Skeletal muscle relaxants/ antispastic drugs Flashcards
What type of drug is baclofen?
What pathway is that receptor on?
GABA receptor agonist
Baclofen binds to GABA receptors in the descending excitatory pathway, which reduces the release of glutamate.
What is the MoA of baclofen?
binds to GABA receptor in descending excitatory pathway, reducing release of glutamate and thus decreased skeletal muscle contraction
This is particularly useful for treating spasticity.
What conditions is baclofen used to treat?
- Spasticity in MS
- Spinal cord injury
- Cerebral palsy
What are common side effects of baclofen?
- Drowsiness
- Weakness
- Dizziness
- Risk of withdrawal if stopped abruptly
What should be monitored when a patient is on baclofen?
Renal function
What type of muscle relaxant is pancuronium?
Non-depolarizing muscle relaxant
or Non-depolarizing neuromuscular blocker
What is the receptor type and action of pancuronium?
Nicotinic M (Nm) receptor antagonist
It competitively blocks ACh receptors at the neuromuscular junction.
What is the primary use of pancuronium?
Induce skeletal muscle relaxation during surgery and intubation
In addition to surgery, when else is pancuronium used?
Electroconvulsive shock therapy
What is a notable trend regarding the usage of pancuronium?
Almost never used anymore
usually roc or vec or cis (all non-depolarizing)
What are some alternatives to pancuronium for muscle relaxation?
- Rocuronium
- Vecuronium
- Cisatracurium
All of these are non-depolarizing
What is the MoA of pancuronium?
“nondepolarizing because it is blocking action
Competitively blocks ACh receptors at the neuromuscular junction, leading to paralysis”
What type of muscle relaxant is succinylcholine?
Depolarizing muscle relaxant
Succinctly, it acts as an Nm receptor agonist.
What is the mechanism of action of succinylcholine?
It binds to the Nm receptor for a prolonged period, causing conformational change and inactivation, preventing twitch summation and sustained contraction
This leads to muscle relaxation.
What are the primary uses of succinylcholine?
- Rapid sequence intubation
- Short surgical procedures
It is especially useful in situations requiring quick muscle relaxation.
What are the risks associated with succinylcholine?
- Hyperkalemia
- Malignant hyperthermia
- Muscle fasciculations
It is contraindicated in burn injuries, neuromuscular disorders, or denervation injuries.
What type of drug is botulinum toxin?
ACh release inhibitor at the neuromuscular junction
It inhibits the fusion of vesicles to the neuron’s membrane.
What is the mechanism of action of botulinum toxins?
Blocks exocytosis of ACh by inhibiting vesicle fusion
This prevents muscle contraction at the neuromuscular junction.
What are the primary uses of botulinum toxins?
- Strabismus
- Facial wrinkles
- Migraines
It is used for both medical and cosmetic purposes.
What are the potential side effects of botulinum toxin injections?
- Injection site pain
- Localized muscle weakness
- Potential for systemic spread if improperly dosed
Care must be taken to avoid adverse effects.
What type of drug is dantrolene?
ryanodine receptor antagonist;
Inhibitor of Ca²⁺ release; muscle relaxant
It specifically inhibits Ca2+ release to prevent muscle contraction.
What are the primary uses of dantrolene?
- Malignant hyperthermia
- Neuroleptic malignant syndrome
- Spasticity
It is used in critical care situations to manage severe muscle contraction.
What are the risks associated with dantrolene?
- Hepatotoxicity
- Muscle weakness
- Drowsiness
Liver function must be monitored during treatment.
What is the MoA of dantrolene?
Dantrolene depresses excitation-contraction coupling in skeletal muscle by binding to the ryanodine receptor 1, and decreasing intracellular calcium concentration.
Ryanodine receptors mediate the release of calcium from the sarcoplasmic reticulum, an essential step in muscle contraction.
