Muscle relaxants cyclobenzaprine

Figure 34-10 Structure of some tricyclic antidepressants and the muscle relaxant cyclobenzaprine,...

The client is diagnosed with low back pain and is prescribed the muscle relaxant cyclobenzaprine (Flexeril). Which instructions should the clinic nurse teach the client ... 

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. 

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. 

Where pain is worsened by muscle spasm, oral muscle relaxants may serve as a useful adjunct to therapy.25 These agents include baclofen, metaxalone, methocarbamol, carisoprodol, and cyclobenzaprine. Muscle relaxants may decrease spasm and stiffness associated with either acute or chronic musculoskeletal disorders. These agents should be used with caution because they all may cause sedation, especially in combination with alcohol or narcotic analgesics. 

Centrally acting muscle relaxants are also widely used (baclofen, cyclobenzaprin, carisoprodol, methocarbamol, chlorphenesin, chlorzoxazone, orphenadrine, and... 

Geriatric Considerations - Summary Cyclobenzaprine is a skeletal muscle relaxant which is structurally related to the tricyclic antidepressants with anticholinergicprop-erties and it is very sedating. It is used for acute muscle pain and should not be used chronically. Its usefulness in the older adult is limited by its potential to cause adverse effects. 

Muscle relaxants and antispasmodics methocarbamol (Robaxin), carisoprodol (Soma), chlorzoxazone (Paraflex), metaxalone (Skelaxin), cyclobenzaprine (Flexeril), and oxybutynin (Ditropan) Do not consider the extended-release Ditropan XL Most muscle relaxants and antispasmodic drugs are poorly tolerated by elderly patients, because these cause anticholinergic adverse effects, sedation, and weakness. Additionally, their effectiveness at doses tolerated by elderly patients is questionable. High... 

It is not clear, however, exactly how these drugs inhibit neurons involved in the polysynaptic pathways. There is preliminary evidence that one of these compounds (cyclobenzaprine) might block serotonin receptors on spinal interneurons, thereby decreasing the excitatory influence of serotonin on alpha motor neuron activity.50,55 Although this effect has been attributed to cyclobenzaprine in animals (rats), the effect of this drug and other muscle relaxants in humans remains to be determined. 

Kobayashi H, Hasegawa Y, Ono H. Cyclobenzaprine, a centrally acting muscle relaxant, acts on descending serotonergic systems. EurJ Pharmacol. 1996 311 ... 

Cyclobenzaprine, a tricyclic amine structurally very similar to amitriptyline (see Figure 34-10), is used as a centrally acting skeletal muscle relaxant. Like amitriptyline, cyclobenzaprine causes sedation, produces central and peripheral muscarinic blockade, and potentiates adrenergic actions. In overdose, cyclobenzaprine may cause a typical anticholinergic toxidrome and cardiac arrhythmias, hypotension, and coma. However, cyclobenzaprine overdose is not as frequent nor as lethal as amitriptyline overdose. 

Cyclobenzaprine is structurally closely related to the tricyclic antidepressants (see later) and therefore shares many of their adverse reactions. These include drowsiness (CNS effects), dry mouth (anticholinergic effects), and dizziness. The potential for serious interactions with MAO inhibitors also exists. Nevertheless, the drug s centrally acting skeletal muscle relaxation is useful for short-term treatment of local muscle spasms. 

Cyclobenzaprine (10 mg t.i.d.) is a centrally acting skeletal muscle relaxant and is indicated as an adjunct to rest and physical therapy for relief of muscular spasm associated with injury related to painful musculoskeletal conditions. However, cyclobenzaprine is not effective in spasticity associated with cerebral or spinal cord injury. Cyclobenzaprine is structurally related to tricyclic antidepressants possessing sedative and anticholinergic properties. Therefore, cyclobenzaprine should be used cautiously in individuals with angle-closure glaucoma and urinary retention due to obstruction or prostatic hypertrophy. Because it causes drowsiness and blurred vision, it should be used carefully when alermess is required. 

Cyclobenzaprine is a centrally acting skeletal muscle relaxant that relieves skeletal muscle spasms of local origin without interfering with muscle function by acting within the CNS at the brain stem. Structurally and pharmacologically related to tricyclic antidepressants, cyclobenzaprine is indicated in the relief of muscle spasms associated with acute painful musculoskeletal conditions. 

The mechanism of action of cyclobenzaprine is thought to result from an increase in stimulation of central a2 receptors and subsequent decrease in noradrenergic activity. New evidence, however, suggests that the antagonist actions of the drug at 5-HT, receptors are responsible for the muscle relaxation effect. 

Cyclobenzaprine hydrochloride belongs to the class of centrally acting muscle relaxant and is chemically related to the tricyclic antidepressants. It is mostly employed for the symptomatic relief of muscle spasm. 

Cyclobenzaprine (Flexeril) [Skeletal Muscle Relaxant/ANS A9ent] Uses Relief of muscle spasm Action Cend ally acting skeletal muscle i elaxant i educes tonic somadc motor aedvity Dose 5-10 mg PO bid-qid (2-3 wk max) Caution [B, ] Shai es tlie toxic potendal of tlie TCAs urinary hesitancy, NAG Contra Do not use concomitantly or w/in 14 d of MAOIs hyperthyroidism heari faihue airhythmias Disp Tabs SE Sedadon andcholinergic effects Interactions T Effects of CNS depi-ession W/ CNS depi-essants, TCAs, barbiturates, EtOH T risk of HTN convulsions W/ MAOIs EMS Use caudon w/ other CNS depi-essants concurrent EtOH use can T CNS depi ession OD May cause N/V,... 

Tricyclic antidepressants are commoniy taken in overdose by suicidal patients and represent a major cause of poisoning hospitaiizations and deaths. Currently available tricyclic antidepressants are described in Table 11-7. Amitriptyline is also marketed in combination with chlordiazepoxide (Limbitrol ) or perphenazine (Etrafon or Tria-viF ). Cyclobenzaprine (FlexerilTW), a centrally acting muscle relaxant (see p 339), is structurally related to the tricyclic antidepressants but exhibits minimal cardiotoxic and variable CNS effects. Newer, noncyclic antidepressants are discussed on p 88. Monoamine oxidase inhibitors are discussed on page 269. 

B. Specific drugs and antidotes. There are no specific antidotes. Flumazenll (see p 446) Is a specific antagonist of benzodiazepine receptors, and would not be expected to cross-react with skeletal muscle relaxants or other sedative agents. While physostigmine may reverse anticholinergic symptoms associated with cyclobenzaprine and orphenadrine overdose. It Is not generally needed and may potentially cause seizures. 

Know the mechanism of action of your muscle relaxant. If the patient is already taking tramadol or tapentadol as well as amitriptyline, consider your rationale for adding a third agent with serotonergic activity such as cyclobenzaprine, as well as the increased risk of serotonin syndrome. Do not use cyclobenzaprine within 2 weeks of the last dose of an MAOI. Some MAOIs include isocarboxazid (Marplan), tranylcypromine (Parnate), phenelzine (Nardil), selegiline (Eldepryl, Emsam),... 

Toth et al. Commonly used muscle relaxant therapies for acute low back pain a review of carisoprodol, cyclobenzaprine hydrochloride, and metaxalone. Clin Iher 2004 26(9) 1355-1367. 

Cyclobenzaprine is a central-acting muscle relaxant that is commonly used to treat pain from injury, muscle spasms, and other painful musculoskeletal conditions. It is structurally related to first-generation tricyclic antidepressants such as imipramine and amitriptyline and appears to inhibit the uptake of norepinephrine in the locus coeruleus. Tricyclic compounds with norepinephrine reuptake-inhibiting properties have been shown to exert analgesic effects in chronic nerve and muscle pain by acting primarily within the central nervous system at brainstem as opposed to spinal cord levels, although their action on the latter may contribute to their overall skeletal muscle relaxant activity. The exact mechanism of action of cyclobenzaprine is unknown. 

Muscle relaxants such as cyclobenzaprine should be considered for the multimodal management of acute... 

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