## Local Anesthesia For Dental Professionals 2nd Edition By Bassett, DiMarco _ Naughton – Test Bank

Chapter 7

Dose Calculations for Local Anesthetic Solutions

Match the following

A) MRD 90 mg

B) MRD 0.04 mg

C) 3.2 mg/lb

D) 3.6 mg/lb

E) MRD 500 mg

F) 54 mg/cartridge

G) Based on child’s weight

H) 1.8 ml

I) MRD 1.0 mg

J) Based on child’s age

1) Articaine

Objective: 1, 3, 5

2) Bupivacaine

Objective: 1, 3, 5

3) Cardiac dose

Objective: 1, 3, 5

4) Cartridge volume

Objective: 1, 3, 5

5) Clark’s rule

Objective: 1, 3, 5

6) Levonordefrin

Objective: 1, 3, 5

7) Lidocaine

Objective: 1, 3, 5

8) Mepivacaine

Objective: 1, 3, 5

9) Prilocaine

Objective: 1, 3, 5

10) Young’s rule

Objective: 1, 3, 5

Answers: 1) C 2) A 3) B 4) H 5) G 6) I 7) E 8) F 9) D 10) J

True or false

1) The maximum recommended dose for each solution is dependent on the drug that limits the total volumes that may be delivered.

A) True

B) False

Answer: A

Objective: 2

2) In solutions containing both a local anesthetic and a vasoconstrictor drug, the maximum recommended dose of the local anesthetic is usually the limiting drug.

A) True

B) False

Answer: B

Objective: 3

3) The maximum safe dose of 1:50,000 epinephrine per appointment for a healthy adult is 0.2 mg or 5.5 cartridges.

A) True

B) False

Answer: A

Objective: 3

4) At a concentration of 4%, the amount of drug in a 1.8 ml cartridge is 7.2 mg.

A) True

B) False

Answer: B

Explanation: B) At a concentration of 4%, the amount of drug in a 1.8 ml cartridge is 72 mg 4% solution = 40 mg/ml x 1.8 = 72 mg/cartridge

Objective: 4

5) At a concentration of 0.5%, the amount of drug in a 1.8 ml cartridge is 9 mg.

A) True

B) False

Answer: A

Objective: 4

6) To calculate the milligrams of drug delivered, multiply the total number of cartridges by the total milligrams of drug in each cartridge.

A) True

B) False

Answer: A

Objective: 4

7) When two different drugs are injected, the total of the MRDs for both drugs is the maximum number of milligrams of drugs the patient may receive.

A) True

B) False

Answer: B

Explanation: B) When multiple drugs are administered with different MRDs, the lowest MRD (most toxic drug) is applied when calculating total drug doses.

Objective: 5

8) Calculations of maximum safe doses for vasoconstrictors are determined by mg/lb or mg/kg.

A) True

B) False

Answer: B

Explanation: B) Calculations of vasoconstrictor doses are different compared to those used to determine local anesthetic drug doses. The main differences are that vasoconstrictors are expressed as dilution ratios rather than concentration percentages and maximum doses of vasoconstrictors are not weight dependent.

Objective: 5

9) The maximum safe dose of 1:200,000 epinephrine per appointment for a patient with ischemic heart disease is 0.4 mg or 1.1 cartridges.

A) True

B) False

Answer: B

Explanation: B) The maximum safe dose of 1:200,000 epinephrine per appointment for a patient with ischemic heart disease is 0.04 mg or 4 cartridges (about 4.4, rounded down for safety to 4).

Objective: 5

10) Clark’s rule for determining pediatric drug doses is based on a child’s weight divided by 150 to get the approximate fraction of the adult dose.

A) True

B) False

Answer: A

Objective: 5

Fill in the blank

1) The maximum recommended dose per appointment for bupivacaine is ________.

Answer: 90 mg

Objective: 3

2) The maximum recommended dose per appointment for lidocaine is ________.

Answer: 500 mg

Objective: 3

3) The maximum mg/lb of mepivacaine per appointment is ________.

Answer: 3.0

Objective: 3

4) The maximum mg/lb of prilocaine per appointment is ________.

Answer: 3.6

Objective: 3

5) A 10% solution contains one tenth of a milligram per milliliter or ________ mg/ml.

Answer: 100

Objective: 5

6) A 2% solution of lidocaine contains ________ mg/ml.

Answer: 20

Objective: 5

7) A 2% solution of lidocaine contains ________ mg/cartridge.

Answer: 36

Objective: 5

8) A 3% solution of mepivacaine contains ________ mg/ml.

Answer: 30

Objective: 5

9) A 3% solution of mepivacaine contains ________ mg/cartridge.

Answer: 54

Objective: 5

10) Ralph weighs 175 lb. He has received 72 mg of 2% lidocaine. Ralph can receive a maximum of ________ mg additional lidocaine.

Answer: 428

Objective: 5

11) Susan is a healthy patient and weighs 130 lb. She has received 54 mg of 3% mepivacaine. She could receive a maximum of _________ mg of 4% prilocaine, 1:200,000 epinephrine.

Answer: 336

Objective: 5

Multiple choice

1) The MRD for bupivacaine is:

A) 200 mg

B) 90 mg

C) 300 mg

D) 500 mg

Answer: B

Objective: 3

2) Which of the following information for MRD is not correct?

A) Bupivacaine = 90 mg

B) Lidocaine = 500 mg

C) Mepivacaine = 300 mg

D) Prilocaine = 600 mg

Answer: C

Objective: 3

3) What is the MRD of vasoconstrictor for 2% lidocaine, 1:100,000 epinephrine for a healthy patient?

A) 0.02 mg

B) 2.0 mg

C) 1.0 mg

D) 0.2 mg

Answer: D

Objective: 3

4) What is the MRD in cartridges for 4% prilocaine, 1:200,000 epinephrine for a healthy 150 pound patient?

A) 5

B) 6

C) 8

D) 11

Answer: C

Objective: 3

5) How many milligrams of epinephrine 1:50,000 are available in one cartridge?

A) 0.018 mg

B) 0.050 mg

C) 0.036 mg

D) 0.2 mg

Answer: C

Objective: 3

6) How many milligrams of epinephrine 1:200,000 are available in two cartridges?

A) 0.018

B) 0.18

C) 0.036

D) 0.016

Answer: A

Objective: 3

7) Which of the following pieces of information is not usually required in order to calculate safe doses for local anesthetics and vasoconstrictors?

A) Patient factors such as height, weight, and age

B) Standard cartridge volume and dilution percentages

C) Maximum recommended dose and patient weight

D) Concentration of drug and dilution percentages

Answer: A

Objective: 4

8) A 150-pound patient has received two cartridges of 2% lidocaine, 1:100,000 epinephrine. How many additional cartridges with the same drugs can be administered before reaching the MRD?

A) 5

B) 6

C) 9

D) 11

Answer: C

Objective: 5

9) A 120-pound patient has received three cartridges of 4% prilocaine, 1:200:000 epinephrine. How many more milligrams of prilocaine can this patient receive before reaching the MRD?

A) 72 mg

B) 216 mg

C) 432 mg

D) 600 mg

Answer: B

Objective: 5

10) A healthy 160-pound patient has received three cartridges of 2% lidocaine, 1:50,000 epinephrine during an oral surgical procedure. How many more cartridges with the same drug could this patient receive before reaching the MRD?

A) 2

B) 5

C) 8

D) 10

Answer: A

Objective: 5

11) A patient has received four cartridges of 4% articaine, 1:200,000 epinephrine. How many milligrams of vasoconstrictor has the patient received?

A) 0.018

B) 0.036

C) 0.072

D) 0.36

Answer: B

Objective: 5

12) A 180-pound patient has received three cartridges of 2% lidocaine, 1:100,000 epinephrine. How many additional milligrams of 4% articaine, 1:200,000 epinephrine can be administered before reaching the MRD?

A) 72 mg

B) 192 mg

C) 228 mg

D) 392 mg

Answer: D

Objective: 5

13) A 120-pound patient has received 2 cartridges of 2% mepivacaine, 1:20,000 and does not remain adequately numb during the procedure. How many additional cartridges of 2% lidocaine, 1:100,000 epinephrine may the patient receive before reaching the MRD?

A) 6

B) 9

C) 11

D) 13

Answer: B

Objective: 5

14) What is the MRD of levonordefrin for a 210 pound male patient with ischemic heart disease?

A) 0.02 mg

B) 0.2 mg

C) 0.04 mg

D) 0.4 mg

Answer: B

Objective: 5

15) A patient with cardiovascular disease has received one cartridge of 2% lidocaine, 1:100:000 epinephrine. How many milligrams of vasoconstrictor has this patient received? How many additional milligrams of vasoconstrictor can the patient receive before reaching MRD?

A) 0.018 mg received; 0.022 mg additional

B) 0.009 mg received; 0.391 mg additional

C) 0.36 mg received; 0.4 mg additional

D) 0.18 mg received; 0.22 mg additional

Answer: A

Objective: 5

16) A patient with cardiovascular disease has received two cartridges of 4% articaine, 1:200:000 epinephrine. How many milligrams of vasoconstrictor has this patient received? How many additional cartridges of the same drug solution can the patient receive?

A) 0.009 mg received; two additional cartridges

B) 0.018 mg received; two additional cartridges

C) 0.18 mg received; no additional cartridges

D) 0.036 mg received; no additional cartridges

Answer: B

Objective: 5

17) Using Clark’s rule, calculate the milligrams of 2% lidocaine an 8-year old, 60 pound child can receive before reaching MRD.

A) 60 mg

B) 120 mg

C) 200 mg

D) 300 mg

Answer: C

Objective: 5

18) Using Clark’s rule, a 12-year old, 90 pound child has received two cartridges of 2% lidocaine. How many more cartridges of lidocaine can this child receive before reaching MRD?

A) 3

B) 6

C) 7

D) 8

Answer: B

Objective: 5

19) Using Clark’s rule, calculate the maximum number of milligrams of 3% mepivacaine a 5-year old, 40-pound child can receive before reaching the MRD?

A) 40 mg

B) 80 mg

C) 106 mg

D) 117 mg

Answer: C

Objective: 5

20) Using Young’s rule, calculate the mg of 2% lidocaine a 10-year old, 60-pound child can receive before reaching the MRD?

A) 125 mg

B) 136 mg

C) 200 mg

D) 227 mg

Answer: D

Objective: 5

Short answer/essay

1) What is the MRD of 4% prilocaine plain for a healthy 205 pound male patient?

Answer: The MRD for prilocaine plain is 3.6 mg/lb, with a maximum of 600 mg per appointment. Based on 3.6 mg/lb a 205 lb patient the MRD would be 656 mg, however the 600 mg per appointment should not be exceeded.

Objective: 3

2) What factors are needed to calculate the local anesthetic drug dose delivered for a given patient?

Answer: The following factors are needed: number of milligrams of drug delivered, number of cartridges delivered, MRD for the drug delivered, and weight of the patient.

Objective: 4

3) A 140-pound patient received 144 mg of 2% lidocaine plain. How many more milligrams of the same drug can the patient receive without exceeding the MRD? Provide mathematical formulas required to calculate the correct answer.

Answer: The MRD for 2% lidocaine plain is 3.2 mg/lb with a maximum of 500 mg per appointment. This patient can receive a total of 3.2 mg/lb which equals 448 mg maximum per appointment. (3.2 x 140 = 448). Next, subtract mg of drug received from MRD (448 – 144 = 334 mg). The patient can receive an additional 334 mg of 2% lidocaine plain.

Objective: 4

4) A 180-pound patient received 108 mg of 3% mepivicaine. How many cartridges were used? Provide mathematical formulas required to calculate the correct answer.

Answer: A 3% solution ml/cartridge equals 30 mg/ml. Compute the mg of 3% mepivicaine in one cartridge by multiplying 30 ml/cartridge by ml in one cartridge (30 x 1.8 = 54 mg). Next divide 108 mg received by mg/ml in each cartridge of 3% mepivicaine (108 ÷ 54 = 2). A total of two cartridges of 3% mepivicaine were received.

Objective: 4

5) A 120-pound patient received 108 mg of 2% lidocaine. How many mg of 4% articaine can this patient receive? Provide mathematical formulas to calculate the correct answer.

Answer: The MRD for 2% lidocaine is 3.2 mg/lb with a maximum of 500 mg per appointment. The MRD for 4% articaine is 3.2 mg/lb with no determined maximum per appointment. When considering the MRD for more than one drug, the lowest MRD should be used in calculating the second drug’s MRD. In this case the MRD is the same for both drugs therefore, 284 mg is the MRD. (3.2 x 120 = 284). Next subtract mg of 2% lidocaine received from MRD (284 – 108 = 176). The patient can receive 176 mg of 4% articaine.

Objective: 5

6) Complete the missing information in the table below.

Maximum Recommended Dose per Appointment

Based on Local Anesthetic Drug ONLY*

Drug mg/lb mg/kg mg per appt.*

Articaine 3.2 7.0 –

Bupivacaine 0.9** 2.0** ____mg

Lidocaine _____ 7.0 500 mg

Mepivacaine 3.0 6.6 ____mg

Prilocaine _____ 8.0 600 mg

*Note: “per appt.” values represent dosages for healthy individuals, Values must be adjusted for children, elderly, and medically compromised individuals.

** Canadian recommendations. No U.S. recommendations are available

Source: FDA, ADA/PDR, 5th ed., 2009; Malamed, 6th ed. 2013.

Answer: See bold numbers in table below

Maximum Recommended Dose per Appointment

Based on Local Anesthetic Drug ONLY*

Drug mg/lb mg/kg mg per appt.*

Articaine 3.2 7.0 –

Bupivacaine 0.9** 2.0** 90 mg

Lidocaine 3.2 7.0 500 mg

Mepivacaine 3.0 6.6 400 mg

Prilocaine 3.6 8.0 600 mg

*Note: “per appt.” values represent dosages for healthy individuals, Values must be adjusted for children, elderly, and medically compromised individuals.

** Canadian recommendations. No U.S. recommendations are available

Source: FDA, ADA/PDR, 5th ed., 2009; Malamed, 6th ed. 2013

Objective: 3

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