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13 Cards in this Set
- Front
- Back
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Name some ester type local anaesthetics
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Benzocaine, cocaine, procaine, tetracaine |
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Name some amide type local anaesthetics
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Lidocaine, mepivacaine, prilocaine, bupivacaine, ropivacaine |
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Name some toxins with similar mechanism of action as local anaesthetics |
Saxitoxin, tetrodotoxin |
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What are the indications for local anaesthetics? |
Surface anaesthesia Infiltration anaesthesia Nerve block Spinal anaesthesia Epidural anaesthesia IV regional anaesthesia |
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What is the mechanism of action of local anaesthetics?
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Local anaesthetics work by reversibly blocking voltage-gated Na+ channels. They block these channels from the intracellular side. |
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Why is it an advantage that all local anaesthetics are weak bases? |
Because this causes them to be "trapped" in more acidic environments like the intracellular space. This is called ion trapping. |
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What do we mean when we say that the action of local anaesthetics is use-dependent? |
It means that the anaesthetic effect is increased in more active nerve fibres. |
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What causes the local anaesthetic effect to stop? |
The anaesthetic effect stops when the local anaesthetic is absorbed from the tissue they’re applied to into the plasma. |
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Why do we give vasoconstrictors with local anaesthetics? |
Local vasoconstrictors slow down the absorption of the local anaesthetic into the plasma. This increases the duration of action. |
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How are ester type local anaesthetics eliminated?
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By hydrolysis by pseudocholinesterase |
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How are amide type local anaesthetics eliminated? |
By metabolism by CYP450 |
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What are the side effects of local anaesthetics? |
Tremor, confusion, paralysis. Negative heart effects Allergic reactions (only ester types) |
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Which local anaesthetic is the most used topically? |
Lidocaine |
