Chapter 10+11: Loc/Gen Anesthetics

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