Skeletal Muscle Drugs

Front 1

tubocurarine (curare)

Back 1

Class: Nondepolarising NM blocker
Action: competitive inhibitor of Nic-NMJ RR (Nic-NMJ antagonist). Ganglionic blockade at very high doses. Causes release of histamine.
Tx: adjuvant to surgical anaesthesia.
Side Effects: due to histamine, vasodilation, hypotension, bronchial/salivary secretion, bronchospasm.
Contrain.: aminoglycoside antibiotics; will compete for neuronal Ca2+, exacerbating NMJ transmission.
Notes: two 4° amines; can't cross BBB.

Front 2

gentamycin

Back 2

Class: aminoglycoside antibiotic
Action:
Tx:
Side Effects:
Contrain.: tubocurarine; can inhibit NM transmission by competing for neuronal Ca2+
Notes:

Front 3

Halothane

Back 3

Class: general anaesthetic
Action: stabilises the post-synaptic mem. potential.
Tx:
Side Effects:
Contrain.:
Notes: synergistic with tubocurarine

Front 4

isoflurane

Back 4

Class: general anaesthetic
Action: stabilises the post-synaptic mem. potential.
Tx:
Side Effects:
Contrain.:
Notes: synergistic with tubocurarine

Front 5

pancuronium

Back 5

Class: Nondepolarising NM blocker
Action: no histamine release, some cardiac blockade.
Tx:
Side Effects:
Contrain.:
Notes: 6x potency of tubocurarine. Long duration. Renal elimination.

Front 6

vecuronium

Back 6

Class: Nondepolarising NM blocker
Action: no histamine release.
Tx:
Side Effects:
Contrain.:
Notes: liver metabolised; int. duration, 6x potency of tubocurarine.

Front 7

rocuronium

Back 7

Class: Nondepolarising NM blocker
Action: no histamine release.
Tx: tracheal intubation
Side Effects:
Contrain.:
Notes: lower potency, rapid onset (use higher dose to speed onset), int. duration.

Front 8

succinylcholine

Back 8

Class: depolarising blocker
Action: depolarises the endplate, causing fast Na+ ch. to go to inactive state. Prolonged exposure may desensitise Nic-NMJ.
Tx: mm relaxation during surgery; laryngo-, broncho-, oesophagoscopy; electroshock therapy.
Side Effects:
Contrain.:
Notes:

Front 9

dantrolene

Back 9

Class: Spasmolytics
Action: blocks Ca2+ release from the SR
Tx: malignant hyperthermia due to halothane+succinylcholine in pts. with mutant SR.
Side Effects: weakness, sedation, hepatitis (rare).
Contrain.:
Notes: acts mainly on sk. mm., little effect on cardiac or smooth mm.

Front 10

botulinum Toxin

Back 10

Class: Presynaptic Release Blocker
Action: cleaves SNARE complex, inhibiting ACh vesicle fusion.
Tx: blepharospasm (eyelids); strabismus; Meige's Syndrome (hemifacial spasm); spasmodic torticollis; spasmodic dysphonia (laryngeal spasms); hyperhidrosis (excessive sweating); cosmetic.
Side Effects: hypersensitivity, dry mouth/swallowing, mm weakness, diplopia, ptosis, mydriasis, constipation.
Contrain.:
Notes:

Front 11

4-aminopyridine

Back 11

Class: NM stimulant
Action: blocks K+ ch., delaying repolarisation and prolonging AP. ↑s ACh release.
Tx: LEMS
Side Effects:
Contrain.:
Notes:

Front 12

prednisolone

Back 12

Class: steroid
Action: inhibits Ab production.
Tx: Myasthenia Gravis
Side Effects:
Contrain.:
Notes:

Front 13

azathioprine

Back 13

Class: immunosuppressant
Action:
Tx: myasthenia gravis
Side Effects:
Contrain.:
Notes:

Front 14

baclofen (Lioresal)

Back 14

Class: Spasmolytics
Action: stimulates GABA-B RR, resulting in activating K+ ch. and blocking Ca2+ chh. Causes hyperpolarisation and ↓'d excitability. Interferes with CNS release of excitatory ntms.
Tx: spinal spasticity, spasticity due to MS.
Side Effects: severe drowsiness.
Contrain.:
Notes:

Front 15

diazepam (Valium)

Back 15

Class: Spasmolytics; sedative/hypnotic
Action: GABA-A R activator; blocks presynaptic terminal.
Tx: mm spasms
Side Effects: sedation
Contrain.:
Notes:

Front 16

Cyclobenzaprine (Flexeril)

Back 16

Class: spasmolytic; nonspecific central depressant
Action: depresses CNS polysynaptic reflexes.
Tx: mm spasm due to local trauma/strain.
Side Effects:
Contrain: spasm from cerebral palsy or spinal cord injury.
Notes: dry mouth, sedation, dizziness.