Nervous System: Medications and Key Terms

Nervous System Introduction

• Chapter 13 focuses on nervous system medications
• There are two major branches of the nervous system; the central and peripheral
• Nervous system medications can treat behavioral, emotional, or mood disorders
• Anxiolytics act on the CNS & PNS, and control communication

Key Terms

• Adrenergic (Sympathomimetics) Mimic the sympathetic nervous system which is involved in the fight-or-flight response
• Analgesics are medications used for pain relief
• Anxiolytics medications are employed to alleviates anxiety
• Aura is a sensory perception that someone experiences before seizures or migraines
• Autonomic Nervous System controls involuntary bodily functions
• Blood-brain barrier is a protective mechanism that restricts the passage of certain substances from the bloodstream into the brain
• Central Nervous System (CNS) comprises the brain and spinal cord
• Cholinergic (Parasympathomimetic) mimics the parasympathetic nervous system responsible for the "rest and digest" functions
• Drug holiday is a planned break from taking a medication to reduce tolerance or side effects
• Gamma-aminobutyric acid (GABA) is a neurotransmitter that inhibits nerve impulses
• Hydantoins is a class of anti-seizure medications
• Monoamine oxidase inhibitors (MAOIs) are a class of antidepressants
• Narcotics are drugs used to relieve pain and can cause drowsiness and altered mental state
• Neuroleptic refers to a medication used to treat psychosis
• Neurotransmitters are chemical messengers that transmit signals between nerve cells
• Parasympathetic Nervous System (PNS) controls bodily functions when a person is at rest
• Peripheral Nervous System (PNS) includes all the nerves outside the brain and spinal cord
• Psychotropic medications affect the mind or behavior
• Selective Serotonin Reuptake Inhibitors (SSRIs) are a class of antidepressants that increase serotonin levels in the brain
• Somatic Nervous System controls voluntary movements of the body
• Status Epilepticus is a state of continuous seizure activity or rapidly repeating seizures
• Sympathetic Nervous System responsible for the "fight or flight" response
• Synapse the junction between two nerve cells where nerve impulses are transmitted

Overview of The Nervous System

• Subdivided into the CNS and PNS
• The CNS includes the brain and spinal cord
• The PNS includes the somatic and autonomic nervous systems
• Somatic is voluntary
• Autonomic is involuntary

Classes of Medications

• The five categories of nervous system medications:
• Medications to treat pain and fever
• Medications to treat anxiety, insomnia, sedation and seizures
• Medications to treat behavioral, emotional and mood disorders
• Medications to treat psychosis
• Medications to treat dementia, and Parkinson's disease
• Nervous system medications often cross the blood-brain barrier and this can cause serious side effects
• Medications influence pain, anxiety, depression, mania, insomnia, convulsions, and schizophrenia

Peripheral Nervous System in Detail

• Somatic Nervous system: Voluntary control of muscles
• The Autonomic nervous system: Involuntary control of internal organs
• The sympathetic controls the fight or flight response
• The parasympathetic helps with body rest and relaxation
• Cholinergic nerve cells release acetylcholine which helps relax the body
• Adrenergic release epinephrine or norepinephrine which excite the body
• If the needs can not be meet equivalencies through medication can be used

Sympathomimetics

• Mimic the sympathetic nervous system when the body needs to be excited
• Stimulates fight or flight
• Restores heart rhythm, increases blood pressure, constricts capillaries and/or dilates pupils for eye procedures
• Used with caution if hypertension is over 160, myocardial infarction, atrial fibrillation, hypovolemia, children, pregnancy and breastfeeding
• Examples include Levophed and epinephrine

Adrenergic Blockers

• Blocks the action of adrenergics resulting in a parasympathetic effect (calming)
• Calms lowering heart rate and relaxing blood vessels
• Treats cardiac arrhythmia, high blood pressure, migraine headaches, and chest pain
• Broken down into alpha (affects vascular smooth muscle: treat hypertension and BPH) and beta blockers (block epinephrine, slow heart rate and force: treat hypertension, migraines, glaucoma

Parasympathomimetics

• Mimic the parasympathetic system
• Release acetylcholine to relax fight or flight mechanism
• Rarely used due to severe decrease in heart rate, constriction of respiratory passages
• Nerve gas
• Pilocarpine treats open-angle glaucoma

Anticholinergics

• Example is Benadryl
• Inhibit the parasympathetic nervous system, and promote fight or flight
• Causes dry secretions
• Treats asthma, motion sickness, preoperative relaxation, neuromuscular blocking of spasms, antidotes for insect stings, cholinergic crisis
• Example includes Atropine

Analgesics

• Reduces pain without eliminating feeling or sensation
• Choices include aspirin, acetaminophen, nonsteroid inflammatory drugs and narcotics
• Aspirin coats platelets to make them slippery, causes GI distress, and can not be used in children
• Methylsalicylate are topical anti-inflammatory that irritates the skin to increase blood flow decreasing pain

Acetaminophen

• Decreases pain and fever without anti-inflammatory properties
• Found in cold medications
• Combined with narcotics like oxycodone to treat moderate to severe pain

Nonsteroidal Anti-inflammatory Drugs

• Reduces pain, inflammation, and fever
• Ibuprofen includes Advil and Motrin
• Can be combined with narcotics to relieve moderate to severe pain, like Oxycodone with ibuprofen
• Pain scale of 1-3 is mild, 4-6 is moderate, and 7-10 is severe

Opioid Analgesics

• Strong pain killers and suppresses the central nervous system
• Active ingredient in most narcotics is opium
• Excess use decreased blood pressure (risk of falls or death) and respirations
• Examples include Morphine, Codeine, Fentanyl
• Potential for addiction due to euphoria and severe side effects of slowed respirations and decreased blood pressure

Anxiety, Insomnia, Seizures Medications

• Limbic system of the brain is integral to emotions, memory and alertness
• When structures do not operate optimally this can result in; anxiety, sleeplessness, alertness or seizures

Anxiolytic Medications

• Reduces intensity of fears, dangers and tension which results in a calming effect
• CNS depressants treat anxiety and restlessness
• Benzodiazepines treat anxiety, seizures, alcohol withdrawal and muscle relaxation
• Lorazepam (Ativan), Diazepam (Valium), Alprazolam (Xanax)
• Barbiturates example is Phenobarbitol
• SSRI's: (Citalopram) Celexa, (Fluoxetine) Prozac, (Zoloft) Sertraline
• SNRI's: Venlafaxine (Effexor XR)
• Tricyclic antidepressants: Amitriptyline (Elavil) has fewer dependence issues

Insomnia

• Barbiturates induce sleep by depressing CNS
• Non-narcotic benzodiazepine hypnotics; Zolpidem (Ambien), Eszopicolone (Lunesta) has fewer side effects but possible addiction

Anti-seizure Medications

• Hydantoins example is Phenytoin/Dilantin which delays sodium to calm cells, and is beneficial for tonic-clonic/grand mal/partial seizures
• Barbiturates examples is Phenobarbital/Luminal which treats tonic-clonic and febrile seizure
• Succinimides example includes Ethosuximide/Zarontin which delays calcium to relax nerve cells, and absence/petit mal seizures
• Gamma is like Vigabatrin inhibits neurotransmitters to decrease activity
• Lamictal, Gabitril, Topamax, and/or Tegretol reduce seizures to manage alcohol withdrawals by reducing anxiety

Behavioral Mood Disorders

• Behavioral and emotional disorders includes a variety of mental health diagnoses and difficulty with relationships
• Mood disorders can result in highs and lows of mood
• CNS Stimulants like Adderall/Ritalin treat ADD/ADHD
• An amphetamine like phentermine increases metabolism to treat obesity
• Modafinil and armodafinil helps treat narcolepsy

Antidepressants

• Neurotransmitters need preserving at the synapse to prevent mood from being depressed
• MAOI: includes Selegiline/Eldepryl which requires dietary exclusion of tyramine, RARELY prescribed
• Tricyclic like Elavil/Amitriptyline keeps norepinephrine, serotonin and is used if the patient has sedative side effects
• SSRI's like Celexa prevents serotonin from being used at the synapse
• SNRI's block the re-uptake of serotonin to elevate mood

Mood Stabilizers

• Stabilizes shifts with bipolar and schizophrenia
• Lithium is a common mood stabilizer.
• It has a small therapeutic range and if it's an issue, patients should avoid salt since lithium toxicity can be fatal
• Other drugs are lamotrigine and valproic acid

Antipsychotics

• Used for delusional thinking
• Thorazine, Clopine, Mellaril treats abnormal actions, behaviors, and psychosis
• Used for other symptoms like nausea, vomiting, dementia, agitation, and spasms

Dementia and Parkinson's

• Dementia is the irreversible decline in mental function caused by Alzheimer's
• Dementia can be helped by Aricept a cholinesterase inhibitor slows the progression
• Parkinson’s is a degenerative CNS disorder
• Neurons that produce dopamine die leading to disorganized muscles
• Dopamine and acetylcholine cause tremors, slow movement, balance problems
• Drugs focus on keeping dopamine and acetylcholine at the nerve synapse
• Patients need a combination and a "drug holiday" to help
• Dopaminergic, cholinergic

Anesthesia Types

• Local: Creates a lack of feeling without a loss of consciousness
• Creams, Aerosol spray, otic, and injectable solutions are local options
• Amides last longer and adverse effects/allergies are rare
• Esters have potential allergies
• General Creates loss of both feeling and consciousness,
• IV infusion: like Midazolam, propofol, or ketamine used for longer procedures
• Inhalation therapy: Desflurane, isoflurane, sevoflurane can depress respiratory and cardiovascular function

Alcohol

• Is a rare prescribed CNS depressant that increases confusion, peripheral vasodilation, heart rate, electrolyte imbalances, unsteady gait, and slurred speech
• Chronically damages the CNS and increases tremors, GI Issues, falls, breakouts, neural issues, and conjunctivitis
• Treatment includes Disulfiram, behavior modification, vitamin B injections, and dietary changes