Local Anaesthesia

Vocabulary flashcards about local anesthesia.

Topical Anaesthetic

Used to numb the surface of the gums or mucous membranes before injections or minor procedures.

Common Forms of Topical Anaesthetic

Gels, creams, sprays, liquids, pre-soaked pellets.

Active Ingredients in Topical Anaesthetics

Typically contain lidocaine, benzocaine, or tetracaine.

Duration of action of Topical Anaesthetics

Provides short-term numbing (usually 15-30 minutes).

Indications for Topical Anaesthetics

Used for procedures like scaling, root debridement, or before administering local anaesthetic injections.

Bevel

Present to ensure easy, painless puncture of soft tissue.

Self Aspirating Syringes

Spring mechanism that aids automatic aspiration.

Local Anaesthesia Definition

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

Action Potentials

A rapid, brief reversal in electrical charge across the Axon’s membrane

Pharmacokinetics

The movement of drugs inside the body.

Factors influencing absorption rate

Chemical nature of the drug, site of injection, local blood flow, Vasoconstriction.

Excretion

Principal site of excretion of drugs is the kidneys.

Examples of Amides

Lignocaine/Lidocaine, Prilocaine, Articaine, Bupivacaine, Mepivacaine.

Examples of Esters

Procaine/Novocaine, Tetracaine

Local anesthetics in dentistry

create a reversible blockage of pain/sensation signals in peripheral nerves, are natural vasodilators and so contain vasoconstrictors to reduce localised bleeding.

General Indications for Topical Anaesthetics

To anaesthetise mucous membranes or provide surface anaesthesia of gingiva prior to injections.

Vasoconstrictors

Increase duration of action of L.A.

Basic composition of Local Anesthetics

Increase duration of action, convert agent so it is water soluble, prevents oxidation of stablilizer/preservatives, increases volume of solution.

Vasoconstrictors used in dentistry

Adrenaline, Felypressin

Prilocaine- Pharmacological properties

Slighter slower onset than lignocaine. Less vasodilatory, distributed more rapidly, larger volume of distribution.

Articaine: Onset of action

2 minutes.

Articaine Metabolism

Articaine undergoes some biotransformation in the blood plasma in addition to the liver.

Safest local anaesthetic drug for use in patients with hepatic and renal impairments.

Articaine.

Mepivacaine Pharmacological properties

Least vasodilatory of all amides; extremely low incidence of allergy.

Bupivacaine Pharmacological properties

Long lasting and high protein binding (increases duration of action).

Contraindication

Use of this type of L.A for a client with these conditions is inadvisable

Conditions that contraindicate local anesthesia

Hypersensitivity to any components, Serious IV conduction defects, Severe hypotension, Severe liver and renal disease.

Methaemoglobinaemia

Where metabolites of the LA Prilocaine induce formation of methaemoglobin inducing cyanosis like state.

Local anesthetics in dentistry

create a reversible blockage of pain/sensation signals in peripheral nerves.

When LA is contraindicated

hypersensitivity to any components, serious IV conduction defects, severe hypotension, or severe liver and renal disease

Indications of LA

include pain management, surgical procedures, and dental work where localized sensation loss is required to facilitate patient comfort and minimize systemic effects.

What do you need to check on the cartrudge

signs of damage, expiration date, proper labeling (batch number, vasoconstrictor), volume, contents

What are the properties of LA

speed on onset, potency, duration of action, low tissue pH

Lignocaine duration of action

60-120 mins soft tissues

Prilocaine

duration of action 150-210 mins soft tissues

Articaine

duration of action 180-360 mins soft tissues

When is articaine contraindicated

Articaine is contraindicated in patients with a known allergy to the drug or local anesthetics in its class, as well as in cases of severe liver dysfunction or certain cardiac conditions.

Mepivacaine

duration of action 120-180 mins soft tissues

Bupivacaine

duration of action 240-540 mins soft tissues

not used by OHTs

When is adrenaline contraindicated

Adrenaline is contraindicated in patients with severe hypertension, cardiovascular disease, uncontrolled diabetes and hyperthyroidism, adrenal tumours