Relaxant Health Dictionary

These drugs produce partial or complete paralysis of skeletal muscle (see under MUSCLE – Structure of muscle). Drugs in clinical use are all reversible and are used to help insert a breathing tube into the TRACHEA (endotracheal tube) during general ANAESTHESIA and ARTIFICIAL VENTILATION OF THE LUNGS. They may be broadly divided into depolarising and nondepolarising muscle relaxants. Depolarising muscle relaxants act by binding to acetylcholine receptors at the motor end-plate where nerves are attached to muscle cells, and producing a more prolonged depolarisation than acetylcholine, which results in initial muscle fasciculation (overactivity) and then ?accid paralysis of the muscle. The only commonly used depolarising drug is succinylcholine which has a rapid onset of action and lasts approximately three minutes. Non-depolarising muscle relaxants bind to the acetylcholine receptors, preventing acetylcholine from gaining access to them. They have a slower onset time and longer duration than depolarisers, although this varies widely between di?erent drugs. They are competitive antagonists and they may be reversed by increasing the concentration of acetylcholine at the motor end-plate using an anticholinesterase agent such as neostigmine. These drugs are broken down in the liver and excreted through the kidney, and their action will be prolonged in liver and renal failure. Other uses include the relief of skeletal muscle spasms in TETANUS, PARKINSONISM and spastic disorders. The drugs dantrolene and diazepam are used in these circumstances.... muscle relaxants

See: SEDATIVE. ... nerve relaxant

A group of drugs used to relieve muscle spasm and spasticity. Muscle-relaxant drugs are used mainly in the treatment of nervoussystem disorders such as multiple sclerosis and painful muscular conditions such as torticollis. They are occasionally used to relieve muscle rigidity caused by injury. Some types are used to cause temporary paralysis during surgery under general anaesthesia.Except for dantrolene, muscle-relaxant drugs partly block nerve signals that stimulate muscle contraction. Dantrolene interferes with the chemical activity in muscle cells needed for contraction.

The drugs may cause muscle weakness and drowsiness. In rare cases, dantrolene causes liver damage.... muscle-relaxant drugs

Drugs that are used to delay the premature delivery of a fetus. Beta2-adrenoceptor stimulants, such as salbutamol, relax the muscle of the uterus and may postpone labour for days or weeks in at-risk pregnancies of 24–33 weeks’ gestation. Delay of premature labour for up to 48 hours allows time for corticosteroid drugs to be given to the mother to help the fetal lungs to mature.... uterine muscle relaxants

an agent that reduces tension in voluntary muscles. Drugs such as *baclofen, *dantrolene, and *diazepam are used to relieve skeletal muscular spasms in various spastic conditions, parkinsonism, and tetanus. The drugs used to relax voluntary muscles during the administration of anaesthetics in surgical operations act by blocking the transmission of impulses at neuromuscular junctions. Nondepolarizing muscle relaxants, e.g. *atracurium besilate, cisatracurium, pancuronium, and rocuronium, bind to receptor sites normally occupied by acetylcholine; depolarizing muscle relaxants, e.g. *suxamethonium, mimic the action of acetylcholine but *depolarization is prolonged.... muscle relaxant