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