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. 
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            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
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            ]

            Text:
            onduction rate. 
3. Force of contraction. 
4. Decreased cardiac output. 
5. Circulatory collapse (see Table 2.3). 
• 
The depressant action of LA is used in management of  ventricular tachycardia 
and ventricular fibrillation (hyperexcitable myocardium) e.g Lidocaine. 
• 
Blood levels of lidocaine:  
1. One or two dental cartridges (0.5 to 2 μg/mL) -> not associated with cardio 
depressant activity. 
2. Increasing it slightly-> nontoxic and is associated with anti-dysrhythmic actions. 
3. Therapeutic blood levels for antidysrhythmic activity -> from 1.8 to 6 μg/mL. 
 
Box 2.3 summarises the CNS and cardiovascular effects of increasing local 
anaesthetic blood levels, direct Action on the Peripheral Vasculature {Reference to 
the effect on all blood vessels that exist outside the heart} 
 
 
 
• 
Cocaine is the only local anaesthetic drug that consistently produces 
vasoconstriction at commonly used dosages. 
• 
All other injectable local anaesthetics produce a peripheral vasodilation through 
relaxation of smooth muscle in the walls of blood vessels leading to:  
1. Increased blood flow to and from the site of LA deposition. 
2. Increasing the rate of drug absorption.  
3. Leading to decreased depth and duration of LA action.  
4. Increasing bleeding in treatment area.  
5. Increasing LA blood levels. 
6. Increasing systemic toxicity. 
7. Hypotension.  
• Certain local anaesthetics such as bupivacaine, and to a lesser degree 
ropivacaine and etidocaine may precipitate fatal ventricular fibrillation. 
 
Local Tissue Toxicity 
• 
longer acting LA cause more localised skeletal muscle damage than short acting 
LA. 
• 
IM and intraoral injection of articaine, lidocaine, mepivacaine, prilocaine, 
bupivacaine, and etidocaine can produce skeletal muscle alterations. 
• 
Changes are reversible.  
• 
Muscle regeneration occurs within 2 weeks after LA administration.  
 
Respiratory System 
• 
LA affects respiration: 
1. At non-overdose levels -> direct relaxant action on bronchial smooth 
muscle. 
2. At overdose levels -> may produce respiratory arrest as a result of 
generalised CNS depression.  
 
Miscellaneous Actions 
Drug Interactions 
• The conjoint use of LA and drugs that share a common metabolic pathway can 
produce adverse reactions:  
1. Drugs that induce the production of hepatic microsomal enzymes (e.g., 
barbiturates) -> may alter the rate at which amide local anaesthetics are 
metabolised. (Increased hepatic microsomal enzyme induction increases 
the rate of metabolism of the LA). 
2. Both ester LA and succinylcholine require plasma pseudocholinesterase 
for hydrolysis -> Prolonged apnea may result from concomitant use of 
these drugs. 
  
Malignant Hyperthermia  
• 
A pharmacogenic disorder in which a genetic variant in an individual alters that 
person’s response to certain drugs. 
• 
Acute clinical manifestations include:  
1. Tachycardia. 
2. Tachypnea. 
3. Unstable blood pressure. 
4. Cyanosis. 
5. Respiratory and metabolic acidosis. 
6

            Quiz: