CNS Drugs & Seizures

• Central Nervous System (CNS) drugs treat neurological disorders like epilepsy, muscle spasms, Parkinson's Disease (PD), and migraines.
• These drugs affect the brain and spinal cord, influencing neurotransmitter levels and neural activity.

Medications for Epilepsy/Seizures

• Epilepsy involves recurring seizures due to abnormal neuronal activity, and treatment aims to reduce seizure frequency and severity.

Types of Seizures

• Partial/Focal Seizures

  • Simple Partial seizures do not cause loss of consciousness, but do cause motor/sensory symptoms.
  • Complex Partial seizures cause altered consciousness, preceded by an aura, and followed by a postictal period.
  • Secondarily Generalized seizures start as partial seizures, and develop into generalized tonic-clonic seizures.

• Generalized Seizures

  • Absence (Petit Mal) seizures are brief, cause unresponsiveness, and have no postictal period.
  • Tonic-Clonic (Grand Mal) seizures cause major convulsions and postictal confusion.
  • Myoclonic seizures cause sudden muscle contractions.
  • Atonic seizures cause loss of muscle tone, known as "drop attacks".

Anticonvulsant Drugs

• Carbamazepine (Tegretol)

  • Treats partial, generalized tonic-clonic, and complex partial seizures, as well as bipolar disorder.
  • Adverse effects include diplopia, blurred vision, N/V, and leukopenia.
  • Administer as a shaken oral suspension, monitor CBC, and avoid ETOH and grapefruit.

• Valproic Acid (Depakote)

  • Treats absence, myoclonic, tonic-clonic, and partial seizures, migraines, and bipolar disorder.
  • Therapeutic levels range from 50-100 mcg/ml.
  • Adverse effects include N/V, lethargy, liver toxicity, and is pregnancy category X.

• Gabapentin (Neurontin)

  • Used as an adjuvant for partial seizures and neuropathic pain.
  • Adverse effects include fatigue, dizziness, ataxia, and leukopenia.

• Lamotrigine (Lamictal)

  • Used as adjuvant therapy and to treat bipolar disorder.
  • Adverse effects include dizziness, rash, and Stevens-Johnson syndrome.

• Topiramate (Topamax)

  • Treats partial and generalized seizures, prevents migraines, and aids with weight loss.
  • Adverse effects include drowsiness, dizziness, and cognitive effects.

Safety and Monitoring

• Consistent drug dosing is critical for safety and efficiency
• Plasma drug levels should be monitored consistently
• A seizure frequency chart should be maintained
• It is important to monitor serum levels for therapeutic range and safety

Muscle Spasm and Spasticity

• Muscle spasms are involuntary contractions that causes pain, while spasticity involves increased muscle tone and stiffness; often due to neurological conditions.

Centrally Acting Muscle Relaxants

• Carisoprodol, Cyclobenzaprine, Methocarbamol, and Tizanidine are centrally acting muscle relaxants.
• Adverse effects include CNS depression, drowsiness, dizziness, and hypotension.
• These drugs are effective in 30-60 minutes, for short-term use (2-3 weeks), and interact with CNS depressants and MAO inhibitors.

Specific Drugs for Spasticity

• Baclofen (Lioresal)

  • Treats spasticity due to multiple sclerosis and spinal cord injury.
  • Withdrawal symptoms can occur and should be tapered off gradually.

• Diazepam (Valium)

  • Treats spasticity, acts on GABA receptors, and causes sedation.

• Dantrolene (Dantrium)

  • Acts directly on skeletal muscle, and treats malignant hyperthermia.
  • Adverse effects include muscle weakness, drowsiness, and liver toxicity.

Medications for Parkinson's Disease

• Parkinson's Disease (PD) is a progressive disorder that causes tremors, stiffness, and bradykinesia due to dopamine deficiency.

Drug Classes

• Dopamine Replacement

  • Levodopa/Carbidopa (Sinemet)
    • Enhances dopamine levels and reduces peripheral adverse effects.

• Dopamine Agonists

  • Pramipexole (Mirapex)
    • Used in early PD and with levodopa in advanced PD, with fewer dyskinesias compared to levodopa.

• COMT Inhibitors

  • Entacapone (Comtan)
    • Inhibits levodopa breakdown, prolongs its availability, and must be tapered off gradually.

Anti-Migraine Medications

• Migraines involve severe headaches often accompanied by sensory disturbances.

Triptans

• Serotonin agonists cause blood vessel constriction, reducing inflammation.
• Can be administered via oral, nasal spray, or subcutaneous injection.
• Adverse effects include dizziness, nausea, serious effects like heart attack and stroke.
• Contraindications include heart disease history, hypertension, and liver disease.

Phenytoin (Dilantin)

• Treats all major forms of epilepsy except absence seizures.

Adverse Effects

• CNS Toxicity: Nystagmus, ataxia, decreased level of consciousness occur at high blood levels.
• Other Effects: Gingival hyperplasia, skin reactions including Stevens-Johnson syndrome, teratogenic effects, CV effects like hypotension and dysrhythmias can occur.

Additional Notes

• These are some addition things to keep in mind in relation to CNS drugs

Drug Interactions

• Levodopa absorption and effectiveness can be reduced by protein intake.
• Non-selective MAO inhibitors and antipsychotic agents can interact adversely with levodopa.
• Anticholinergic drugs and OTC preparations can interact with CNS drugs, leading to increased side effects.

Nursing Implications

• Consistent drug dosing is important.
• Improvements in daily activities and symptom reduction should be assessed.
• Patients should know that there is a potential for abrupt loss of therapeutic effects.
• High-protein intake should be avoided when taking drugs like levodopa/carbidopa.