-Non-expensive
-Non-flammable
-Cardiac arrhythmias
-Post anesthetic hepatitis
Enflurane
What GA has these qualities?
-Pleasant smell
-Good analgesia
-Excessive motor activity
-Transient renal function depression
Isoflurane
What GA has these qualities?
-Low tissue solubility
-Slightly pungent smell
-Reduce respiration and BP
-Respiratory acidosis with deeper anesthesia
Vaporizer
Desflurane and Sevoflurane
-Newest
-Rapid onset, shorter duration
-Desflurane needs a special ____
-Sevoflurane may be nephrotoxic
