Skeletal Muscle Relaxants Flashcards
What are muscle spasms?
Muscle spasms refer to sudden, involuntary contractions or tightening of muscles. These contractions can be brief and intense, causing a visible or palpable twitch or jerk in the affected muscle.
Describe the duration and characteristics of muscle spasms
Duration: Muscle spasms are typically of short duration, lasting only a few seconds to minutes.
Characteristics: Muscle spasms often involve a specific muscle or muscle group and may be painful. They can occur spontaneously or may be triggered by certain movements or activities.
What are the causes of muscle spasms?
Causes: Common causes of muscle spasms include muscle fatigue, dehydration, electrolyte imbalances (such as low levels of potassium, calcium, or magnesium), and overuse or strain of muscles.
What is spasticity of muscles?
Definition: Spasticity is a condition characterized by continuous muscle stiffness, istion the comestion between the little us sisten on and
spinal cord) and the muscles.
Outline the duration and characteristics of spasticity
Duration: Unlike muscle spasms, spasticity involves a sustained increase in muscle tone and can be present for an extended period.
•Characteristics: Spasticity altects muscles on a more global level and can involve multiple muscle groups. It often leads to stiffness, and reduced range of motion and may interfere with coordinated movements
What are skeletal muscle relaxants?
• Skeletal muscle relaxants are drugs that act peripherally at neuromuscular junction/ muscle fibre itself or centrally in the cerebrospinal axis to reduce muscle tone and/or cause paralysis.
• A muscle relaxants is a drug that affects skeletal muscle function and decreases the muscle tone. It may be used to improve symptoms such as muscle spasms, pain, and hyperreflexia.
List the neuromuscular blocker drugs
- Non-depolarizing (competitive) include D tubocurarine ; Pancuronium; Vecuronium ; Atracurium ; Mivacurium ; rocuronium
- Depolarizing (non-competitive) include Succinylcholine ; Decamethomium
List the spasmolytic drugs
- Centrally acting include Diazepam ; Chlorzoxazone ; Tizanidine ; Baclofen
- Directly acting include dantrolene
What is the MoA of non-depolarizing neuromuscular blockers?
Non-depolarizing drugs block the action of acetylcholine at the neuromuscular junction by competitively binding to the nicotinic acetylcholine receptors on the motor end plate. They do not cause depolarization of the muscle cell membrane
What is the effect of non-depolarizing neuromuscular blockers on muscle contraction?
These drugs result in muscle relaxation by preventing the normal transmission of nerve impulses to the muscles. They do so by inhibiting the binding of acetylcholine, which is necessary for muscle contraction.
What is the effect of depolarizing neuromuscular blockers on muscle contraction?
While depolarizing, they also persist in their activity, preventing the muscle from repolarizing and leading to sustained muscle paralysis. This is known as “phase I block.”
What are the reversal agents of non-depolarizing neuromuscular blockers?
The effects of non-depolarizing drugs can be reversed by acetylcholinesterase inhibitors, such as neostigmine, which increase the concentration of acetylcholine at the neuromuscular junction.
Anti-cholinestrases
(neostigmine,
edrophonium)
which preserve
acetylcholine
are used to reverse
the effect of
d-tubocurarine
What is the MoA of depolarizing neuromuscular blockers?
Depolarizing drugs, on the other hand, mimic the action of acetylcholine by initially binding to the nicotinic receptors and causing depolarization of the muscle cell membrane. However, unlike acetylcholine, these drugs are resistant to degradation by acetylcholinesterase.
What is the duration of action of depolarizing neuromuscular agents?
Depolarizing drugs have a relatively short duration of action due to their metabolism, but in some cases, prolonged effects may occur, leading to a phase II block characterized by resistance to further depolarization.
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