CHAPTER 25 Drugs for Muscle Spasm and Spasticity

Muscle spasm is defined as

involuntary contraction of a muscle or muscle group. Muscle spasm is often painful and reduces the ability to function.

Dantrolene route

oral

DRUGS USED TO TREAT MUSCLE SPASM: CENTRALLY ACTING SKELETAL MUSCLE RELAXANTS

Baclofen. Carisoprodol. Chlorzoxazone. Cyclobenzaprine. Diazepam. Metaxalone. Methocarbamol. Orphenadrine. Tizanidine.

intrathecal baclofen

Abrupt discontinuation of intrathecal baclofen can lead to rhabdomyolysis, multiple organ system failure, and death.

Oral

All central skeletal muscle relaxants. Parenteral. Methocarbamol and diazepam may be given IM and IV as well as PO. Lehne, Richard A.; Rosenthal, Laura (2014-06-25). Pharmacology for Nursing Care (Page 255). Elsevier Health Sciences. Kindle Edition.

key point

All centrally acting muscle relaxants produce generalized CNS depression.

BACLOFEN Baseline Data

Assess for spasm, rigidity, pain, range of motion, and dexterity. Obtain baseline LFTs.

Dantrolene Baseline Data

Assess for spasm, rigidity, pain, range of motion, and dexterity. Obtain baseline LFTs.

Identifying High-Risk Patients

Avoid chlorzoxazone, metaxalone, and tizanidine in patients with liver disease.

The nurse is presenting an inservice program about baclofen and explains that it is indicated for the treatment of what? (Select all that apply.)

Baclofen acts within the spinal cord to suppress hyperactive reflexes involved in the regulation of muscle movement. Baclofen can reduce spasticity associated with multiple sclerosis, spinal cord injury, and cerebral palsy but not that associated with stroke. It does not relieve the spasticity of Parkinson's disease or Huntington's chorea.

Baclofen and diazepam

Baclofen and diazepam relieve spasticity by mimicking the inhibitory actions of GABA in the CNS.

The nurse correlates the mechanism of action of diazepam with enhanced effects of what

Diazepam enhances the effects of gamma-aminobutyric acid (GABA), which is an inhibitory transmitter

Chlorzoxazone,

Chlorzoxazone, a central muscle relaxant, is marginally effective and can cause fatal hepatic necrosis. Accordingly, the drug should be avoided.

The nurse recognizes that ________, used for spasticity, works by direct action on skeletal muscle.

Dantrolene works directly on skeletal muscle by suppressing the release of calcium from the sarcoplasm reticulum. This decreases muscle contraction. Baclofen and diazepam work within the central nervous system to treat spasticity.

The nurse recognizes that drugs for spasticity are indicated for patients with which condition?

Drugs for spasticity are used in the treatment of multiple sclerosis, cerebral palsy, and traumatic spinal cord injury

Baseline Data

For patients taking metaxalone and tizanidine, obtain baseline LFTs.

dantrolene

In addition to relief of spasticity, dantrolene is used to treat malignant hyperthermia, a potentially fatal condition caused by succinylcholine and general anesthetics.

dantrolene

In contrast to all other drugs discussed in this chapter, dantrolene acts directly on muscle to promote relaxation.

centrally acting muscle relaxants

Like the centrally acting muscle relaxants, baclofen and diazepam cause generalized CNS depression.

Before the administration of metaxalone, it is most important for the nurse to assess what?

Liver function should be routinely assessed in the patient receiving metaxalone because it can cause liver damage. If liver damage results, the drug should be discontinued.

Localized muscle spasm

Localized muscle spasm is treated with centrally acting muscle relaxants and aspirin-like drugs.

Dantrolene adverse effects

Monitor LFTs and assess for reduced muscle strength.

The nurse looks for muscle spasm in the patient with which condition

Muscle spasm is defined as involuntary contraction of a muscle or muscle group. Muscle spasm is often painful and decreases the patient's level of functioning. Spasm can result from a variety of causes, including epilepsy, hypocalcemia, acute and chronic pain syndromes, and trauma (localized skeletal muscle injury).

BACLOFEN routes

Oral, intrathecal.

The nurse observes the patient with suspected baclofen overdose for what complication?

Overdose of baclofen can cause respiratory depression and coma. In the case of abrupt discontinuation of this drug, the patient may experience visual hallucinations, paranoid ideations, and seizures. Baclofen should not be abruptly discontinued but withdrawn over 1 to 2 weeks.

BACLOFEN Administration

Patients with muscle spasm may be unable to self-medicate. Provide assistance if needed.

Dantrolene administration

Patients with muscle spasm may be unable to self-medicate. Provide assistance if needed.

Therapeutic Goal

Relief of signs and symptoms of muscle spasm.

BACLOFEN

Relief of signs and symptoms of spasticity.

Dantrolene Therapeutic goal

Relief of signs and symptoms of spasticity.

Muscle spasm

Spasm can result from a variety of causes, including epilepsy, hypocalcemia, acute and chronic pain syndromes, and trauma. Discussion here is limited to spasm resulting from muscle injury.

Spasticity is treated

Spasticity is treated with three drugs: baclofen, diazepam, and dantrolene.

Dantrolene mechanism of action

The heat of malignant hyperthermia is generated by muscle contraction occurring secondary to massive release of calcium from the sarcoplasmic reticulum. Dantrolene relieves symptoms of malignant hyperthermia by acting on the sarcoplasmic reticulum to block the release of calcium.

dantrolene

With prolonged use, dantrolene can cause potentially fatal liver damage. Monitor liver function and minimize dosage and duration of treatment.

Which central muscle relaxant is effective in the treatment of spasticity associated with central nervous system pathology?

With the exception of diazepam, the central muscle relaxants are not useful for treating spasticity of other muscle disorders caused by central nervous system pathology.