Chapter 25: Muscle Relaxants

baclofen indication

Alleviation of signs and symptoms of spasticity; use in spinal cord injuries or diseases

Centrally Acting Skeletal Muscle Relaxants Drug

Baclofen

Dantrolene adverse effects

Fatigue, weakness Drowsiness, dizziness, confusion Myalgia GI irritation, diarrhea, Enuresis, urinary frequency Hepatitis Tachycardia, transient blood pressure changes Rash

Baclofen drug interactions

CNS depressants Alcohol

Dantrolene indications

Control of clinical spasticity resulting from upper motor neurons disorders Preoperatively to prevent or attenuate the development of malignant hypothermia Management of spasticity associated with neuromuscular diseases: Spinal cord injury, cerebral palsy, myasthenia gravis, multiple sclerosis, muscular dystrophy, tetanus, polio, quadriplegia, amyotrophic lateral sclerosis

Pyramidal Tract

Controls precise intentional movements

Direct-Acting Skeletal Muscle Relaxants Drugs

Dantrolene

Implementation for Dantrolene

Discontinue drug at any sign of liver dysfunction e.g. nausea, fatigue, anorexia Monitor IV site for extravasation, drug is alkaline and irritating to tissue Institute other comfort measures and therapeutic goals

Baclofen adverse effects

Drowsiness, Dizziness Fatigue Weakness Headache Nausea Dry mouth Hypotension Constipation Urinary frequency

Patient Teaching for Dantrolene

Drug name. dosage, measures for avoidance of adverse effects, warning signs of possible problems Offer support and encouragement

patient teaching for Baclofen

Drug name. dosage, measures for avoidance of adverse effects, warning signs of possible problems Offer support and encouragement If Patient is receiving baclofen through a delivery pump, teach about the pump (dose adjustment and programing unit), reason for frequent monitoring Provide additional measures to relieve discomfort: •Heat, rest for muscle, NSAIDs, positioning

Dantrolene Drug-Drug Interactions

Estrogen Neuromuscular junction blockers and others that interfere with neuromuscular transmission

Nursing Considerations for Direct-Acting Skeletal Muscle Relaxants Assess for Dantrolene

History and Physical Exam Known allergies CNS orientation, affect, reflexes, bilateral grip strength, and spasticity Respiration and adventitious sounds; pulse, electrocardiogram, and cardiac output; bowel sounds and reported output; and liver and renal function tests

Nursing Considerations for Centrally-Acting Skeletal Muscle Relaxants Assess

History and Physical Exam Known allergy, cardiac depression, epilepsy, muscle weakness, or rheumatic disorder CNS orientation, affect, reflexes, bilateral grip strength, and spasticity, evaluation; bowel sounds and reported output; and liver and renal function tests Assess baseline status before beginning therapy and for any potential adverse affects

Dantrolene action

Interfering with the release of Calcium from the muscle tubules This prevent the fibers from contracting

Simple (spinal) reflexes

Involving an incoming sensory neuron and an outgoing motor neuron

complex spinal reflex

Involving interneurons which communicate with the related centers in the brain

Baclofen contraindications

Known allergy Rheumatic disorders Pregnancy and lactation Epilepsy Cardiac dysfunction Conditions marked by muscle weakness

Dantrolene contraindications

Known allergy Spasticity- that contributes to locomotion, upright position, or increased function Hepatic disease Lactation Cautions Women Pregnancy or lactating All patients older than 35 years Cardiac disease

Extrapyramidal Tract

Modulates unconsciously controlled muscle activity Allows the body to make automatic adjustments in posture, position, and balance

Implementation for Baclofen

Monitor respiratory status to evaluate for adverse effects and arrange for dosage adjustment or discontinuance of drug; Monitor patient response for improvement in muscle spasm and relief of pain

Muscle Spasm

Often results from injury to the musculoskeletal system Caused by the flood of sensory impulses coming to the spinal cord from the injured area

Nerves and Movement

Posture, balance, and movement are the result of a constantly fluctuating sequence of muscle contraction and relaxation. The nerves that regulate these actions are the spinal motor neurons. Spinal Reflexes: simplest nerve pathways that monitor movement and posture Influences from Upper-level CNS Areas Basal ganglia Cerebellum Cerebral cortex

Baclofen Pharmacokinetics

Rapidly absorbed and metabolized in the liver Excreted in the urine Oral or intrathecal

Muscle Spasticity

Result of damage to neurons within the CNS May result from an increase in excitatory influences or a decrease in inhibitory influences within the CNS

Dantrolene Pharmacokinetics

Slowly absorbed from the GI tract Metabolized in the liver T ½ 4-8 hours oExcreted in the urine

Baclofen Action

Work in upper levels of CNS to interfere with reflexes causing muscle spasm Possible depression anticipated with their use Lyse or destroy spasm (spasmolytics) Exact mechanism unknown, thought to involve action in upper or spinal interneurons