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Ppt chapter 20
- 1. Chapter 20
Drugs Affecting Muscle Spasm
and Spasticity
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 2. Physiology
• The human body contains approximately 600 skeletal
muscles.
• Skeletal muscle movement is voluntary.
• Striated muscle is composed of two contractile proteins.
• Muscle contraction is triggered by a sudden inflow of
calcium ions (Ca2+).
• In the resting state, the protein tropomyosin winds
around actin and covers the myosin-binding sites.
• Muscle contraction stops when Ca2+ is removed from the
immediate environment of the myofilaments.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 4. Pathophysiology
• Muscle spasm
– A muscle spasm is a sudden, violent involuntary
contraction of a muscle or group of muscles.
– Spasms are related to a localized skeletal muscle
injury or an imbalance in electrolytes.
– Tonic spasm is characterized by an unusually
prolonged and strong muscular contraction.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 5. Pathophysiology (cont.)
• Spasticity
– Spasticity is a condition in which certain muscles are
continuously contracted.
– This contraction causes stiffness or tightness of the
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
muscles.
– Spasticity may be associated with spinal cord injury.
- 6. Centrally Acting Muscle Relaxants
• They act in the central nervous system (CNS).
• Prototype drug: cyclobenzaprine (Flexeril)
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 7. Cyclobenzaprine: Core Drug Knowledge
• Pharmacotherapeutics
– Manages muscle spasms associated with acute
musculoskeletal disorders
• Pharmacokinetics
– Administered: oral. Metabolism: liver. Excreted:
urine and bile. Onset: 1 hour. Duration: 12 to 24
hours.
• Pharmacodynamics
– Relieves muscle spasms through a central action
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 8. Cyclobenzaprine: Core Drug Knowledge
(cont.)
• Contraindications and precautions
– Hyperthyroidism
– 14 days within use of MAOIs
• Adverse effects
– CNS depression and anticholinergic activity
– Arrhythmias, seizures, and MIs
• Drug interactions
– Tramadol, guanethidine, MAOIs, histamine-1
blocking agents, and various herbal remedies
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 9. Cyclobenzaprine: Core Patient Variables
• Health status
– Assess past medical history and drug allergies.
• Life span and gender
– Pregnancy Category B drug
– Use precaution in administration to the elderly.
• Lifestyle, diet, and habits
– Avoid alcohol and other CNS depressant use.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
• Environment
– Assess the environment where the drug will be given.
- 10. Cyclobenzaprine: Nursing Diagnoses and
Outcomes
• Risk for Injury related to CNS depressant effects and
potential cardiovascular effects.
– Desired outcome: The patient will remain free from
injury throughout therapy.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 11. Cyclobenzaprine: Planning and
Interventions
• Maximizing therapeutic effects
– Take with full glass of water at evenly spaced
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
intervals.
– Coordinate physical therapies with administration.
• Minimizing adverse effects
– Assess for excessive sedation.
– Caution the patient about the potential for orthostatic
hypotension.
- 12. Cyclobenzaprine: Teaching, Assessment,
and Evaluation
• Patient and family education
– Take medication as prescribed.
– Explain adverse effects.
– Do not take with other OTC medications.
• Ongoing assessment and evaluation
– Evaluate the patient’s safety.
– Monitor the level of sedation.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 13. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
• Cyclobenzaprine is chemically similar to which of the
following drugs?
– A. Adrenergic agents
– B. Benzodiazepines
– C. Tricyclic antidepressants
– D. MAOIs
- 14. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
• C. Tricyclic antidepressants
• Rationale: Cyclobenzaprine is structurally similar to
the tricyclic antidepressants.
- 15. Centrally Acting Spasmolytics
• The centrally acting spasmolytics work in the CNS to
reduce excessive reflex activity.
• Allow muscle relaxation
• Prototype drug: baclofen (Lioresal)
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 16. Baclofen: Core Drug Knowledge
• Pharmacotherapeutics
– Relieves some components of spinal spasticity
• Pharmacokinetics
– Administered: oral. Distribution: crosses blood–brain
barrier. Metabolism: liver. Excreted: urine and bile.
Peaks: 2 to 3 hours
• Pharmacodynamics
– Acts specifically at the spinal end of the upper motor
neurons at GABAB receptors to cause
hyperpolarization
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 17. Baclofen: Core Drug Knowledge (cont.)
• Contraindications and precautions
– Hypersensitivity and spasticity of cerebral origin
• Adverse effects
– Drowsiness, weakness, dizziness and light-headedness,
headache, nausea and vomiting,
hypotension, constipation, lethargy and fatigue,
confusion, insomnia, and increased urinary frequency
• Drug interactions
– CNS depressants or TCAs
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 18. Baclofen: Core Patient Variables
• Health status
– Assess past medical history and allergies.
– Perform physical assessment.
• Life span and gender
– Older patients are more susceptible to sedation.
• Lifestyle, diet, and habits
– Caution the patient about the concurrent use of
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
alcohol.
• Environment
– Assess the environment where the drug will be given.
It is usually given at the home.
- 19. Baclofen: Nursing Diagnoses and
Outcomes
• Acute Pain related to headache, muscle pain, GI
disturbances, or rash
– Desired outcome: The patient will be provided with
measures to decrease the discomfort of drug therapy
and the possibility of nonadherence.
• Risk for Disturbed Sensory Perception related to visual
changes, vestibular dysfunction, and somatosensory
changes
– Desired outcome: The patient will be protected
from injury if dizziness, weakness, visual changes, or
perceptual changes occur.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 20. Baclofen: Planning and Interventions
• Maximizing therapeutic effects
– Take with full glass of water at evenly spaced
intervals.
– If GI distress occurs, coordinate with meals.
• Minimizing adverse effects
– Ensure patient safety.
– Do not abruptly stop the medication.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 21. Baclofen: Teaching, Assessment, and
Evaluation
• Patient and family education
– Teach the importance of patient safety.
– Caution the patient about the concurrent use of
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
alcohol.
• Ongoing assessment and evaluation
– Monitor for the emergence of hallucinations or
psychotic episodes.
– Assess for improved symptoms of spasticity.
- 22. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
• Baclofen therapy is effective at treating muscle spasms
due to a cerebral vascular accident.
– A. True
– B. False
- 23. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
• B. False
• Rationale: Baclofen therapy does not affect skeletal
muscle spasms resulting from CVA or parkinsonism.
Baclofen does not treat this condition because of the
mechanism of action of the drug.
- 24. Peripherally Acting Spasmolytics
• Peripherally acting spasmolytics relax muscles through
direct action on the skeletal muscle fibers.
• They do not interfere with neuromuscular
communication.
• They have no CNS effects.
• Prototype drug: dantrolene (Dantrium)
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 25. Dantrolene: Core Drug Knowledge
• Pharmacotherapeutics
– Used to treat malignant hyperthermia
• Pharmacokinetics
– Administered: oral or IV. Metabolism: liver. Excreted:
kidneys. Peak: 5 hours. T½: 7.3 hours
• Pharmacodynamics
– Reduces the amount of Ca2+ released from the
sarcoplasmic reticulum, thereby relaxing the muscle
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 26. Dantrolene: Core Drug Knowledge (cont.)
• Contraindications and precautions
– Liver disease
• Adverse effects
– Muscle weakness, fatal hepatitis, seizures, and pleural
effusion with pericarditis
• Drug interactions
– CNS depressants, clofibrate, estrogens, verapamil,
and warfarin
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 27. Dantrolene: Core Patient Variables
• Health status
– Assess past medical and physical assessment.
• Life span and gender
– Consider the age before administration.
• Lifestyle, diet, and habits
– Assess for lactose intolerance.
• Environment
– Can cause photosensitivity
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 28. Dantrolene: Nursing Diagnoses and
Outcomes
• Risk for Injury related to muscular weakness
– Desired outcome: The patient will be injury free
despite muscular weakness.
• Risk for diarrhea or constipation related to drug effects
– Desired outcome: The patient will maintain
baseline bowel habits.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 29. Dantrolene: Nursing Diagnoses and
Outcomes (cont.)
• Risk for Disturbed Sensory Perception: Kinesthetic
related to dizziness, malaise, and fatigue
– Desired outcome: The patient will remain free of
injury from adverse effects.
• Disturbed Body Image related to drug-related
dermatologic effects
– Desired outcome: Any adverse effects will be
resolved by the end of therapy.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 30. Dantrolene: Planning and Interventions
• Maximizing therapeutic effects
– Administer with food or milk to avoid gastric distress.
– Do not crush extended release capsules.
• Minimizing adverse effects
– Provide for patient safety.
– Advise the use of sunscreen.
– Titrate dose to maximum effectiveness.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 31. Dantrolene: Teaching, Assessment, and
Evaluation
• Patient and family education
– Explain why the drug is prescribed.
– Discuss adverse effects of the drug.
• Ongoing assessment and evaluation
– Monitor for improvement in symptoms of spasticity
and decrease in resistance to passive movement.
– Monitor for adverse effects.
Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
- 32. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Question
• Dantrolene is used to treat which of the following
condition(s)?
– A. Hypertensive crisis
– B. Malignant hyperthermia
– C. Pain associated with lumbar stenosis
– D. All of the above
- 33. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins
Answer
• B. Malignant hyperthermia
• Rationale: IV dantrolene is the drug of choice for
acute treatment of malignant hyperthermia.
Preoperatively, it can be used orally or intravenously
to prevent malignant hyperthermia in patients
considered at risk.