Relaxant, skeletal muscle

Historical Inhalation Agents. Diethyl ether produces excellent surgical anesthesia, but it is flammable (see Ethers). Chloroform is a nonflammable, sweet smelling, colorless Hquid which provides analgesia at nonanesthetic doses and can provide potent anesthesia at 1% (see Chlorocarbons AND CHLOROHYDROCARBONs). However, a metabohte causes hepatic cell necrosis. Tdlene, a nonflammable colorless Hquid, has a slower onset and recovery and a higher toxicity and chemical reactivity than desirable. Cyclopropane is a colorless gas which has rapid induction (2 —3 min) and recovery characteristics and analgesia is obtained in the range of 3—5% with adequate skeletal muscle relaxation (see Hydrocarbons). The use of cyclopropane has ceased, however, because of its flammabiHty and marked predisposition to cause arrhythmias. 

Skeletal muscle relaxant. A drug that decreases the tone of voluntary muscles. 

Therapeutic Function Skeletal Muscle Relaxant Chemical Name N,N -DiallYlnortoxiferinium DIchloride... 

Therapeutic Function Skeletal muscle relaxant Chemical Name 5-chloro-2(3H)-benzoxazolone Common Name 5-chloro-2-hydroxybenzoxazole Structural Formula ... 

Therepeutic Function Analgesic, skeletal muscle relaxant Chemical Name a-[ (2-Pyridinylemino)methyl] benzenemethenol Common Name Feny ram idol Structural Formula ... 

Therapeutic Function Skeletal muscle relaxant uricosuric Chemical Name 5-Chloro-2-benzoxazolamine Common Name —... 

The mode of action of many skeletal muscle relaxants, for example carisoprodol (Soma), baclofen (Lioresal), and chlorzoxazone (Paraflex), is not clearly understood. Many of tiiese dragp do not directly relax skeletal muscles, but dieir ability to relieve acute painful musculoskeletal conditions may be due to their sedative action. Cyclobenzaprine (Flexeril) appears to have an effect on muscle tone, tiius reducing muscle spasm. 

Skeletal muscle relaxants are used in various acute, painful musculoskeletal conditions, such as muscle strains and back pain. 

Drowsiness is the most common reaction seen with the use of skeletal muscle relaxants. Additional adverse reactions are given in die Summary Drug Table Drugp Used to Treat Musculoskeletal Disorders. Some of the adverse reactions tiiat may be seen with the administration of diazepam include drowsiness, sedation, sleepiness, letiiargy, constipation or diarrhea, bradycardia or tachycardia, and rash. 

The skeletal muscle relaxants are contraindicated in patients with known hypersensitivity. Baclofen is contraindicated in skeletal muscle spasms caused by rheumatic disorders. Carisoprodol is contraindicated in patients with a known hypersensitivity to meprobamate. Cyclobenzaprine is contraindicated in patients with a recent myocardial infarction, cardiac conduction disorders, and hyperthyroidism, hi addition, cyclobenzaprine is contraindicated within 14 days of the administration of a monoamine oxidase inhibitor. Oral dantrolene is contraindicated in patients with active hepatic disease and muscle spasm caused by rheumatic disorders and during lactation. See Chapter 30 for information on diazepam. 

There is an increased central nervous system (CNS) depressant effect when the skeletal muscle relaxants are administered with other CNS depressants, such as alcohol, antihistamines, opiates, and sedatives. There is an additive anticholinergic effect when cyclobenzaprine is administered with other drugs with anticholinergic effects (eg, antihistamines, antidepressants, atropine, haloperidol). See Chapter 30 for information on diazepam. 

SKELETAL MUSCLE RELAXANTS. The nurse gives these drug with food to minimize gastrointestinal distress, hi addition to drug therapy, rest, physical therapy, and other measures may be part of treatment. 

SKELETAL MUSCLE RELAXANTS. These drugs may cause drowsiness. Because of the risk of injury, the nurse evaluates the patient carefully before allowing the patient to ambulate alone. If drowsiness does occur, assistance with ambulatory activities is necessary. If drowsiness is severe, the nurse notifies the primary health care provider before the next dose is due... 

The anesthesiologist selects the anesthetic drug that will produce safe anesthesia, analgesia (absence of pain), and in some surgeries, effective skeletal muscle relaxation. General anesthesia is most commonly achieved when the anesthetic vapors are inhaled or administered intravenously (IV). Volatile liquid anesthetics produce anesthesia when their vapors are inhaled. Volatile liquids are liquids that evaporate on exposure to air. Examples of volatile liquids include halothane, desflurane, and enflurane. Gas anesthetics are combined with oxygen and administered by inhalation. Examples of gas anesthetics are nitrous oxide and cyclopropane. 

An anesthetic gas, cyclopropane has a rapid onset of action and may be used for induction and maintenance of anesthesia Skeletal muscle relaxation is produced with full anesthetic doses. Cyclopropane is supplied in orange cylinders. Disadvantages of cyclopropane are difficulty in detecting the planes of anesthesia, occasional laryngospasm, cardiac arrhythmias, and postanesthesia nausea, vomiting, and headache Cyclopropane and oxygen mixtures are explosive, which limits the use of this gas anesthetic. 

Enflurane (Ethrane) is a volatile liquid anesthetic that is delivered by inhalation. Induction and recovery from anesthesia are rapid. Muscle relaxation for abdominal surgery is adequate, but greater relaxation may be necessary and may require the use of a skeletal muscle relaxant. Enflurane may produce mild stimulation of respiratory and bronchial secretions when used alone Hypotension may occur when anesthesia deepens. 

Halothane (Fluothane) is a volatile liquid given by inhalation for induction and maintenance of anesthesia Induction and recovery from anesthesia are rapid, and the depth of anesthesia can be rapidly altered. Halothane does not irritate the respiratory tract, and an increase in tracheobronchial secretions usually does not occur. Halothane produces moderate muscle relaxation, but skeletal muscle relaxants may be used in certain types of surgeries. This anesthetic may be given with a mixture of nitrous oxide and oxygen. 

Methoxyflurane (Penthrane), a volatile liquid, provides analgesia and anesthesia It is usually used in combination with nitrous oxide but may also be used alone. It does not produce good muscle relaxation, and a skeletal muscle relaxant may be required. 

The various skeletal muscle relaxants that may be used during general anesthesia are listed in Table 35-3. These drugp are administered to produce relaxation of the skeletal muscles during certain types of surgeries, such as those involving the chest or abdomen. They may also be used to facilitate the insertion of an endotracheal... 

One use of skeletal muscle relaxants as part of general anesthesia is to. ... 

Skeletal Muscle Relaxant Combinations Carisoprodol Compound—carisoprodol, aspirin Mexaphen—chlorzoxazone, acetaminophen Lobac—salicylamide, phenyltoloxamine, acetaminophen Norgesic Fbrte—orphenadrine citrate, aspirin, caffeine Norgesic—orphenadrine citrate, aspirin, caffeine Robaxisal—methocarbamol, aspirin Sodol Compound—carisoprodol, aspirin Soma Compound—carisoprodol, aspirin... 

Reduction of the exocylic double bond and inclusion of the side chain nitrogen in a piperidine ring leads to a compound (19) which exhibits skeletal muscle relaxant activity. Its one step synthesis begins with reaction of thioxanthene (17) with phenyl sodium... 

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