Local Anesthetic Calculations-Review & Practice

 

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Anesthetic percent and mg/ml maximum dosages by drug Vasoconstrictors per carpule Vasoconstrictor dosages

Watch the videos:

Basic Dosage Calculations

Factoring in the Absolute Maximum Dose

Maximum dose when using 2 different anesthetics

Vasoconstrictor Calculations

Practice Problems

Test your knowledge:

How much lidocaine 2% can a 140 lb. patient receive in a single appointment? Do not factor in vasoconstrictors. Answer in both mg. and carpules.

140 lbs x 2.0 mg/lb for lido = 280 mg. 36 mg of lido in a carp. divided into 280 = 7.7

How many milligrams of lidocaine 2% can a 160 lb. patient receive in a single appointment?

160 lbs x 2.0 mg/lb for lido = 320 mg, however the absolute maximum per appointment is 300 mg.

How many carpules of lidocaine 2% with 1:100,000 epi can a patient with ischemic heart disease receive in a single appointment?

A cardiac patient can have .04 mg. of epi per appointment. There are .018 mg of epi in a carpule with 1:100,000 concentration. .04 divided by .018 = 2.2 carpules

How many carpules of articaine 4% can a 110 lb. patient receive in a single appointment, not including vasoconstrictors?

110 lb. x 3.2 mg/lb for articaine = 352 mg. 4% anesthetic has 72 mg per carpule. 352 divided by 72 = 4.8 carps (always round down)

How many carpules of Lido 2% 1:100,000 anesthetic can a 170 lb. cardiac patient receive? Round your answer to the nearest carpule.

A cardiac patient can have .04 mg of epi per appointment. There are .018 mg in a 1:100,000 concentration carpule. .04 divided by .018 = 2.2 carps. We round down to 2. The weight does not matter here as the amount of epi the patient can have is far less than the amount of lidocaine.

How many mg. of mepivicaine 3% plain can a 200 lb. person receive in a single visit?

200 lbs x 2.0 mg/lb = 400 mg, however the absolute maximum for mepivacaine is 300 mg per appointment.

We have given a healthy 135 lb person 2 carps of mepivacaine 3% plain. How much articaine, in mg. can we add?

135 lbs x 2.0 mg/lb = 270 mg is max of mepivicaine. 135 lbs x 3.2 mg/lb = 432 is max of articaine. We use the lower number of 270. Mepivicaine 3% has 54 mg of drug in it and we have given 2 = 108 mg. Subtract what we have given from 270 mg and we get 162 mg.

How many carpules of anesthetic with 1:20,000 levonordefrin can a healthy 160 lb. patient receive?

A healthy patient can have 1.0 mg of levonordefrin. There is .09 mg/carp for a 1:20,000 concentration. 1.0 mg divided by .09 = 11 carps.

We have given a patient 2 carpules of lidocaine 2% plain. How much mepivicaine 3% plain can we add if the patient is 140 lbs?

140 lbs x 2.0 mg/lb = 280 mg for lido, mepivicaine is also 2.0 mg/lb so will also be 280 mg. We have given 36 mg. x 2 carps= 72. 280-72=208 mg. There are 54 mg in 3% mepivicaine. 208 divided by 54 = 3.8 carps that we can give the patient yet.

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