Exam 3: Pharmacology of Local Anesthetic Agents

The most potent local anesthetic is bupivacaine which has the greatest degree of lipid solubility.

If more anesthetic is needed for a procedure,it is important to reinject the anesthetic after the mantel fibers have fully recovered.

Dissociation constant refers to which of the following descriptions?

Local anesthetics affect the CNS and CVS after biotransformation.

Prilocaine is biotransformed in the liver only.

Answer the following questions based upon the following case study. Sam, a businessman who travels extensively, has been in your dental chair for 2 hours for extensive nonsurgical perio procedures. He insisted on having a long appointment in order "to get everything done at one time." A review of Sam's health history reveals that he is taking medications for high blood pressure; has no known allergies; recently quit smoking; and is a recovering alcoholic. He mentions that he is going through a divorce and that he is leaving for China within the week. You explain to Sam that, because of the long appointment and the amount of work that you need to accomplish, you will use a long-lasting local anesthetic to ensure his comfort. You apply topical benzocaine to all injection sites on the right side. You choose to administer the local anesthetic bupivacaine because of its long-lasting effect. Although Sam is a good-natured patient, you experience difficulty in achieving the desired level of anesthesia in order to keep Sam comfortable. Within 5 minutes of the administration of yet another cartridge of anesthetic, Sam begins to complain of a headache and you notice that he is slurring his words. You quickly retake his blood pressure only to discover that it has actually gone down since the beginning of the appointment. What thoughts should be going through your mind at this time? -Based on Sam's physical symptoms,what should you consider?

Esters,benzocaine,tetracaine,and procaine are hydrolyzed in the plasma by the enzyme pseudocholinesterase and by liver esterases.Procaine is metabolized to PABA and is the major metabolic byproduct responsible for allergic reactions.

Which anesthetic drug has a short half-life of 45 minutes and is the least toxic of the anesthetics?

The rate of systemic absorption of local anesthetics depends on the total dose,concentration,route of administration,vascularity of tissues,and presence or absence of a vasoconstrictor.

Answer the following questions based upon the following case study. Sam, a businessman who travels extensively, has been in your dental chair for 2 hours for extensive nonsurgical perio procedures. He insisted on having a long appointment in order "to get everything done at one time." A review of Sam's health history reveals that he is taking medications for high blood pressure; has no known allergies; recently quit smoking; and is a recovering alcoholic. He mentions that he is going through a divorce and that he is leaving for China within the week. You explain to Sam that, because of the long appointment and the amount of work that you need to accomplish, you will use a long-lasting local anesthetic to ensure his comfort. You apply topical benzocaine to all injection sites on the right side. You choose to administer the local anesthetic bupivacaine because of its long-lasting effect. Although Sam is a good-natured patient, you experience difficulty in achieving the desired level of anesthesia in order to keep Sam comfortable. Within 5 minutes of the administration of yet another cartridge of anesthetic, Sam begins to complain of a headache and you notice that he is slurring his words. You quickly retake his blood pressure only to discover that it has actually gone down since the beginning of the appointment. What thoughts should be going through your mind at this time? -Reflecting on your experience with Sam,what other factors may contribute to an incident similar to Sam's?

The speed of recovery from local anesthetic is determined by the degree of binding to the receptor site of each anesthetic.

Which part of the chemical structure of a local anesthetic determines the pattern of biotransformation of the anesthetic?

Which component of the local anesthetic molecule improves the lipid solubility,which facilitates the penetration of the anesthetic through the lipid-rich membrane where the receptor sites are located?