Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
                    "explanation": "EXPLAIN WHY THE ANSWER IS CORRECT"

            ]

            Text:
            t compound in the 
urine (because they are hydrolyzed almost completely in the plasma). 
• 
Amides are present in the urine as the parent compound in a greater percentage 
than the esters, because of their complex process of biotransformation). 
• 
Patients with significant renal impairment are unable to eliminate the parent local 
anaesthetic compound so:  
1. Elevated blood levels.  
2. Increased potential for toxicity. 
• 
So 
patients 
undergoing 
renal 
dialysis 
and 
those 
with 
chronic 
glomerulonephritis or pyelonephritis represent a relative contraindication.  
 
Systemic Actions of Local Anesthetics  
• 
Most of the systemic actions of local anaesthetics are related to their blood or 
plasma level in a target organ (CNS, CVS). 
• 
The higher the blood level, the greater will be the clinical action.  
• 
Local anaesthetics are absorbed from their site of administration into the 
circulatory system, which effectively dilutes them and carries them to all cells of 
the body. 
• 
The blood level of the local anaesthetic depends on:  
1. Its rate of uptake from the site of administration into the circulatory system. 
2. The rate of distribution in tissue and biotransformation (in the liver). 
3. The elimination of the drug from the blood. 
 
Central Nervous System: 
• 
Local anaesthetics cross the blood-brain barrier. 
• 
Pharmacological action on CNS -> Depression. 
• 
At low (non-toxic) blood levels -> no CNS effects.  
• 
At higher (toxic) levels, ---> Generalised tonic-clonic convulsions.  
• 
Between these two extremes exists a spectrum of other signs and symptoms 
(see Box 2.2)  
 
• 
Anticonvulsant Properties: 
• 
The “classic” overdose reaction to a local anaesthetic is a generalised tonic-
clonic convulsion. 
• 
Some local anaesthetics (e.g., procaine, lidocaine, mepivacaine, prilocaine, and 
even cocaine) have anticonvulsant properties that occur at a blood level below 
that at which the same drug produce seizure activity.  
• 
Lidocaine is the most promising anticonvulsant among other LA agents.  
 
Mechanism of Anticonvulsant Properties of Local Anesthetics: 
• 
Local anaesthetics raise the seizure threshold by:  
1. Decreasing the excitability of neurons in the epileptic focus. 
2. Preventing or terminating seizure. 
Pre-convulsive Signs and Symptoms 
• 
Occurs due to increase in the blood level of the local anaesthetic to above its 
therapeutic level.  
• 
With lidocaine, this phase is observed at a level between 4.5 and 7 μg/ mL in the 
average normal healthy patient. 
• 
Initial clinical signs and symptoms of CNS toxicity are usually excitatory in nature 
(see Box 2.2). 
• 
Lidocaine and procaine frequently produce mild sedation or drowsiness (more 
common with lidocaine). 
• 
If sedation is observed during the first 5 to 10 minutes after intraoral 
administration of a local anaesthetic, it should warn the clinician of a rising local 
anaesthetic blood level and the possibility of a generalised convulsive episode. 
Convulsive

            Quiz: