Neuromuscular Blocking Drugs

Question 1

Lidocaine is a local anaesthetic medication that is used to block pain sensations in a wide variety of superficial and invasive procedures. How does lidocaine stop us from feeling pain?

Answer 1

• inhibits action potentials
• so even if the body experiences pain the signal is not transmitted to the CNS

Question 2

Lidocaine is a local anaesthetic (means only a small part of the body is treated and patient is generally awake) medication that is used to block pain sensations in a wide variety of superficial and invasive procedures. Lidocaine is able to inhibit action potentials, therefore reducing the sensation of pain in the CNS. What is the mechanism of action of Lidocaine?

1 - enters cell, ionised, binds with K+ channels and keeps them closed
2 - enters cell, ionised, binds with Ca2+ channels and keeps them closed
3 - enters cell, ionised, binds with Na+ channels and keeps them closed
4 - enters cell, ionised, binds with Po+4 channels and keeps them closed

Answer 2

• able to pass into the cell
• due to lower pH inside cell Lidocaine is ionised and cannot leave the cell
• ionised lidocaine then binds with Na+ channels and keeps them closed

Question 3

Propofol is a general anaesthetic (means the whole body is treated and patient is generally unconscious) medication that is used to block pain sensations in a wide variety of procedures. What is the mechanism of action of propofol?

Answer 3

• modulation of the gama-aminobutyric acid, thus causing inhibition of neuronal cells
• bind with GABA-A receptors

Question 4

What are neuromuscular blocking agents that are commonly used in general (whole body with patient unconscious) anaesthesia?

Answer 4

• compete with acetylcholine and interfere with the transmission of nerve impulses
• affect the neuromuscular junction resulting in skeletal muscle relaxation

Question 5

Neuromuscular blocking agents that are commonly used in general (whole body with patient unconscious) anaesthesia compete with acetylcholine (ACh) and interfere with the transmission of nerve impulses, affecting the neuromuscular junction resulting in skeletal muscle relaxation. Rocuronium is a non-depolarising drug. What is the mechanism of action of Rocuronium?

Answer 5

• binds to same site as ACh on nicotinic receptors
• stops ion gated channels from opening
• no depolarisation occurs and muscle remains relaxed

Question 6

What do all non-depolarising drug names end in?

Answer 6

• ium like Rocuronium

Question 7

Neuromuscular blocking agents that are commonly used in general (whole body with patient unconscious) anaesthesia compete with acetylcholine (ACh) and interfere with the transmission of nerve impulses, affecting the neuromuscular junction resulting in skeletal muscle relaxation. Succinylcholine is a depolarising drug. What is the mechanism of action of Succinylcholine?

Answer 7

• bind to ion gated Na+ channels post-synapse
• Na+ channels open creating an action potential
• succinylcholine cannot be degraded so channels remain open and eventually desensitise and shut down
• post synapse eventually repolarises and muscle relaxes