AGENTS, CONTROLLING THE FUNCTIONS OF THE PERIPHERAL NERVOUS SYSTEM - Local anesthetics Flashcards
Local anesthetics produce
Blocking pain sensation without loss of consciousness
A good local anesthetic agent shouldn’t cause
Fast onset and long duration of action
Most local anesthetic agents consist of
- Lipophylic group (frequently an aromatic ring)
- Intermediate chain (commonly including an ester or amide)
- Amino group
Which one of the following groups is responsible for the duration of the local anesthetic action?
Intermediate chain
Indicate the local anesthetic agent, which has a shorter duration of action
Procaine
Which one of the following groups is responsible for the potency and the toxicity of local anesthetics?
Lipophylic group
Indicate the drug, which has greater potency of the local anesthetic action
Bupivacaine
Ionizable group is responsible for
The ability to diffuse to the site of action
Which one of the following local anesthetics is an ester of benzoic acid?
Cocaine
Indicate the local anesthetic, which is an ester of paraaminobenzoic acid
Procaine
Which of the following local anesthetics is an acetanilide derivative?
Lidocaine
Indicate the local anesthetic, which is a toluidine derivative
Prilocaine
Which of the following local anesthetics is a thiophene derivative?
Ultracaine
Local anesthetics are
Weak bases
For therapeutic application local anesthetics are usually made available as salts for the reasons of
More stability and greater water solubility
Which of the following statements is not correct for local anesthetics?
charged cationic form penetrates biologic membranes more readily than an uncharged form
Which of the following statements is correct for local anesthetics?
- In a tissue they exist either as an uncharged base or as a cation
- Local anesthetics are much less effective in inflamed tissues
- Low ph in inflamed tissues decreases the dissociation of nonionized molecules
Which one of the following statements about the metabolism of local anesthetics is incorrect?
Metabolism of local anesthetics occurs at the site of administration
Which one of the following statements about the metabolism of local anesthetics is correct?
- Metabolism occurs in the plasma or liver but not at the site of administration
- Ester group of anesthetics like procaine, are metabolized systemically by pseudocholinesterase
- Amides such as lidocaine, are metabolized in the liver by microsomal mixed function oxidases
Indicate the anesthetic agent of choice in patient with a liver disease
Procaine
Which of the following local anesthetics is preferable in patient with pseudocholinesterase deficiency?
Ropivacaine
The primary mechanism of action of local anesthetics is
Blockade of voltage-gated sodium channels
A local anesthetics that is water-soluble
Procaine
Indicate the local anesthetic, which is more lipid-soluble
Bupivacaine
The more lipophylic drugs
- Are more potent
- Have longer duration of action
- Bind more extensively to proteins
Which fibers is the first to be blocked?
B and C fibers
The function, which the last to be blocked:
Motor function
Which of the following fibers participates in high-frequency pain transmission?
Type A delta and C fibers
Local anesthetics that is an useful antiarrhythmic agent?
Lidocaine
Indicate the route of local anesthetic administration, which is associated with instillation within epidural or subarachnoid spaces
Spinal anesthesia
The choice of a local anesthetic for specific procedures is usually based on
- The duration of action
- Water solubility
- Capability of rapid penetration through the skin or mucosa with limited tendency to diffuse away from the site of application
What anesthetics has a short-acting drug?
Procaine
Indicate the local anesthetic, which is a long-acting agent
Bupivacaine
The anesthetic effect of the agents of short and intermediate duration of action can not be prolonged by adding
Dopamine
A vasoconstrictor does not
Reduce a local anesthetic uptake by the nerve
A vasoconstrictor does
- Retard the removal of drug from the injection site
- Hence the chance of toxicity
- Decrease the blood level
Vasoconstrictors are less effective in prolonging anesthetic properties of
Bupivacaine
Which of the following local anesthetics is only used for surface or topical anesthesia?
Cocaine
Indicate the local anesthetic, which is mainly used for regional nerve block anesthesia
Bupivacaine
Which local anesthetics is used for infiltrative and regional anesthesia?
- Procaine
- Lidocaine
- Mepivacaine
Indicate the local anesthetic, which is used for spinal anesthesia
Tetracaine
Which local anesthetics is called a universal anesthetic?
Lidocaine
Most serious toxic reaction to local anesthetics is
- Seizures
- Cardiovascular collapse
- Respiratory failure
Correct statements concerning cocaine include
- Cocaine is often used for nose and throat procedures
- Limited use because of abuse potential
- Causes sympathetically mediated tachycardia and vasoconstriction
Which local anesthetics is more cardiotoxic?
Bupivacaine
Most local anesthetics can cause
- Depression of abnormal cardiac pacemaker activity, excitability, conduction
- Depression of the strength of cardiac contraction
- Cardiovascular collapse
Which local anesthetics causes methemoglobinemia?
Prilocaine
Procaine has all of the following propertie
- It has ester linkage
- Its metabolic product can inhibit the action of sulfonamides
- It is relatively short-acting
Procaine has all of the following properties EXCEPT
It readily penetrates the skin and mucosa
Correct statements concerning lidocaine include
- It is an universal anesthetic
- It widely used as an antiarrhythmic agent
- It is metabolized in liver
Correct statements concerning lidocaine include all of the following EXCEPT
It has esteratic linkage
Which local anesthetics is more likely to cause allergic reactions?
Procaine
Tetracaine has all of the following properties
- Slow onset
- Long duration
- High toxicity
Tetracaine has all of the following properties EXCEPT
Low potency
Correct statements concerning bupivacaine include
- It has amide linkage
- It is a long-acting drug
- An intravenous injection can lead to seizures
Correct statements concerning bupivacaine include all of the following EXCEPT
It has low cardiotoxicity
