Local Anesthetics Overview

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Questions and Answers

What is the primary action of vasoconstrictors during surgery?

Increase blood flow to tissues

Enhance the absorption of local anesthetics

Decrease the risk of toxicity (correct)

Increase bleeding during procedures

Among the following, which is classified as a catecholamine?

Methoxamine

Dopamine (correct)

Ephedrine

Phenylephrine

Which adrenergic receptor is primarily responsible for vasoconstriction?

Beta (β) receptors

Delta (δ) receptors

Alpha (α) receptors (correct)

Gamma (γ) receptors

What is one of the systemic effects of epinephrine?

Hypertension Signup and view all the answers

In which clinical situation is epinephrine NOT commonly used?

Chronic pain management Signup and view all the answers

What does the ASA classification system assess?

Preoperative physical status of patients Signup and view all the answers

Which of the following is an indirect-acting adrenergic agent?

Amphetamine Signup and view all the answers

What is the primary characteristic of articaine that distinguishes it from other amide-type local anesthetics?

It contains a thiophene ring. Signup and view all the answers

What is the typical onset of action for articaine when used in a block procedure?

2 to 3 minutes Signup and view all the answers

What is the primary metabolic effect of epinephrine?

Increased glycogenolysis leading to increased blood sugar Signup and view all the answers

Which local anesthetic is recommended for patients with an allergy to sulfite-containing drugs?

Mepivacaine 3% plain Signup and view all the answers

What is the maximum recommended dose of articaine for an adult patient?

7.0 mg/kg body weight Signup and view all the answers

What is the classification of articaine?

Amide with both amide and ester characteristics Signup and view all the answers

What potential side effect is associated with articaine?

Methemoglobinemia Signup and view all the answers

Which property of articaine makes it similar to lidocaine?

Similar vasodilating effect Signup and view all the answers

For what reason is articaine's metabolism considered unique among amide-type local anesthetics?

It undergoes hydrolysis in both plasma and liver. Signup and view all the answers

Which patient group is considered at higher risk for adverse reactions when using local anesthetics?

Patients with significant cardiovascular disease Signup and view all the answers

How many mg of mepivacaine does a 2% solution contain per milliliter?

20 mg/ml Signup and view all the answers

What is the maximum amount of 3% Mepivacaine cartridges that can be used based on an individual's weight?

54 mg per cartridge Signup and view all the answers

Which of the following local anesthetics has the highest amount of mepivacaine per cartridge?

4% Articaine with Epi Signup and view all the answers

What is the correct formula to calculate the maximum number of carpules of 2% Mepivacaine per visit?

Body weight X 6.6 mg/kg Signup and view all the answers

What is the maximum recommended dosage of epinephrine for a normal healthy patient (ASA I)?

0.2 mg Signup and view all the answers

How does levonordefrin primarily exert its effects?

Through direct alpha-receptor stimulation Signup and view all the answers

What is a common side effect of levonordefrin when used at higher doses?

Ventricular tachycardia Signup and view all the answers

What is the maximum dosage of levonordefrin recommended for all patients during a dental appointment?

1 mg Signup and view all the answers

Which factor does NOT influence the selection of vasoconstrictors?

Patient's allergy history Signup and view all the answers

What is one of the benefits of using a vasoconstrictor in dental procedures?

Prolonged duration of action of the anesthetic Signup and view all the answers

Which condition is specifically associated with the maximum dosage of epinephrine for patients with clinically significant cardiovascular disease?

0.04 mg Signup and view all the answers

What potential effect does levonordefrin have compared to epinephrine?

Less cardiac stimulation Signup and view all the answers

What is the primary classification of bupivacaine?

Amide Signup and view all the answers

Which condition is a contraindication for the use of bupivacaine?

Heart disease Signup and view all the answers

What is the mix of local anesthetics in EMLA cream?

2.5% Lidocaine and 2.5% Prilocaine Signup and view all the answers

What is the typical duration of action for topical anesthetics?

2-3 mm depth of tissue Signup and view all the answers

What type of local anesthetic is benzocaine?

Ester Signup and view all the answers

For which patients is Dyclonine Hydrochloride particularly useful?

Those allergic to ester anesthetics Signup and view all the answers

Which of the following is NOT a factor to consider when selecting a local anesthetic for a patient?

Patient's age Signup and view all the answers

Which of the following is true regarding mucous membranes in relation to topical anesthetics?

They allow anesthetics to penetrate better than intact skin. Signup and view all the answers

Study Notes

Articaine

Articaine is classified as an amide, but it possesses both amide and ester characteristics
It is 1.5 times more potent than lidocaine
Toxicity is comparable to lidocaine and procaine
It is the only amide-type local anesthetic that contains a thiophene group, which enhances its lipid solubility and penetration into tissues
Metabolises in plasma (hydrolysis by plasma esterase) and liver (hepatic microsomal enzymes)
Excretion via kidneys, approximately 5% to 10% unchanged
Vasodilating effects similar to lidocaine

Bupivacaine

Classified as an Amide
Long-acting local anesthetic
Potency is 4 times greater than lidocaine
Indicated for lengthy dental procedures (oral surgery, implant surgery, periodontal procedures)
Used to manage postoperative pain

Topical Anesthetics

Intact skin prevents local anesthetic diffusion
Mucous membranes and injured skin allow topical anesthetics to reach nerve endings
Topical anesthesia is effective only on surface tissues (2 to 3 mm deep)
More concentrated forms of the drug are used topically (5% or 10% lidocaine) than for injection (2% Lidocaine)
Common topical anesthetics include: benzocaine, dyclonine hydrochloride, EMLA, lidocaine
Benzocaine 20% is poorly soluble in water, remains at the site of application longer, providing a prolonged duration of action, not suitable for injection
Dyclonine Hydrochloride is classified as a ketone derivative and can be used in patients allergic to common anesthetics

EMLA

EMLA cream contains 2.5% Lidocaine + 2.5% Prilocaine
Emulsion where oil phase is a eutectic mixture of lidocaine and prilocaine
Works on intact skin
Applied 1 hour prior to procedure

Vasoconstrictors

Vasoconstrictors decrease blood flow and the rate of local anesthetic absorption into the cardiovascular system, lowering anesthetic blood levels
Reduce risk of toxicity, increase duration of action, and promote hemostasis (decrease bleeding)
Alpha (α) receptors cause vasoconstriction, beta (β) receptors promote vasodilation and bronchodilation
Epinephrine directly activates both alpha (α) and Beta (β) adrenergic receptors
Levonordefrin primarily activates alpha receptors

Epinephrine

Increases heart rate and cardiac output
Increases systolic blood pressure
Causes vasoconstriction of smaller arterioles
Acts as a bronchodilator
Increases oxygen consumption and glycogenolysis (increasing blood sugar)

Levonordefrin

Less potent than epinephrine
Less cardiac and CNS stimulation compared to epinephrine

Selecting a Local Anesthetic

Consider the duration of pain control needed
Assess the potential for post-treatment pain
Consider the risk of self-harm
Evaluate the need for hemostasis
Review contraindications (medical history, allergies, pregnancy)

Selecting a Vasoconstrictor

Consider the length of the dental procedure
Assess the need for hemostasis during and after the procedure
Evaluate the requirement for post-operative pain control
Review the medical status of the patient
Benefits and risks of vasoconstrictors must be weighed against benefits and risks of using a plain anesthetic solution

Contraindications for Vasoconstrictors

Individuals with significant cardiovascular disease (ASA classes 3 and 4)
Patients with certain non-cardiovascular diseases (thyroid dysfunction, diabetes, sulfite sensitivity)
Patients receiving MAO inhibitors (monoamine oxidase inhibitors)

Calculating Cartridge Maximums

2% Mepivacaine with Epi 1:100,000 (red color): Maximum carpules/visit = (Body weight X 6.6mg/kg) / 36 mg/cartridge (36 mg/cartridge calculated from 20 mg mepivacaine/ml X 1.8 ml/cartridge)
3% Mepivacaine without Epi (green color): Maximum carpules/visit = (Body weight X 6.6mg/kg) / 54 mg/cartridge (54mg/cartridge calculated from 30 mg mepivacaine/ml X 1.8 ml/cartridge)
4% Articaine with Epi (blue color): Maximum carpules/visit = (Body weight X 7 mg/kg) / 72 mg/cartridge

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Description

This quiz covers various local anesthetics including Articaine, Bupivacaine, and topical anesthetics. Learn about their classifications, potencies, mechanisms of action, and applications in dental procedures. Test your knowledge on their pharmacological properties and clinical uses.