Question:medium
Which muscle relaxant increases intracranial pressure?
Which muscle relaxant increases intracranial pressure?
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Suxamethonium's fasciculations raise afferent traffic and cerebral blood flow before paralysis, unlike the non depolarising agents.
Updated On: Jul 8, 2026
- Mivacurium
- Atracurium
- Suxamethonium
- Vecuronium
Show Solution
The Correct Option is C
Solution and Explanation
Step 1: Recall how each relaxant blocks the neuromuscular junction.
Vecuronium, atracurium, and mivacurium sit on the receptor and simply stop acetylcholine from acting, so muscle goes straight to weakness. Suxamethonium instead switches the receptor on first, which is why it is called a depolarising blocker.
Step 2: Trace the fasciculation to the brain.
The brief opening of receptors by suxamethonium fires off muscle spindles all over the body. This extra sensory input travels to the central nervous system and briefly increases neuronal activity and cerebral blood flow.
Step 3: See the pressure effect.
More cerebral blood flow inside a closed skull means a rise in intracranial pressure, even if only for a couple of minutes. This matters most in patients who already have swelling or a mass lesion, where the pressure is already close to its limit.
Step 4: Confirm the other three stay neutral.
Because mivacurium, atracurium, and vecuronium never trigger fasciculations, they do not produce this afferent surge, so intracranial pressure is not pushed up by them.
Step 5: Conclude.
\[ \boxed{\text{Suxamethonium}} \]
Vecuronium, atracurium, and mivacurium sit on the receptor and simply stop acetylcholine from acting, so muscle goes straight to weakness. Suxamethonium instead switches the receptor on first, which is why it is called a depolarising blocker.
Step 2: Trace the fasciculation to the brain.
The brief opening of receptors by suxamethonium fires off muscle spindles all over the body. This extra sensory input travels to the central nervous system and briefly increases neuronal activity and cerebral blood flow.
Step 3: See the pressure effect.
More cerebral blood flow inside a closed skull means a rise in intracranial pressure, even if only for a couple of minutes. This matters most in patients who already have swelling or a mass lesion, where the pressure is already close to its limit.
Step 4: Confirm the other three stay neutral.
Because mivacurium, atracurium, and vecuronium never trigger fasciculations, they do not produce this afferent surge, so intracranial pressure is not pushed up by them.
Step 5: Conclude.
\[ \boxed{\text{Suxamethonium}} \]
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