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Published on: September 20, 2019
[Muscle relaxants]
1Avdeling for anestesi, Oslo universitetssykehus, Aker 0514 Oslo, Norway. tom.heier@medisin.uio.no
Summary
Muscle relaxants, introduced in 1942, aid surgical relaxation by blocking nerve-muscle signals. While generally safe, some like suxamethonium have side effects, and optimal agents are still sought.
Area of Science:
- Anesthesiology
- Pharmacology
- Medical History
Context:
- Muscle relaxants have been integral to clinical anesthesia since 1942.
- Their development traces back to South American curare compounds, with d-tubocurarine isolated in 1935.
Purpose:
- To provide a comprehensive overview of muscle relaxant history.
- To detail their mechanisms of action.
- To discuss their current role in anesthetic practice.
Summary:
- Muscle relaxants, such as suxamethonium and curare derivatives, function by disrupting nerve-muscle signaling to induce skeletal muscle paralysis.
- They facilitate surgical procedures by providing muscle relaxation, an effect that can reduce the need for higher anesthetic doses.
- These agents do not possess anesthetic or analgesic properties and do not affect consciousness.
Impact:
- Muscle relaxants are generally safe when administered correctly, though suxamethonium carries risks of severe adverse events.
- Their use is common during anesthesia induction but less frequent during surgery due to the inherent muscle-relaxing effects of modern anesthetics.
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01:28Classification of Skeletal Muscle Relaxants
Skeletal muscle relaxants are a group of drugs that can reduce muscle stiffness and induce temporary paralysis to relieve pain. These agents can act centrally to reduce muscle tone or spasms in painful conditions such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), or spinal injuries; they are called antispasmodics or spasmolytics.
Peripherally acting skeletal muscle relaxants interfere with the neurotransmission at the neuromuscular end plate to induce paralysis during...
Peripherally acting skeletal muscle relaxants interfere with the neurotransmission at the neuromuscular end plate to induce paralysis during...
01:31Skeletal Muscle Relaxants: Therapeutic Uses
Skeletal muscle relaxants are used to relax muscle tone and alleviate painful muscle contractions. However, the choice of skeletal muscle relaxants depends on the duration of the surgical procedure in order to minimize potential side effects. Skeletal muscle relaxants like neuromuscular blocking agents [NMBAs] are commonly employed as adjuvants alongside general anesthetics in clinical settings. NMBAs are also used to maintain controlled ventilation during surgery of the larynx or pharynx as...
01:24Centrally Acting Muscle Relaxants: Therapeutic Uses
Centrally acting muscle relaxants reduce muscle tone and tension by interfering with the postsynaptic reflexes in the central nervous system.
Centrally acting drugs are classified into spasmolytic and antispasmodic drugs. Spasmolytic drugs such as baclofen, diazepam, and tizanidine inhibit spinal motor neurons and decrease muscle tone. Spasmolytic drugs are administered for severe and chronic spasms due to multiple sclerosis, cerebral palsy, stroke, and spinal cord and muscle injuries. However,...
Centrally acting drugs are classified into spasmolytic and antispasmodic drugs. Spasmolytic drugs such as baclofen, diazepam, and tizanidine inhibit spinal motor neurons and decrease muscle tone. Spasmolytic drugs are administered for severe and chronic spasms due to multiple sclerosis, cerebral palsy, stroke, and spinal cord and muscle injuries. However,...
01:09Peripherally and Centrally Acting Muscle Relaxants: A Comparison
Skeletal muscle relaxants can target the central nervous system [CNS] to reduce muscle tension or act directly at the neuromuscular junction to induce temporary paralysis. These two classes of muscle relaxants are called centrally acting muscle relaxants and peripherally acting muscle relaxants. They differ in their action, mechanism, administration route, and clinical uses.
Centrally acting muscle relaxants can be further divided into spasmolytic and antispasmodic drugs. Spasmolytic drugs,...
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01:21Skeletal Muscle Relaxants: Adverse Effects
Skeletal muscle relaxants are widely used for muscle paralysis and relieving pain following any muscle injury or stiffness. However, depending on the drug type, they can have adverse effects that range from mild to severe. Usually, nondepolarizing neuromuscular blockers have minimal side effects. For example, drugs like d-tubocurarine, cisatracurium, and rocuronium cause hypotension, whereas drugs like baclofen, when stopped abruptly, can lead to the recurrence of spastic conditions.
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Unlike...
01:26Directly Acting Muscle Relaxants: Dantrolene and Botulinum Toxin
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The binding of dantrolene to the RYR1...
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