This document provides information on local anesthesia. It defines local anesthesia and classifies local anesthetic agents into esters and amides. It describes the mechanism of action of local anesthetics in blocking nerve conduction and lists some commonly used local anesthetic agents like lidocaine, bupivacaine, and procaine. It also discusses vasoconstrictors that are often added to local anesthetics to prolong their duration of action and the composition, effects, administration and side effects of local anesthetic solutions.
Lecture slides for undergraduates medical (MBBS) Students. Source material for this presentation is Essentials of Pharmacology, KD Tripathi, Katzung and Goodman and Gillman. It deals with Local anaesthetics with their mechanism of action, pharmacokinetics , adverse effects and therapeutic uses.
Local anesthesia has been defined as loss of sensation in a circumscribed area of the body caused by depression of excitation in nerve endings or inhibition of the conduction process in peripheral nerves.
Classification
Mechanism of action
Duration of action
Absorption and distribution
Mode of action
Theories of action of L.A
Pharmacokinetics of local anaesthetics
Routes of administration
Metabolism or biotransformation
Individual agents
Vasoconstrictors
Systemic effects
Toxicity
Advantages
Disadvantages
Maximum allowable dose
Local anaesthetics in community trust services
Lecture slides for undergraduates medical (MBBS) Students. Source material for this presentation is Essentials of Pharmacology, KD Tripathi, Katzung and Goodman and Gillman. It deals with Local anaesthetics with their mechanism of action, pharmacokinetics , adverse effects and therapeutic uses.
Local anesthesia has been defined as loss of sensation in a circumscribed area of the body caused by depression of excitation in nerve endings or inhibition of the conduction process in peripheral nerves.
Classification
Mechanism of action
Duration of action
Absorption and distribution
Mode of action
Theories of action of L.A
Pharmacokinetics of local anaesthetics
Routes of administration
Metabolism or biotransformation
Individual agents
Vasoconstrictors
Systemic effects
Toxicity
Advantages
Disadvantages
Maximum allowable dose
Local anaesthetics in community trust services
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“Local Anaesthetics”
These are agents which upon topical application or local injection cause reversible loss of pain sensation in a restricted area of the body. They act by blocking both sensory and motor nerve conduction to produce temporary loss of sensation without loss of consciousness.
Mechanism of action
These drugs reversibly prevent the generation and propagation of impulses in all excitable membranes including nerve fiber by stabilizing the membrane.
Local anesthetics block the nerve conduction by decreasing the entry of Na+ during action potential. They interact with a receptor situated within the voltage sensitive Na+ channel and raise the threshold of Na+ channel opening.
Therefore, Na+ can’t enter into the cell in response to an impulse which prevents depolarisation. Thus, action potential is not generated.
This action affecting the depolarization which leads to failure of conduction of impulse without affecting the resting membrane potential (RMP) is known as membrane stabilizing effect.
History- Cocaine is a naturally occurring compound indigenous to the Andes Mountains, West Indies, and Java.
It was the first anesthetic to be discovered and is the only naturally occurring local anesthetic; all others are synthetically derived.
Cocaine was introduced into Europe in the 1800s following its isolation from coca beans. Sigmund Freud, the noted Austrian psychoanalyst, used cocaine on his patients and became addicted through self-experimentation.
In the latter half of the 1800s, interest in the drug became widespread, and many of cocaine's pharmacologic actions and adverse effects were elucidated during this time. In the 1880s, Koller introduced cocaine to the field of ophthalmology, and Hall introduced it to dentistry
Definition
General properties
Composition
Function of saliva
Formation of saliva
Method for collecting saliva
Advantages
Limitations
Analysis of saliva done for the diagnosis of systemic disease
Definition:
by Stedmann’s & Lipincott medical dictionary.
A clear, tasteless, odourless, slightly acidic (pH 6.8) viscous fluid, consisting of the secretion from the parotid, sublingual, submandibular salivary glands and the mucous glands of the oral cavity.
General properties
Volume: 1000 to 1500 mL of saliva is secreted per day and, it is approximately about 1 ml/ minute.
Contribution by each major salivary gland is:
i. Parotid glands: 25%
ii. Submandibular glands: 70%
iii. Sublingual glands: 5%.
Reaction: Mixed saliva from all the glands is slightly acidic with pH of 6.35 to 6.85.
Specific gravity: It ranges between 1.002 and 1.012.
Tonicity: Saliva is hypotonSalivary flow
The average person produces approximately 0.5 L – 1.5 L per day
Unstimulated Flow (resting salivary flow―no external stimulus)
Typically 0.2 mL – 0.3 mL per minute
Stimulated Flow (response to a stimulus, usually taste, chewing, or medication [eg, at mealtime])
Typically 1.5 mL – 2 mL per minute
INTRODUCTION
Tongue is a muscular organ
Situated in the floor of the mouth
FUNCTION
Taste
Speech
Mastication
Deglutition
EXTERNAL FEATURES
Tongue has
A Root
A tip
A body
ROOT
Is attached to the mandible and soft palate above and hyoid bone below.
These attachments prevent the swallowing of the tongue.
In between the 2 bones it is related to the geniohyoid and mylohyoid muscles.
TIP
Of the tongue forms the anterior free end which lies behind the upper incisor teeth.
BODY
Has
A curved upper surface or dorsum
An inferior or ventral surface MUSCLES OF THE TONGUE
Middle fibrous septum divides the tongue into right and left halves.
Intrinsic muscles
Superior longitudinal
Inferior longitudinal
Transverse
Vertical
Extrinsic muscles
Genioglossus
Hyoglossus
Styloglossus
Palatoglossus
Central face begins to develop by 4th week, when olfactory placodes appear on both sides of the frontonasal process.
Gradually both placodes develop to form the median and lateral nasal process.
Upper lip is formed by 6th week by fusion of two median nasal processes in midline and the maxilllary process of the 1st branchial arch.
PRE-NATAL GROWTH AND DEVELOPMENT OF PALATEFormation of primary and secondary palate
Elevation of palatal shelves
Fusion of palatal shelves
Introduction
Epidemiology
Etiology
Manifestations
TNM staging
Squamous cell carcinoma is defined as malignant epithelial neoplasm exhibiting squamous differentiation as characterised by the formation of keratin and/or the presence of intercellular bridges.
( Pindborg et al, 1997).
Occipital (2-4)
Superior nuchal line between sternocleidomastoid and trapezius
Occipital part of scalp
Superficial cervical lymph nodes
Accessary lymph nodes
Mastoid (1-3)
Superficial to sternocleidomastoid insertion
Posterior parietal scalp
Skin of ear, posterior external acoustic meatus
Superior deep cervical nodes Accessary lymph nodes
Preauricular (2-3)
Anterior to ear over parotid fascia
Drains areas supplied by superficial temporal artery
Anterior parietal scalp
Anterior surface of ear
Superior deep cervical lymph nodes
Parotid (up to 10 or more)
About parotid gland and under parotid fascia
Deep to parotid gland
External acoustic meatus
Skin of frontal and temporal regions
Eyelids, tympanic cavity
Cheek, nose (posterior palate)
Superior deep cervical lymph nodes
Facial
Superficial(up to 12)
Maxillary
Buccal
Mandibular
Distributed along course of facial artery and vein
Skin and mucous membranes of eyelids, nose, cheek
Submandibular nodes
Deep
Distributed along course of maxillary artery lateral to lateral pterygoid muscle
Temporal and infratemporal fossa
Nasal pharynx
Superior deep cervical lymph nodesSuperficial
Anterior jugular vein between superficial cervical fascia and infrahyoid fascia
Skin, muscles, and viscera of infrahyoid region of neck
Superior deep cervical lymph nodes
Deep
Between viscera of neck and investing layer of deep cervical fascia
Adjoining parts of trachea, larynx, thyroid gland
Superior deep cervical lymph nodes
Anterior cervical/Superficial
Submental (2-3)
Submental triangle
Chin
Medial part of lower lip
Lower incisor teeth and gingiva
Tip of tongue
Cheeks
Submandibular lymph node to jugulo-omohyoid lymph node and superior deep cervical lymph nodes
Is a phenomenon of reflex sequence of muscle contractions that propels the ingested materials and pooled saliva from the mouth to the stomach.
PATTERNS
Infantile (visceral) swallow
Adult/mature swallow
ADULT SWALLOWING
Is composed of 4 stages
Voluntary
Preparatory phase
Oral or buccal
Involuntary: Controlled By Medulla and Lower Pons
Pharyngeal
b. Oesophageal
• Function
• External features
• Papillae of tongue
• Muscles of the tongue
• Arterial supply
• Venous drainage
• Lymphatic drainage
• Nerve supply
• Histology
• Development of tongue -
Intrinsic muscles
Superior longitudinal
Inferior longitudinal
Transverse
Vertical
- Extrinsic muscles
Genioglossus
Hyoglossus
Styloglossus
Palatoglossus
1. Vallate or circumvallate papillae
These are large in size 1-2mm in diameter and are 8-12 in number.
They are situated immediately in front of the sulcus terminalis.
Each papillae are cylindrical projection surrounded by a circular sulcus.
The walls of the papilla are raised above the surface.
2. Fungiform papillae
Are numerous
Near the tip and margins of the tongue, but some of them are scattered over the dorsum.
These are smaller than the vallate papillae but larger than the filliform papillae.
Each papilla consists of a narrow pedicle and a large rounded head.
They are distinguished by their bright red colour.
3. Filliform papillae
Conical papilla
Cover the presulcal area of the dorsum of the tongue and gives it a characteristic velvety appearance.
They are the smallest and most numerous of the lingual papillae.
Each are pointed and covered with keratin
The apex is often split into filamentous processes.
Fifth cranial nerve
Have a large sensory root and a small motor root.
Motor root arises – arises from the lateral aspect of lower pons (cranially) the motor root cross the apex of the petrous temporal bone beneath the superior petrosal sinus, to enter the middle cranial fossa.
Sensory root – arises from the lateral aspect of lower pons (caudally).
RELATIONS
Medially
(a) internal carotid artery
(b) posterior part of cavernous sinus
Laterally - middle meningeal artery
Superiorly - parahippocampal gyrus
Inferiorly
motor root of trigeminal nerve
(b) greater petrosal nerve
(c) apex of the petrous temporal bone
(d) foramen lacerum.OPTHALIMIC DIVISION
Terminal branches of Ophthalmic division of trigeminal nerve, are
1. Frontal
Supratrochlear
Supraorbital
2. Nasociliary
Branch of ciliray ganglion
2-3 long ciliary nerves
Posterior ethmoidal
Infratrochlear
Anterior ethmoidal
3. Lacrimal
Branches
From main trunk
Meningeal branch
Nerve to medial pterygoid
From the anterior trunk
Sensory branch
Buccal nerve
Motor branch
Masseteric
Deep temporal nerve
Nerve to lateral pterygoid
From the posterior trunk
Auriculotemporal
Lingual
Inferior alveolar nerves
COTTON-WOOL APPEARANCE
Active phase showing disorganised bone architecture with numerous, large, multinucleated osteoclasts. The stroma is vascular and fibrous
The late phase features thick trabeculae with a prominent mosaic pattern of prominent, hematoxyphilic, cement lines at the interfaces of episodes of resorption followed by deposition.
Paget disease showing very prominent blue cement lines. The lamellae are arranged haphazardly giving an overall effect of a jigsaw puzzle.
Hume- “caries is essentially a progressive loss by acid dissolution of the apatite component of the enamel then the dentin or of the cementum then dentin.”
According to location:
Pit or Fissure caries
Smooth Surface caries
According to rapidity:
Acute
Chronic
Arrested
According to occurrence:
Primary (Virgin) caries
Secondary (Recurrent) caries
According to the site of occurrence:
Enamel caries
Cemental caries.
Acidogenic [ Miller’s Chemico-parasitic] theory.
Proteolytic theory.
Proteolysis- chelation theory.
The lymphatic system has three functions:
Fluid recovery.
Immunity
Lipid absorption
The lymphatic vessels of the small intestine receive the special designation of lacteals or chyliferous vessels.
The components of the lymphatic system are :-
lymph, the recovered fluid;
Lymphatic vessels, which transport the lymph;
Lymphatic tissue, composed of aggregates of lymphocytes and macrophages that populate many organs of the body; and
Lymphatic organs, in which these cells are especially concentrated and which are set off from surrounding organs by connective tissue capsules.
A Magnified Microscopic Image Is Worth More Than A Thousand Words.
DARK FIELD MICROSCOPE
PHASE CONTRAST MICROSCOPY
POLARIZED LIGHT MICROSCOPY
FLUORESCENT MICROSCOPY
STEREO MICROSCOPE
ELECTRON MICROSCOPY
Maxillary Second Premolar
the maxillary first premolar in function
Less angular ,rounded crown in all aspects.
Single root
Smaller crown cervico occlusally
Root length is as great or greater
BUCCAL ASPECT
Not as long as that of the first premolar
Less pointed
Mesial slope is
shorter than the distal slope
Buccal ridge of the crown may not be so prominent whencompared with the first premolarLINGUAL ASPECT
Lingual cusp is longer making the crown longer on the lingual sideMESIAL ASPECT
Cusps of second premolar are shorter with the buccal and lingual cusps more nearly the same length
Greater distance between cusp tips-that widens the occlusal surface buccolingually
No developmental depression on the mesial surface of the crown as on the first premolar
Crown surface is convex instead
No deep dev. Groove crossing the mesial marginal ridgeOCCLUSAL ASPECT
Outline of the crown is more rounded or oval rather than angular
Central dev. groove is shorter and more irregular
Tendency toward multiple supplementary grooves radiating from the central groove that may extend out to the cusp ridges
Makes for an irregular occlusal surface and gives a very wrinkled appearance
Centered in the maxilla, one on either side of median line, with mesial surface of each in contact with mesial surface of other
Two in number
Larger than the lateral incisor
These teeth supplement each other in function, and they are similar anatomically
Shearing or cutting teeth
Major function is to punch and cut food material during the process of mastication
These teeth have incisal ridges or edges rather than
cusps such as are found on canines & posterior teeth
First evidence of calcification
Crown completion
Eruption
Root completion
3-4 months
4-5 years
7-8 years
10-11 years
PHYSICAL PROPERTIES
CHEMICAL PROPERTIES
STRUCTURE OF ENAMEL
DEVELOPMENT OF ENAMEL
EPITHELIAL ENAMEL ORGAN
AMELOGENESIS
LIFE CYCLE OF AMELOBLASTS
AGE CHANGES IN ENAMEL
DEFECTS OF AMELOGENESIS
CLINICAL IMPLICATIONS
PRENATAL GROWTH OF MANDIBLE
Occurs between the 4th and 7th week of intrauterine life.
4th week of intrauterine life
Formation of the head fold
Following which the developing brain and the pericardium form 2 prominent bulges on the ventral aspect of the embryo.
The 2 bulges are separated from each other by a shallow depression called stomatoedum (corresponding to the primitive mouth).
Floor of the stomatodeum is formed by the Buccopharyngeal membrane, which separates the stomatodeum from the foregut.Soon, mesoderm covering the developing forebrain proliferates, and forms a downward projection that overlaps the upper part of the stomatodeum – this downward projection is called frontonasal process.
Since the formation of various parts of the face involves fusion of diverse components.
Occasionally this fusion can be incomplete give rise to various anomalies
MANDIBULOFACIAL DYSOSTOSIS OR FIRST ARCH SYNDROME
- Entire first arch may remain underdeveloped on one or both sides, affecting
Lower eyelid
Maxilla
Mandible
External ear.
- Prominence of the cheek is absent
- Ear is displaced ventrally and caudally
Face develops in humans between 4th – 10th week of intrauterine life.
prenatal growth of the maxilla
DEVELOPMENT OF UPPER LIP
Development of lower lip
Development of nose
hare lip
OBLIQUE FACIAL CLEFT
macrostomia
lateral facial cleft
microstomia
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
3. DEFINITION:
IT IS THE LOSS OF SENSATION IN A
CIRCUMSCRIBED AREA OF THE BODY
CAUSED BY A DEPRESSION OF
EXCITATION IN NERVE ENDINGS OR
AN INHIBITION OF THE
CONDUCTION PROCESS IN
PERIPHERAL NERVES
5. Esters vs Amides
The ester linkage is more easily broken so the ester drugs are less
stable in solution and cannot be stored for as long as amides.
Amide anaesthetics are also heat-stable.
The metabolism of most esters results in the production of para-
aminobenzoate (PABA) which is associated with allergic reaction.
Amides, in contrast, very rarely cause allergic phenomena. For these
reasons amides are now more commonly used than esters.
6. BASED ON MODE OF APPLICATION
INJECTABLE
LOW POTENCY, SHORT
DURATION
PROCAINE
INTERMEDIATE POTENCY
AND DURATION
LIGNOCAINE (LIDOCAINE)
HIGH POTENCY, LONG
DURATION
TETRACAINE, BUPIVACAINE,
ROPIVACAINE, DIBUCAINE
SURFACE/TOPICAL
SOLUBLE
COCAINE, LIGNOCAINE,
TETRACAINE, BENOXINATE
INSOLUBLE
BENZOCAINE,
BUTYLAMINOBENZOATE
(BUTAMBEN)
7. BASED ON DURATION
ULTRA SHORT ACTING (<30 MINUTES)
PROCAINE WITHOUT VASOCONSTRICTOR
2% LIDOCAINE WITHOUT VASOCONSTRICTOR
SHORT ACTING (45-75 MINUTES)
2% LIDOCAINE WITH 1:100,000 EPINEPHRINE
4% PRILOCAINE WHEN USED FOR NERVE BLOCK
MEDIUM ACTING (90-150 MINUTES)
2% LIDOCAINE + 2% MEPIVACAINE WITH A VASOCONSTRICTOR
4% PRILOCAINE WITH 1:200,000 EPINEPHRINE
LONG ACTING (180 MINUTES OR LONGER)
0.5% BUPIVACAINE 1:200,000 EPINEPHRINE
8. ACCORDING TO BIOLOGICAL SITE AND
MODE OF ACTION
CLASS A AT RECEPTOR SITE
ON EXTERNAL
SURFACE OF NERVE
MEMBRANE
BIOTOXIN
TETRODOTOXIN
CLASS B AT RECEPTOR SITE
ON INTERNAL
SURFACE OF NERVE
MEMBRANE
QUATERNARY
AMMONIUM
ANALOGUES OF
LIDOCAINE
SCORPION VENOM
CLASS C BY A RECEPTOR
INDEPENDENT
PHYSICOCHEMICAL
MECHANISM
BENZOCAINE
CLASS D BY COMBINATION
OF RECEPTOR AND
RECEPTOR
CLINICALLY USEFUL
LOCAL ANESTHETIC
AGENTS
9. MECHANISM OF ACTION
ALTERING THE RESTING POTENTIAL OF THE NERVE
MEMBRANE
ALTERING THE THRESHOLD POTENTIAL (FIRING LEVEL)
DECREASING THE RATE OF DEPOLARIZATION
PROLONGING THE RATE OF REPOLARIZATION
10.
11. Effect of PH
Local anesthetics are weak bases and are usually formulated as the
hydrochloride salt to render them water-soluble.
At the chemical's pKa the protonated (ionized) and unprotonated
(unionized) forms of the molecule exist in an equilibrium but only the
unprotonated molecule diffuses readily across cell membranes.
Once inside the cell the local anesthetic will be in equilibrium, with the
formation of the protonated (ionized form), which does not readily pass
back out of the cell. This is referred to as "ion-trapping".
12. Effect of PH
LA are weak bases and their activity increases by increasing PH
This because if large amount of a drug is unpolar, it will facilitate its
penetration through the cell membrane
Once the drug has penetrated the lipid barrier and reach its site of action it
ionized and the ionized form is responsible for LA activity
13. Acidosis such as caused by inflammation at a wound partly reduces
the action of local anesthetics.
This is partly because most of the anesthetic is ionized and therefore
unable to cross the cell membrane to reach its cytoplasmic-facing
site of action on the sodium channel.
14. Local anesthetics block conduction in the following order: small
myelinated axons (e.g. those carrying nociceptive impulses), non-
myelinated axons, then large myelinated axons. Thus, a differential
block can be achieved (i.e. pain sensation is blocked more readily
than other sensory modalities).
15. Disruption of ion channel function via
specific binding to sodium channels,
holding them in an inactive state.
Disruption of ion channel function by
the incorporation of local anaesthetic
molecules into the cell membrane .
16. Small nerve fibres are more sensitive than large nerve fibres
Myelinated fibres are blocked before non-myelinated fibres of the same
diameter.
Thus the loss of nerve function proceeds as loss of pain, temperature,
touch, proprioception, and then skeletal muscle tone. This is why people
may still feel touch but not pain when using local anaesthesia.
17. THEORIES
THE ACETYLCHOLINE THEORY
THE CALCIUM DISPLACEMENT THEORY
THE SURFACE CHARGE THEORY
THE MEMBRANE EXPANSION THEORY
THE SPECIFIC RECEPTOR THEORY
18. CALCIUM IONS DISPLACED FROM SODIUM
CHANNEL RECEPTOR SITE
↓
LOCAL ANESTHETIC MOLECULE BINDS TO THIS
SITE
↓
BLOCKADE OF SODIUM CHANNEL
↓
DECREASE IN SODIUM CONDUCTION
↓
DEPRESSION OF RATE OF ELECTRICAL
DEPOLARIZATION
↓
FAILURE TO ACHIEVE THRESHOLD POTENTIAL
↓
LACK OF DEVELOPMENT OF ACTION POTENTIAL
↓
CONDUCTION BLOCKADE
MEMBRANE EXPANSION THEORY
SPECIFIC RECEPTOR
THEORY
19. The duration of action
The duration of action of the drug is also related to the length of the
intermediate chain joining the aromatic and amine groups.
Protein binding , Procaine is only 6% protein bound and has a very
short duration of action, wherease bupivacaine is 95% protein
bound. bupivacaine have a longer duration of action .
20. Absorption and distribution
Some of the drug will be absorbed into the systemic circulation: how
much will depend on the vascularity of the area to which the drug has
been applied.
The distribution of the drug is influenced by the degree of tissue and
plasma protein binding of the drug. the more protein bound the agent,
the longer the duration of action as free drug is more slowly made
available for metabolism.
21. Metabolism and excretion
Esters (except cocaine) are broken down rapidly by plasma esterases
to inactive compounds and consequently have a short half life.
Cocaine is hydrolysed in the liver. Ester metabolite excretion is renal.
Amides are metabolised hepatically by amidases. This is a slower
process, hence their half-life is longer and they can accumulate if
given in repeated doses or by infusion.
22. Adverse Effects
CNS: excitation followed by depression (drowsiness to
unconsciousness and death due to respiratory depression.
Cardiovascular System: bradycardia, heart block, vasodilation
(hypotension)
Allergic reactions: allergic dermatitis to anaphylaxis (rare, but
occur most often by ester-type drugs).
23. COMPOSITION OF LOCAL ANESTHETIC
AGENT
LIGNOCAINE 2%
VASOCONSTRICTOR- ADRENALIN
SODIUM META BISULPHITE 0.5mg (ANTIOXIDENT)
METHYL PARABEN (PRESERVATION)
THYMOL (ANTIFUNGAL)
WATER (TO MAINTAIN VOLUME)
NaCl (ISOTONICITY)
PHENTOLAMINE (REVERSING AGENT)
INSTEAD OF METHYL PARABEN- CAPRYL
HYDROCAPRINO TOXIN
24. LOCAL ANESTHETIC AGENTS
ESTER DERIVATIVES
PROCAINE
DIETHYLAMINOETHYL ESTER OF PABA BY
EINHORN IN 1905
AVAILABLE AS 4% SOLUTION
ALSO AVAILABLE IN 2% SOLUTION IN
COMBINATION WITH 0.4% PROPOXYCAINE AND
1:30,000 LEVARTERENOL OR 1:20,000
LEVONORDEFRIN
25. PROCAINE IS A WHITE CRYSTALLINE POWDER
SLIGHTLY SOLUBLE IN WATER
MOST COMMONLY USED AS HYDROCHLORIDE
SALT
PROCAINE IS COMPARATIVELY WEAK
ANESTHETIC
LOW DEGREE OF TOXICITY
STANDARD OF TOXICITY AND POTENCY
ASSIGNED A POTENCY AND TOXICITY OF 1
PROFOUND VASODILATOR
0.5 TO 1 gm SLOWLY OVER SUFFICIENT PERIOD
26. • PROCAINE IS HYDROLYZED TO PABA AND
DIETHYLAMINOETHANOL WITHIN THE PLASMA
• ONSET OF ANALGESIA DEPENDS ON THE
CONCENTRATION AND METHOD EMPLOYED
• WHEN INFILTRATED AROUND FREE NERVE
ENDINGS ONSET IS ALMOST IMMEDIATE
• PULPAL ANALGESIA IS ABOUT 30 MINUTES
27. NERVOUS SYSTEM:
READILY CROSSES THE BLOOD BRAIN BARRIER
PRODUCES BOTH STIMULATION AND DEPRESSION OF CNS
CVS:
DEPENDS MAINLY ON THE AMOUNT OF DRUG USED
SYSTEMICALLY DEPRESSES SMOOTH, CARDIAC AND SKELETAL
MUSCLES
EFFECT ON HEART IS QUINIDINE LIKE
IN LARGE DOSES MAY PRODUCE HYPOTENSION
RESPIRATORY SYSTEM:
LOCAL ANESTHETIC DOSE HAS LITTLE DIRECT EFFECT
29. • RAPIDLY DECOMPOSED BY ALKALI
• pKa 8.5
• COMPATIBLE WITH SULFONAMIDES AND ALL
VASOCONSTRICTORS
• AVAILABLE IN 0.15%, 1% AND 2% TOPICAL ONLY
• POPULAR FOR SPINAL ANESTHESIA
• BIOTRANSFORMATION IN THE LIVER AND END
PRODUCTS ELIMINATED BY THE KIDNEYS
• CHEMICALLY RELATED TO PROCAINE BUT
PHARMACOLOGICALLY CLOSER TO COCAINE
30. POTENT TOPICAL ANESTHETIC WITH NO
SIGNIFICANT VASODILATION PROPERTY
WHEN INJECTED WITHOUT A VASOCONSTRICTOR
PRODUCES 30 TO 45 MINUTES OF ANALGESIA
SAME CONCENTRATION WITH 1:100,000
EPINEPHRINE PRODUCES 75 TO 120 MINUTES OF
ANALGESIA
MAXIMUM DOSE: 20mg (1ml OF 2% SOLUTION)
NON IRRITATING
CNS AND CVS EFFECTS ARE SIMILAR TO THOSE OF
PROCAINE
32. • ELIMINATED BY KIDNEYS
• RAPID ONSET
• PROFOUND ANESTHESIA OF LONG DURATION
WHEN INJECTED CLOSE TO THE NERVE
SHEATH
• MAXIMUM DOSE 6.6 mg/Kg (3mg/ Ib)
• MAXIMUM TOTAL ANESTHETIC DOSAGE
SHOULD NOT EXCEED 400 mg
33. 2-CHLORPROCAINE
BETA-DIETHYLAMINOETHYL-2-CHLORO-4-
AMINOBENZOATE
pH 4.8
THE SUBSTITUTION OF A CHLORIDE ATOM IN
THE BENZENE RING OF PROCAINE CAUSES A
FOURFOLD IN THE HYDROLYSIS RATE
MORE POTENT AND LESS TOXIC THAN
PROCAINE
RAPIDLY HYDROLYZED IN THE PRESENCE OF
PLASMA CHOLINESTERASE
34. • BYPRODUCTS ELIMINATED THROUGH KIDNEYS
• 1.2% OR 3% CONCENTRATION IS USED
• NON IRRITATING TO TISSUE
• SHORT DURATION, IT MUST BE USED WITH
VASOCONSTRICTOR
• USED IN CHILDREN
• MAXIMUM DOSE: 11mg/Kg OR 800mg (40ml OF
3% SOLUTION)
35. LIDOCAINE
IN 1943 BY LOFGREN
IT IS THE FIRST NON ESTER TYPE OF LOCAL
ANESTHETIC
LIDOCAINE BASE IS ONLY SLIGHTLY WATER
SOLUBLE, THE HYDROCHLORIDE SALT IS READILY
SOLUBLE IN WATER
IS THE STANDARD OF COMPARISION
DIFFUSES READILY THROUGH INTERSTITIAL TISSUE
AND IN TO THE LIPID RICH NERVE
36. RAPID ONSET OF ANESTHESIA
pKa 7.85 FAVORS DEPROTONIZATION AND
PRODUCES UNIONIZED FREE BASE AND
PRODUCTION OF CONDUCTION BLOCK
2 TIMES AS POTENT AND TOXIC AS PROCAINE
ONSET TIME IS OF ABOUT 2 TO 3 MINUTES
DURATION OF ACTION DEPENDS ON TYPE OF
INJECTION AND AMOUNT OF
VASOCONSTRICTOR
37. NERVOUS SYSTEM:
IN TOXIC DOSES FIRST PRODUCES STIMULATION AND THEN
DEPRESSION OF CNS
IV LIDOCAINE IS CAPABLE OF PRODUCING A DEGREE OF
ANALGESIA AND GENERAL ANESTHESIA
CVS:
50 TO 100 mg (1.5 mg/Kg) GIVEN IV DURING GENERAL ANESTHESIA
AND SURGERY TO CORRECT VENTRICULAR ARRHYTHMIAS
TOXIC DOSE : HYPOTENSION AND CARDIOVASCULAR COLLAPSE
RESPIRATORY SYSTEM:
SMALL DOSE HAS A MILD BRONCHODILATING EFFECT
RESPIRATORY ARREST IS THE MOST COMMON CAUSE OF DEATH
RELATED TO OVER DOSE
38. LIDOCAINE UNDERGOES BIOTRANSFORMATION
IN THE LIVER RATHER THAN HYDROLYSIS IN
THE PLASMA
LIDOCAINE AND ITS BYPRODUCTS ARE
ELIMINATED BY THE KIDNEYS
4-HYDROXY-2,6-DIMETHYLANILNINE IS THE
MAJOR URINIARY METABOLITE
MAXIMUM DOSE: 4.4 mg/Kg (2mg/lb)
39. • NOT TO EXCEED 300mg WHEN NOT USED WITH
A VASOCONSTRICTOR
• 7mg/Kg (3.2 mg/lb)
• NOT TO EXCEED 500mg WHEN USED WITH
EITHER 1:50,000 OR 1:100,000 EPINEPHRINE
• DENTAL CARTRIDGES OF 2% LIDOCAINE ARE
AVAILABLE AND CONTAIN NO
VASOCONSTRICTOR OR EPINEPHRINE IN
CONCENTRATIONS OF 1:100,000 OR 1:50,000
40. MEPIVACAINE
MOLECULAR WEIGHT 285.5
WITHOUT A VASOCONSTRICTOR PULPAL
ANALGESIA OF 20 TO 40 MINUTES
MODERATELY LONG DURATION OF ACTION
2 TIMES AS POTENT AND TOXIC AS PROCAINE
CURRENTLY MEPIVACAINE (COOK-WAITE
LABORATORIES), LIDOCAINE AND PRILOCAINE
(ASTRA PHARMACEUTICALS) ARE THE ONLY
DENTAL CARTRIDGES THAT DO NOT CONTAIN THE
GERMICIDE OR PRESERVATIVE METHYL PARABEN,
WHICH HAS BEEN IMPLICATED AS THE CAUSATIVE
AGENT IN MANY ALLERGIC REACTIONS
41. IT IS A PABA DERVATIVE
MAY ALSO BE RESPONSIBLE FOR CROSS
SENSITIVITY BETWEEN ESTER AND NON
ESTER ANESTHETIC AGENTS
MAXIMU DOSE: WITH OR WITHOUT A
VASOCONSTRICTOR IS 6.6mg/Kg (3mg/lb)
NOT TO EXCEED 400mg
AVAILABLE IN 3% CONCENTRATION
WITHOUT VASOCONSTRICTOR OR A 2%
SOLUTION WITH 1:20,000 LEVONORDEFRIN
42. PRILOCAINE
DERIVATIVE OF TOLUIDINE INSTEAD OF XYLIDINE
EMPIRICAL FORMULA OF BASE : C13H20N20
MOLECULAR WEIGHT: 220.3
HYDROCHLORIDE SALTS ARE USED HAVING
EMPIRICAL FORMULA OF C13H21Cl N20
CONTAINS 86% BASE AND HAVING A MOLECULAR
WEIGHT OF 256.8
43. 4% SOLUTION OF PRILOCAINE HAS A PH of 6.0 – 7.0
pKa is 7.9
ABOUT 40% LESS TOXIC THAN LIDOCAINE
UNDERGOES BIOTRANSFORMATION MORE RAPIDY
THAN LIDOCAINE
ORTHOTULUIDINE A METABOLITE PRODUCES
METHEMOGLOBIN IN LARGE DOSES
CONTRAINDICATED IN PATIENTS WITH
CONGENITAL OR IDIOPATHIC
METHEMOGLOBINEMIA
44. • 400mg PRODUCES A METHEMOGLOBIN LEVEL
OF ONLY ABOUT 1% IN THE BLOD
• LEVELS LESS THAN 20% RARELY PRODUCE
SYMPTOMS
• SYMPTOMS INCLUDE: CYANOSIS COUPLED
WITH RESPIRATORY OR CIRCULATORY DISTRESS
• SYMPTOMS MAY BE REVERSED WITH IV
ADMINISTRATION OF 1-2mg/Kg OF 1%
METHYLENE BLUE
45. AVAILABLE IN 4% SOLUTION WHICH WITHOUT
EPINEPHRINE GIVES 60 MINUTES OF WORKING
ANESTHESIA
WHEN EPINEPHRINE IN A 1:200,000
CONCENTRATION IS ADDED TO 4% CITANEST THE
PRODUCT IS CALLED CITANEST FORTE
DURATION OF PULPAL ANALGESIA IS ABOUT 60-90
MINUTES
46. BUPIVACAINE
CRYSTALLINE POWDER FREELY SOLUBLE IN 95% ETHANAL
AND WATER AND SLIGHTLY SOLUBLE IN CHLOROFORM OR
ACETONE
PH 4.5-6.5 AND pKa IS 8.1
AMIDE DERIVATIVE STRUCTURALLY SIMILAR TO
MEPIVACAINE WITH A BUTYL GROUP REPLACING THE
METHYL GROUP IN THE HYDROPHYLIC END
MARCAINE: BUPIVACAINE, 0.5% WITH 1:200,000
EPINEPHRINE AVAILABLE IN CONVENTIONAL 1.8 ml
CARTRIDGE
ALSO SUPPLIED IN 10, 2O AND 50 ml VIALS CONTAINING
0.25%, 0.5% OR 0.75% SOLUTION WITHOUT A
VASOCONSTRICTOR OR WITH 1:200,000 EPINEPHRINE
47. • STRUCTURAL MODIFICATION HAS RESULTED IN THE
PRODUCTION OF AN AGENT THAT HAS 35 FOLD INCREASE
IN OIL WATER PARTITION COEFFICIENT PLUS A SIGNIFICANT
INCREASE IN PROTEIN BINDING QUALITIES
• THE NET EFFECT IS A 4 FOLD INCREASE IN INTRINSIC
ANESTHETIC ACTIVITY AND DURATION OF ACTION
• IT IS 4 TIMES AS POTENT AND TOXIC AS MEPIVACAINE AND
LIDOCAINE
• PULPAL ANESTHESIA IS INCREASED TO 3 HOURS
• DURATION OF SOFT TISSUE ANESTHESIA MAY EXTEND TO 12
HOURS
48. • A PERIOD OF ANELGESIA PERSISTS AFTER THE RETURN OF
OTHER SENSATIONS, HENCE THE NEED OF ANALGESIC DRUG
IS REDUCED OR ELIMINATED
• SHOULD NOT BE ADMINISTERED TO CHILDREN
UNDERGOES BIOTRANSFORMATION IN LIVER BY
CONJUGATION WITH GLUCURONIC ACID.
TOTAL DOSE IN HEALTHY ADULT SHOULD NOT EXCEED
2mg/Kg (0.9mg/lb)NOT TO EXCEED 225 mg WITH 1:200,000
EPINEPHRINE OR 175 mg WITHOUT A VASOCONSTRICTOR
TOTAL DOSE MAY BE REPEATED UPTO ONCE EVERY 3 HOURS
NOT TO EXCEED 400 mg IN 24 HOURS
49. ETIDOCAINE
WHITE CRYSTALLINE POWDER FREELY SOLUBLE IN
95% ETHANAL AND WATER
PH IS 3-5 AND pKa IS 7.7
AMIDE DERIVATIVE, STRUCTURALLY SIMILAR TO
LIDOCAINE, WITH A PROPYL FOR AN ETHYL GROUP
AT THE AMINE END AND THE ADDITION OF AN ETHYL
GROUP AT THE ALPHA CARBON IN THE
INTERMEDIATE CHAIN
PRESENTLY NOT AVAILABLE IN A DENTAL CARTRIDGE
IT SUPPLIED IN 30 AND 50 ml VIALS CONTAINING
0.5% OR 1% SOLUTION OF ETIDOCAINE WITHOUT A
VASOCONSTRICTOR OR WITH 1:200,000 EPINEPHRINE
50. • A 20ml VIAL CONTAINING 1.5% ETIDOCAINE WITH
1:200,000 EPINEPHRINE IS ALSO AVAILABLE
• 50 FOLD INCREASE IN OIL WATER PARTITION COEFFICIENT
AND ALMOST 2 TIMES PROTEIN BINDING CHARACTERISTICS
• FASTER ONSET AND LONGER DURATION
• 4 TIMES INCREASE IN ANESTHETIC ACTIVITY AND 2 TIMES
LONGER DURATION OF ACTION THAN LIDOCAINE
• NOT ADMINISTERED TO CHILDREN
51. TWICE AS TOXIC AS LIDOCAINE
TOTAL DOSE SHOULD NOT EXCEED 4mg/Kg (1.8mg/lb) TO A
MAXIMUM OF 300 mg WHEN USED WITHOUT A
VASOCONSTRICTOR
4.4mg/Kg (2mg/lb) TO A MAXIMUM OF 400mg WHEN
COMBINED WITH 1:200,000 EPINEPHRINE
INCREMENTAL DOSE MAY BE REPEATED EVERY 2 TO 3
HOURS
52. TOPICAL ANESTHETICS
DIRECT APPLICATION TO ABRADED SKIN OR
TO THE MUCOUS MEMBRANE SURFACE
PORELY SOLUBLE IN WATER AND DO NOT
FORM SOLUBLE ACID SALTS
MOST COMMON EXCEPTIONS ARE
LIDOCAINE AND TETRACAINE
LIDOCAINE 5% OR 10%
TETRACAINE 1% OR 2%
HIGHER CONCENTRATIONS ARE REQUIRED
FOR DIFFUSION THROUGH MUCOUS
MEMBRAN
53. • IN ADDITION THE MOST COMMONLY USED TOPICAL
ANESTHETICS ARE BENZOCAINE (ETHYL AMINOBENZOATE)
AND BENZYL ALCOHOL
• WATER INSOLUBLE TOPICAL ANESTHETICS
• SOLUBLE IN VEHICALS SUCH AS ALCOHOL, POLYETHYLENE
GLYCOL, PROPYLENE GLYCOL OR
CARBOXYMETHYLCELLULOSE THAT MAKES THEM
AMENABLE TO SURFACE APPLICATION
• POORLY ABSORBED AND SYSTEMIC TOXICITY VIRTUALLY
UNKNOWN
54. BENZOCAINE
CLOSELY RELATED TO PROCAINE
ESTER OF AMINOBENZOIC ACID
NO BASIC NITROGEN GROUP, HENCE UNABLE
TO FORM SOLUBLE ANESTHETIC SALTS
HURRICAINE CONTAINS BENZOCAINE
IRRITATING IF INJECTED IN TO TISSUE
CAN PRODUCE TOXIC SYMPTOMS IF
ABSORBED IN SUFFICIENT QUANTITIES
55. LIDOCAINE
AVAILABLE IN TWO FORMS: LIDOCAINE BASE
LIDOCAINE
HYDROCHLORIDE
LIDOCAINE BASE
INSOLUBLE IN WATER
5% CONCENTRATION
EXCELLENT SURFACE ANESTHESIA WITHIN 15 SECONDS OF
APPLICATION
SINGLE APPLICATION HAS A DURATION OF ABOUT 30
MINUTES
POORLY ABSORBED, SYSTEMIC TOXICITY IS NEGLIGIBLE
10% LIDOCAINE BASE IN AN AEROSOL SPRAY WITH A
METERED DOSE VALVE DISCHARGES 10mg PER SPRAY ALSO
56. WATER SOLUBLE TOPICAL ANESTHETICS
PRIMARY DISADVANTAGE: RAPID ABSORPTION IN TO
BLOOD STREAM
BENZYL ALCOHOL
AROMATIC ALCOHOL SOLUBLE IN WATER
VERY IRRITATING ON INJECTING INTO THE TISSUES
4% TO 10% SOLUTIONS
SHORT ACTING
LESS TOXIC THAN ETHYL AMINOBENZOATE
57. TETRACAINE HYDROCHLORIDE
VERY POTENT
HIGHLY WATER SOLUBLE
ONSET OF ACTION IS SLOW BUT DURATION IS RELATIVELY
LONG LASTING (45 MINUTES TO 1 HOUR)
FREQUENTLY COMBINED WITH BENZOCAINE, AN AGENT
OF RAPID ONSET AND BRIEF DURATION
A MIXTURE OF BENZOCAINE 14%, BUTAMBEN 2% AND
TETRACAINE 2% DISSOLVED IN DIPROPYLENE GLYCOL
UNDER THE NAME CETACAINE IS EXTENSIVELY USED
MAXIMUM DOSE: 20 mg OR 1 ml OF 2% SOLUTION
58. LIDOCAINE HYDROCHLORIDE
2% OR 4% CONCENTRATION
MAXIMUM RECOMMENDED DOSE IS 200mg
WHEN APPLIED BY MEANS OF COTTON APPLICATORS THE
SUGGESTED MAXIMUM DOSE IS 1 TO 5 ML (40 TO 200MG)
OR 0.6 TO 3 mg/Kg (0.3 TO 1.5 mg/lb) NOT TO EXCEED
300mg OR 4.5mg/kg
60. THE VASOCONSTICORS COMMONLY USED IN DENTAL
LOCAL ANESTHETIC SOLUTIONS CAN BE DIVIDED INTO THE
FOLLOWING 3 GROUPS
1. PYROCATECHINE DERIVATIVES- EPINEPHRINE AND
NOREPINEPHRINE
2. BENZOL DERIVATIVE- LEVONORDEFRIN
3. PHENOL DERIVATIVE- PHENYLEPHRINE
61. MODE OF ACTION
SYMPATHOMIMETICS AMINES ACT BY
1. ATTACHING TO AND DIRECTLY STIMULATING ADRENERGIC
RECEPTORS
2. ACTING INDIRECTLY BY PROVOKING THE RELEASE OF
ENDOGENOUS CATECHOLAMINES
3. A COMBINATION OF DIRECT AND INDIRECT ACTION
ALL VASOCONSTRICTORS USED IN CONJUNCTION WITH
LOCAL ANESTHETICS ARE DIRECTLY ACTING AGENTS
62. EPINEPHRINE
LEVOROTATORY ALKALOID SECRETED BY ADRENAL
MEDULLA
HIGHLY SOLUBLE IN WATER
MOST POTENT VASOCONSTRICTOR USED
USED AS STANDARD OF COMPARISON
HAS A PRESSOR POTENCY OF ONE
CONCENTRATIONS FROM 1:50,000 TO 1:250,000 ARE USED
63. CVS:
BETA1 STIMULATION RESULTS IN AN INCREASE IN HEART RATE
(POSITIVE CHRONOTROPIC EFFECT)
INCREASE IN STROKE VOLUME, CARDIAC OUTPUT AND
OXYGEN CONSUMPTION
INCREASED IRRITABILITY OF MYOCARDIUM- PREMATURE
VENTRICULAR CONTRACTIONS AND TACHYCARDIAS
OTHER EFFECTS: INCREASED BLOOD GLUCOSE LEVELS,
INCREASED GLYCOGENOLYSIS AND PUPILLARY DILATION
64. NOREPINEPHRINE
MAJOR PRESSOR AMINE FOUND IN THE
POSTGANGLIONIC ADRENERGIC NERVE
WHITE CRYSTALLINE SALT, FREELY SOLUBLE IN WATER
WITH A PH OF 3.4
IT HAS NO RADICAL ON THE AMINO GROUP
ACTS PREDOMINANTLY ON THE ALPHA RECEPTOR SITE
DOSE SHOULD NOT EXCEED 0.34mg OR 10ml OF
SOLUTION CONTAINING 1:30,000
65. LEVONORDEFRIN
IT IS ONE FIFTH AS ACTIVE AS EPINEPHINE
LOWER SYSTEMIC TOXICITY
IT ACTS DIRECTLY AND ALMOST EXCLUSIVELY ON THE
ALPHA RECPTOR SITES
DOSE: WHEN 1:10,000 CONCENTRATION IS USED IT
SHOULD BE LIMITED TO A TOTAL DOSE OF 1mg
PATIENTS WITH CARDIAC CONDITIONS ITS USE SHOULD
BE LIMITED TO A MAXIMUM OF 0.4mg
66. PHENYLEPHRINE
SIMILAR TO EPINEPHRINE BUT DIFFERING STRUCTURALLY .
IT HAS ONLY ONE HYDROXYL GROUP ON THE BENZENE
RING
IT IS THE MOST STABLE AND WEAKEST OF ALL
VASOCONSTRICTORS AND LONG LASTING
USED IN CONCENTRATIONS 10 TO 20 TIMES THOSE OF
EPINEPHRINE: 1:2,500
IT IS A PURE ALPHA RECEPTOR AGONIST
DOSE: 1:2,500 LIMITED TO 4mg AT ONE TIME
IN PATIENTS WITH CARDIAC CONDITIONS : REDUCED TO 1.6
mg
67. TERMINATION OF ACTION AND
POTENTIAL DRUG INTERACTION
TRICYCLIC ANTIDEPRESSANTS INTERFERE WITH THE
REUPTAKE MECHANISM
DEACTIVATION BY EXTRANEURONAL ENZYME (CATECHOL-
O-METHYL TRANSFERASE)
UPTAKE BY BLOOD SYSTEM
INTRANEURONAL ENZYME DESTRUCTION (MONOAMINO
OXIDASE)
MAO I INHIBITOR
ALPHA ADRENERGIC BLOCKERS: PHENOTHIAZINE
EPINEPHRINE REVERSAL EFFECT
BETA ADRENERGIC BLOCKERS (PROPRANOLOL, INDERAL)
68. SELECTION OF VASOCONSTRICTORS
1. DURATION OF DESIRED EFFECT
2. PHYSICAL CONDITION OF THE PATIENT
3. DESIRE TO PRODUCE HEMOSTASIS
4. CONCURRENT MEDICATION
69. Properties of ideal LA
Reversible action.
Non-irritant.
No allergic reaction.
No systemic toxicity.
Rapid onset of action.
Sufficient duration of action.
Potent.
Stable in solutions.
Not interfere with healing of tissue.
Have a vasoconstrictor action or compatible with VC.
Not expensive
73. Mechanism of action
- Inhibiting excitation of nerve endings or blocking
conduction in peripheral nerves. Binding to and inactivating
sodium channels.
- Local Anaesthetics are alkaloid bases that are combined with
acids, usually hydrochloric, to form water soluble salts. All
anaesthetic salts are formed by a combination of weak base
and a strong acid. The salts are used because they are
stable and soluble in water; water solubility isnecessary for
their diffusion through interstitial fluids to the nerve fibers.
74. - Sodium influx through these channels is necessary for the
depolarization of nerve cell membranes and subsequent propagation
of impulses along the course of the nerve.
- when a nerve loses depolarization and capacity to propagate an
impulse, the individual loses sensation in the area supplied by the
nerve
75. - block nerve fiber conduction by acting on nerve membranes
- inhibit sodium ion activity
- blocks depolarization--> blocks nerve conduction
76. When the influx of sodium is interrupted, an action potential cannot
arise and signal conduction is inhibited. LA drugs bind more readily
to sodium channels in activated state, thus onset of neuronal
blockade is faster in neurons that are rapidly firing. This is referred
to as state dependent blockade.