Neurology and Pharmacology

• The neurological system is reviewed, and pharmacology for muscle spasms, seizure disorders, Parkinson's, Alzheimer's, and migraine headaches are covered.

Review of Systems

• The central nervous system comprises the brain and spinal cord.
• The peripheral nervous system includes spinal nerves, cranial nerves, and the autonomic nervous system, which is further divided into the sympathetic and parasympathetic systems.

Drugs for Muscle Spasms

• Centrally acting muscle relaxants treat spasms related to spinal cord injury, multiple sclerosis, cerebral palsy, spasms due to injury, and acute disorders.
• Peripherally acting muscle relaxants treat muscle spasms related to CVA or stroke, and malignant hyperthermia.

Dantrolene

• Dantrolene is a peripherally acting muscle relaxant.
• It inhibits the release of calcium, which is needed for normal muscle contraction, effectively blocking muscle contraction.
• Undesirable, unwanted effects from drugs are considered to be adverse drug reactions.
• Adverse drug reactions (ADR) for Dantrolene includes muscle weakness and drowsiness.
• Other ADRs include dizziness, diarrhea, and liver failure with prolonged use.
• Monitor for CNS issues such as dizziness and weakness.
• Assist with ambulation, and monitor for diarrhea and liver function.
• It can be administered PO or IV; IV use is indicated for malignant hyperthermia.
• Patients should avoid driving or other activities requiring alertness.
• Patient should avoid concurrent alcohol and CNS depressant use.
• Patient should report signs of liver damage.
• Signs of liver damage include abdominal pain, jaundice (in the skin and sclera of eyes; under the tongue for darker skin tones), and ascites.
• Contraindications/precautions includes liver disease and it should be used with caution.
• Interactions exists with CNS depressants, alcohol, and calcium channel blockers.
• It is important to remember that Dantrolene inhibits calcium release.

Baclofen

• Baclofen is a centrally acting muscle relaxant.
• It enhances the inhibitory effects of GABA on receptors, which suppresses hyperactive reflexes.
• The adverse drug reactions for Baclofen are similar to Dantrolene.
• Other adverse effects include nausea/vomiting, constipation/urinary retention.
• Baclofen should not be stopped abruptly.
• Interventions for Baclofen include starting with a low dose and increasing slowly.
• Baclofen should be taken with food to decrease gastric irritation.
• Encourage interventions for constipation
• Baclofen must be tapered over 1-2 weeks to prevent withdrawal symptoms.
• Withdrawal symptoms include seizures, and hallucinations.
• Administration considerations include starting with a low dose and preventing gastric upset.
• If oral administration does not work, use an intrathecal pump.
• Patients should be educated about drowsiness.
• It's important to change positions slowly and to prevent GI upset and constipation.
• Contraindications/precautions include use with other MAOIs and SSRIs.
• Avoid alcohol and other CNS depressants during use, as it increases sedation.

Anticonvulsants

• Traditional anticonvulsants include phenytoin (Dilantin) and carbamazepine (Tegretol).
• Valproic Acid (Depakote, Depacon, DEPA) is also used, as well as newer medications.
• Anticonvulsants delay an influx of sodium ions across the neuronal membrane.
• Sodium movement is the factor that determines whether a neuron will undergo an action potential.
• Sodium channels are desensitized but not blocked.
• Anticonvulsants provide effective seizure suppression, without the abuse potential or CNS depression associated with barbiturates.
• Dosage must be individualized because the ability to metabolize phenytoin-related drugs varies greatly.

Phenytoin (Dilantin)

• The mechanism of action is to desensitize sodium channels.
• It treats all types of epilepsy except absence seizures.
• Adverse effects of include CNS depression, gingival hyperplasia, skin rash, cardiac dysrhythmias, and hypotension.
• Hydantoin and phenytoin-like drugs require monitoring of serum drug levels.
• Monitor for signs of toxicity, blood dyscrasias and bleeding disorders, liver and kidney function.
• Fatal hepatotoxicity can occur.
• Contraindications include hypersensitivity to hydantoin products.
• Use cautiously with rash, seizures due to hypoglycemia, sinus bradycardia, and heart conditions.
• Serum Phenytoin level should be monitored; therapeutic level is between 10-20 ug/ml. Sub therapeutic level is <10 ug/ml, toxic level is >20 ug/ml.
• Anti-seizure medications should be tapered gradually over several months.
• It is important to resume medications if seizures return.
• Patient must also be aware of rebound seizures.

If anticonvulsants don't work

• Benzodiazepines such as Diazepam (Valium) can be administered.
• The mechanism of action is similar to that of barbiturates but safer.
• Primary use is for short-term seizure control.
• Adverse effects consist of drowsiness and dizziness, and hypotension.
• The client needs to be monitored for drug-abuse potential.
• Administration concerns includes respiratory depression may result with other CNS depressants.
• Overdose is treated with flumazenil (Romazicon).
• Monitor the airway and respirations due to the CNS depressant effects.

Jeopardy Review

• $200 - Expected Pharm Action for Phenytoin
• $400 - Adverse Drug Reactions for Phenytoin
• $600 - Nursing Actions or Interventions for Phenytoin
• $800 - Administration and Client Education for Phenytoin
• $1000 - Contraindications and Precautions and Interactions for Phenytoin
• $200 - Expected Pharm Action for Carbamazepine
• $400 - Adverse Drug Reactions for Carbamazepine
• $600 - Nursing Actions and Interventions for Carbamazepine
• $800 - Administration and Client Education for Carbamazepine
• $1000 - Contraindications and Precautions and Interactions for Carbamazepine
• $200 - Expected Pharm Action for Valproic Acid
• $400 - Adverse Drug Reactions for Valproic Acid
• $600 - Nursing Actions and Interventions for Valproic Acid
• $800 - Administration and Client Education for Valproic Acid
• $1000 - Contraindications and Interactions and Precautions for Valproic Acid
• $200 - What Route is the Quickest for Absorption?
• $400 - What Factors Would Affect Distribution?
• $600 - What Labs Would you Look at to Assess Drug Metabolism?
• $800 - What Labs Would you Look at to Assess Excretion?
• $1000 - A Patient has Elevated Liver Function Tests. What are you Concerned About?
• $200 - Expected Action of Dantrolene
• $400 - Adverse Drug Reactions for Baclofen
• $600 - Nursing Actions and Interventions for Dantrolene
• $800 - Client Education Regarding Dantrolene
• $1000 - Contraindications Precautions or Interactions for Baclofen
• $200 - What is Half-Life?
• $400 - A Long Half-Life Means You Need to Dose Less/More Frequently?
• $600 - A Short Half-Life Means You Need to Dose Less/More Frequently?
• $800 - You Give a 1 mg Dose of Medication with a Half-Life of 6 Hours. Approx How Many mg Left After 6 Hours?
• $1000 - How Many Half-Lives Does it Take for a Medication to be Gone From the Body?