Chapter 4

Question 1

Local anesthetics are considered what?

Answer 1

Vasodilators

Question 2

Dilation of the mood vessels causes what?

Answer 2

an increase in blood flow to the site of injection.

Question 3

The increase in blood flow causes what?

Answer 3

• Increased rate of anesthetic absorption into the bloodstream
• A decrease in the duration of the anesthetic’s action
• Higher plasma levels of local anesthetics, increasing risk of toxicity.
• Increased bleeding In the area.

Question 4

Vasoconstrictor drugs provide beneficial effects that include

Answer 4

• A decrease in the blood flow by constricting the blood vessels at the injection site.
• An increased duration of the anesthetic’s effects
• Reduction in systemic toxicity due to the increased duration of the anesthetic, requiring a lower administered dose.
• Hemostasis at the injection site.

Question 5

What are the two vasoconstrictors the are added to local anesthetics?

Answer 5

• Epinephrine

- Levonordefrin

Question 6

Both Epinephrine and levonordefrin are considered what?

Answer 6

Sympathomimetic (adrenergic) drugs

Question 7

vasoconstrictors participate in what?

Answer 7

“Fight or Flight” response of the sympathetic nervous system.

Question 8

Exogenous epinephrine

Answer 8

Absorbed from the site if injection

Question 9

Endogenous release of epinephrine

Answer 9

Release of epinephrine from within can compound the adverse effects of exogenous administration of epinephrine via the anesthetic injection containing epinephrine.

Question 10

Epinephrine administered intravenously has a half-life of what?

Answer 10

1-3 minutes

Question 11

What patients should not receive vasoconstrictors?

Answer 11

patients with recent myocardial infarction, coronary bypass surgery, or cerebrovascular accident with the past 6 months.
-Patients with uncontrolled hypertension, angina, arrhythmias, diabetes, and hyperthyroidism.

Question 12

Epinephrine, norepinephrine, and levonordefrine activates what?

Answer 12

Adrenergic receptors

Question 13

Adrenergic receptor sites are divided into two groups

Answer 13

• a receptors: excitatory actions

- b receptors: Inhibitory actions

Question 14

Norepinephrine activates

Answer 14

a receptors

Question 15

Epinephrine activates

Answer 15

• a receptors: Vasoconstrictions

- b receptors: Vasodilatation

Question 16

Stimulation of beta2 receptors by adrenergic drug causes what?

Answer 16

Bronchi of the lungs to dilate

Question 17

Stimulation of beta1 receptors by adrenergic drugs cause what?

Answer 17

Increased rate and force of heart contractions

Question 18

1:50,000 of vasoconstrictors means

Answer 18

1 gram of drug contained or dissolved in 50,000mL solution, or 0.005mg/mL

Question 19

Sodium Bisulfite Preservative Advantages

Answer 19

Increases shelf life

Question 20

Sodium Bisulfite Preservative Disadvantages

Answer 20

• Further acidify the pH of the anesthetic solution; range 3.8 to 5
• Allergic reactions to sodium bisulfites

Question 21

Maximum Recommended Dose

Answer 21

• Healthy patient 0.2mg
• Medically compromised patients 0.04 mg
• Use lowest possible dose
• Proper aspiration
• Inject slowly
• Technique

Question 22

Levonordefrin

Answer 22

-Synthetic vasoconstrictor
-Approximately 1/6 as potent as epinephrine
-Manufactured in higher concentrations
-Contains sodium bisulfite
-Compare mode of action
Levonordefrine: 75% a; 25% b activity
Epinephrine: 50% a: 50% b activity
-produces same systemic actions as epinephrine but to a lesser extent.

Question 23

Levonordefrin is ONLY available with

Answer 23

2% mepivacaine in 1:200,000 mg/mL

Question 24

Levonordefrin is terminated by

Answer 24

reuptake by adrenergic nerves and escaped drug is inactivated by enzymes catechol-O-methyltransferase (COMT) but not monoamine oxidase (MAO)

Question 25

Maximum permissible dose of levonordefrin

Answer 25

- Healthy patient: 0.1 mg | - Medically compromised patient: 0.2 mg

Question 26

Side Effects or Vasoconstrictors

Answer 26

The body is efficient at removing vasoconstrictors; adverse effects of vasoconstrictors normally only last 5 to 10 minutes.

Question 27

Overdose of Vasoconstrictors

Answer 27

5 to 10 minutes is too long for the removal of a vasoconstrictor in patients with severe conditions such as unstable angina, recent myocardial infarction (within 6 months), recent coronary bypass surgery (within 6 months), uncontrolled hypertension, uncontrolled hyperthyroidism, uncontrolled diabetes, uncontrolled dysrhythmias, or congestive heart failure.