Question
(
(a) Classify peripherally acting skeletal muscle relaxants.
( 4 mark(s) (b) Mention one centrally acting skeletal muscle relaxant with its mechanism of action
and indications for use. 4 mark(s)
Q3 8 marks Short Essays ★ ✓
Answer
a) Classification of peripherally acting skeletal muscle relaxants
Peripherally acting relaxants act at the neuromuscular junction, falling into two mechanistically distinct groups:
Type Mechanism Examples Competitive (non-depolarizing) block Occupy the nicotinic receptor without activating it, blocking ACh — surmountable with anticholinesterases d-Tubocurarine, Pancuronium, Vecuronium, Atracurium Depolarizing block Persistently depolarize the endplate, inactivating surrounding Na⁺ channels Succinylcholine (Suxamethonium)
b) One centrally acting muscle relaxant — Baclofen
Mechanism : a GABA-B receptor agonist, acting at the spinal cord to inhibit excitatory neurotransmitter release from afferent nerve terminals, reducing the reflex arc responsible for spasticity, without directly acting on the neuromuscular junction.
Indications : upper motor neurone spasticity — multiple sclerosis, spinal cord injury, cerebral palsy.
1 Skeletal Muscle Relaxants
Other Years Asked
1 Read the clinical problem and answer the following questions: 30 years old man was admitted
in emergency ward with acute abdominal pain. After diagnosed with acute appendicitis, he was
taken for surgery. On the operation table, after administration of a skeletal muscle relaxant,
patient developed difficulty in breathing and went in for apnoea. 2015 September (Supplementary) (2010 Scheme) Essay · 6 marks 2 Read the clinical problem and answer the following questions: A 50 years old man was
administered succinylcholine for endotracheal intubation. The patient developed
prolonged muscle paralysis and apnea. (2+2+2)
What could be the cause of apnea in this patient
How will you treat the apnea
Name two muscle relaxants that you can use in this patient in future 2021 May (Supplementary) (2010 Scheme) Essay · 6 marks 3 Atracurium 2020 February (Supplementary) (2010 Scheme) Short Note · 3 marks 4 Mechanism of action of diazepam 2014 March (2010 Scheme) Short Answer · 1 mark 5 Mechanism of action of pancuronium. 2016 October (Supplementary) (2010 Scheme) Short Answer · 1 mark 6 Diazepam 2023 March (Supplementary) (2010 Scheme) Short Answer · 1 mark 7 Flumazenil 2013 April (2010 Scheme) Short Answer · 1 mark 8 Centrally acting muscle relaxants 2015 September (Supplementary) (2010 Scheme) Short Answer · 1 mark 9 Mechanism of action of diazepam. 2016 February (2010 Scheme) Short Answer · 1 mark 10 Mechanism of action of dantrolene sodium. 2014 September (Supplementary) (2010 Scheme) Short Answer · 1 mark 11 Dantrolene sodium in malignant hyperthermia 2023 March (Supplementary) (2010 Scheme) Short Answer · 1 mark 12 d-Tubocurarine 2021 May (Supplementary) (2010 Scheme) Short Answer · 1 mark 13 Dantrolene in malignant hyperthermia. 2025 August (Supplementary) (2010 Scheme) Short Answer · 1 mark 14 Diazepam 2024 March (Supplementary) (2010 Scheme) Short Answer · 1 mark 15 Peripherally acting skeletal muscle relaxants 2013 September (Supplementary) (2010 Scheme) Short Answer · 1 mark 16 Uses of diazepam 2017 February (2010 Scheme) Short Answer · 1 mark 17 Competitive neuromuscular blockers 2018 July (Supplementary) (2010 Scheme) Short Answer · 1 mark 18 Dantrolene in malignant hyperthermia 2019 February (2010 Scheme) Short Answer · 1 mark 19 Centrally acting skeletal muscle relaxants 2022 May (Supplementary) (2010 Scheme) Short Answer · 0.3 marks 20 Depolarizing neuromuscular blocking agents 2022 October (Supplementary) (2010 Scheme) Short Answer · 0.3 marks 21 Skeletal muscle relaxants 2022 July (Supplementary) (2019 Scheme) Short Answer · 0.2 marks 22 Centrally acting skeletal muscle relaxants 2024 March (Supplementary) (2019 Scheme) Short Answer · 0.2 marks 
