Nervous System, Cholinergics and CNS

• Adrenergic pertains to nerve fibers releasing norepinephrine or epinephrine at synapses
• Analgesics are medications that alleviate pain
• The autonomic nervous system (ANS) is self-controlling and functions independently
• The ANS operates without conscious effort to maintain homeostasis
• The blood-brain barrier consists of densely packed cells allowing certain chemicals and nutrients to pass into the central nervous system while restricting others

Central Nervous System (CNS)

• The CNS comprises the brain and spinal cord and processes information for the body
• The CNS can be excited or depressed by medications

Cholinergics

• Cholinergics (parasympathomimetics) are agents that produce the effect of acetylcholine
• Acetylcholine is a neurotransmitter carrying messages from the brain to the body via nerve cells

Drug Holiday

• A drug holiday is when a patient stops medications temporarily to allow resuming them at lower doses while achieving desired benefits

Gamma-Aminobutyric Acid (GABA)

• GABA is a neurotransmitter that slows down brain activity by blocking specific signals in the CNS
• GABA produces a calming effect

Hydantoins

• Hydantoins slow synaptic transmission by blocking sodium channels
• Hydantoins inhibit neurons from firing, preventing repeated excitation of cells that result in seizures

Monoamine Oxidase Inhibitors (MAOIs)

• MAOIs prevent the breakdown of brain chemicals that improve mood
• MAOIs treat depression and mental health disorders
• MAOIs prevent the breakdown of serotonin, dopamine, and norepinephrine, increasing their availability in the brain

Narcotics

• Narcotics are strong painkillers usually made from opium
• Narcotics can be physically and psychologically addictive

Neuroleptics

• Neuroleptics are medications used to treat psychoses

Neurotransmitters

• Neurotransmitters are chemical messengers transmitting signals between nerve cells
• Neurotransmitters enable nerve cells to communicate and control bodily functions

Parasympathetic Nervous System

• The parasympathetic NS controls the body’s relaxation response
• The parasympathetic NS is also known as the "rest and digest" system
• The parasympathetic NS slows heart rate, dilates blood vessels, and decreases pupil size
• The parasympathetic NS increases digestion, relaxes muscles in the digestive tract, maintains metabolism, and helps maintain resting bronchial constriction

Peripheral Nervous System (PNS)

• The PNS is a network of nerves throughout the head, neck, and body
• The PNS carries messages to and from the CNS
• Consists of the somatic nervous system and the autonomic nervous system

Psychotropic Medications

• Psychotropic medications affect brain function, causing changes in mood, awareness, thoughts, feelings, or behavior
• Alcohol, caffeine, nicotine, marijuana, and certain pain medicines are examples of psychotropic substances

Selective Serotonin Reuptake Inhibitors (SSRIs)

• SSRIs are antidepressants that prevent serotonin reabsorption in the brain, increasing its availability
• SSRIs help regulate mood and improve brain function

Somatic Nervous System

• The somatic NS is a component of the PNS associated with the voluntary control of body movements via skeletal muscles
• The somatic NS is responsible for consciously influencing body functions, such as moving arms and legs

Status Epilepticus

• Status epilepticus is a medical emergency involving a seizure lasting more than five minutes or multiple seizures without regaining consciousness
• Status epilepticus involves continuous seizure activity without a pause

Sympathetic Nervous System

• The sympathetic NS is a branch of the autonomic NS preparing the body for fight or flight situations
• The sympathetic NS increases heart rate, blood pressure, breathing rate, and pupil size
• The sympathetic NS inhibits digestion and other non-essential functions
• The sympathetic NS helps the body respond to stress or danger

Synapse

• A synapse is the gap between nerve cells where communication occurs

The Nervous System: Somatic vs Autonomic

• Somatic controls muscles
• Autonomic controls inner organs and is involuntary
• Acetylcholine and norepinephrine are two main neurotransmitters that affect autonomic nervous system
• Autonomic further broken down into sympathetic (fight or flight) and parasympathetic (rest and relax)

Autonomic Nervous System Medications

• Sympathomimetics (adrenergic) stimulate the fight or flight response by:
  • Stimulating the heart
  • Increasing blood flow to skeletal muscles
  • Constricting peripheral blood vessels
  • Dilating bronchi for asthma
  • Dilating pupils for eye procedures
  • Restoring heart rhythm during cardiac arrest
  • Increasing BP with norepinephrine during shock
  • Constricting capillaries if a patient is bleeding
• Adrenergic blockers calm the nervous system
  • Useful in treating cardiac arrhythmias, high blood pressure, migraines, and chest pain
    • Slow heart rate
    • Relax blood vessels
    • Reduce workload on heart
• Alpha blockers (-sin) affect vascular smooth muscle and alleviate HTN and BPH
  • Examples: alfuzosin, doxazosin, prazosin, tamsulosin, terazosin
• Beta blockers (-lol) block effects of epinephrine
  • Slow heart rate and reduce BP with less force
  • Used for HTN, migraines, and glaucoma
  • Examples: acebutolol, atenolol, bisoprolol, metoprolol, nadolol, nebivolol, propranolol
• Parasympathomimetics (cholinergics) mimic action of PNS and release acetylcholine, promoting relaxation
  • Rarely used because they severely slow body system activity and constrict respiratory passages
  • Nerve gas is an example.
  • Pilocarpine treats open-angle glaucoma (must be stopped before surgery due to increased risk of intraoperative breathing problems)
• Anticholinergics/Cholinergic Blockers inhibit PNS and promote fight or flight symptoms
  • Dry secretions, treat asthma and motion sickness, and provide preoperative relaxation for neuromuscular blocking of spasms, and are antidotes to insect stings.
  • Cholinergic crisis is often seen in myasthenia gravis due to excess acetylcholine.
  • Emergency atropine can be used to treat slow heart rate, heart block, or bronchospasm.

Medications for Pain and Fever

• Analgesics reduce pain without eliminating feeling or sensation
• Salicylates:
  • Aspirin (acetylsalicylic acid) relieves mild to moderate pain
    • Reduces inflammation/fever
    • Decreases inflammation in blood vessels
    • Improves cardiovascular flow
    • Can cause GI distress
    • Avoid in children due to Reye's syndrome risk
  • Methylsalicylate (Bengay) is a topical anti-inflammatory
    • Irritates the skin surface, increases blood flow, and decreases pain
• Acetaminophen decreases pain and fever without anti-inflammatory effects
  • Commonly combined with narcotics (oxycodone/Percocet) to treat moderate to severe pain
• Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce pain and swelling
  • Can reduce fever
  • Combined with narcotics oxy with ibuprofen (Combunox)
• Opioid analgesics are strong painkillers that suppress the CNS (main ingredient is opium)
  • Monitor for slowed respirations and decreased BP
  • Naloxone (Narcan) reverses opioid effects
  • Strongest: Morphine, meperidine (Demerol), and fentanyl

Medications for Anxiety, Insomnia, Sedation, and Seizures

• Limbic system integral to emotions, love, fear, anger, memory, and alertness
• Anxiolytic medications
  • Treat generalized anxiety disorder, panic disorder, PTSD, OCD, and phobias
  • Reduce intensity and can be taken routinely or during increased anxiety
  • Depress subcortical CNS levels and have a calming effect
  • Benzodiazepines (-am):
    • Examples: lorazepam, diazepam, and alprazolam
    • Used to treat anxiety, seizures, alcohol withdrawal, muscle relaxation, and relaxation before general anesthesia
  • Barbiturates (phenobarbital) are not often used due to addiction and narrow therapeutic window:
    • Control seizures
  • SSRIs:
    • Examples: celexa (citalopram), fluoxetine (Prozac), and sertraline (Zoloft).
  • SNRIs:
    • Example: Venlafaxine
  • Tricyclic antidepressants:
    • Example: Amitriptyline
    • these may not work as quickly as CNS depressants but they have very little dependence issues
• Insomnia Medications: Non-narcotic benzodiazepines (zolpidem/eszopiclone)
  • Promote sleep with fewer side effects and target areas promoting sleep without depressing the entire CNS
• Barbiturates and Antiseizure Medications:
  • Hydantoins delay sodium crossing neural membranes
    • Reduces potential for excessive electricity and calms the cell
    • Drug of choice for tonic-clonic (grand-mal) and partial seizures (phenytoin)
  • Phenobarbital treats tonic-clonic and febrile seizures in children
  • Succinimides (ethosuximide) delay calcium movement and relax nerve cells
    • Drug of choice for absence (petit mal) seizures
  • GABA (neurotransmitter) inhibits abnormal electrical activity in the brain.
    • Increased presence of this amino acid decreases seizure activity
    • Example medications: vigabatrin, diazepam, Gabapentin, lamotrigine, tiagabine, topiramate, and carbamazepine which suppress abnormal electrical activity

Medications for Behavioral, Emotional, and Mood Disorders

• Central Nervous System Stimulants:
  • Treat ADD, ADHD, obesity, and sleep disorders (narcolepsy)
  • Stimulants calm these patients and increase focus
  • Examples: amphetamine/dextroamphetamine (Adderall), pemoline (Cylert), and methylphenidate (Ritalin)
    • Amphetamine can be prescribed for obesity (30-60 minutes before meals) - increases meabolism
    • Phentermine (Zantryl) is primary treatment for patients with narcolepsy
    • Modafinil (Provigil) and armodafinil (Nuvigil)
• Antidepressants:
  • Treat:
    • Excess sleeping, eating, inability to concentrate, avoidance of companionship, decreased interest in sex/activities, and feelings of despair
    • Neurotransmitters depleted, mood becomes depressed
• MAOIs (monoamine oxidase inhibitors) inhibit MAO
  • MAO terminates neurotransmitter action, stopping it improves neurotransmitters at the site
    • Example: selegiline (Eldepryl)
• Dietary restrictions of foods containing tyramine (critical hypertension)
• Examples: avocados, bananas, beer, high nitrate meat, chocolate, aged dairy, fava bean, figs, herring, hot dogs, papayas, raisins, soy sauce, wine, and yeast
• TCA (tricyclic antidepressants)
  • Keeps norepinephrine and serotonin at the nerve terminals for electrical impulses -Amitriptyline (Elavil) is a drug of choice for severe depression and prescribes to treat insomnia

Selective Serotonin Reuptake Inhibitors (SSRIs)

• Prevents serotonin from being used at the synapse, a chemical in the brain acts as a neurotransmitter
  • Low levels equal depression, keeps seratonin at synapses
  • Fewer effects with drugs prescribed - Examples:
    • Citalopram (Celexa)
    • Fluoxetine (Prozac)
    • Paxil (Paroxetine)
    • Sertaline (Zoloft)
• Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)
  • Blocks reuptake of both seratonin and norepinephrine for increased mood
    • Examples:
      • Venlafaxine (Effexor XR)
      • Desvenlafaxine (Pristiq)
      • Duloxetine (Cymbalta)
    • Fewer effects, commonly prescribed

Mood Stabilizers

• Antimanic agents stabilize mood sifts with bipolar and schizopherenic patients
  • Lithium is a salt used to keep hydration
    • Lithium toxicity requires fatal blood tests (drowsiness, blurred visision, confusion, sensitivty to light, tremors, weakness, cardio, seizures, and coma
    • Lamotrigine (lamictal) and Valporic Acid (Depakene/Depakote)
• Medication for treating psychoses:
  • Disorders characterized by abnormal thoughts, disorganized communication, and lack of interaction with the environment
  • Antipsychotic (neuroleptics) treat behavior

Degenerative Disorders

• Degenerative Medication treatment relieves symptoms and keeps independance as long as poissible
  • Dementia, progressive, irreversible decline in mental function is treated by cholinesterase
  • Anti-alzeheimer agents can be taken with food (Aricept/Donepezil and Rematine)
    • Side Effects such as Diarrhea, headache, and nausea include vomiting, anorexia, and ecchymoses
• Parkinsonson's Disease
  • Degenerative disorder of the CNS, dopamine that causes unorganized movements.
  • Lack of tremors, movement, and rigditiy
  • Focuses acetylcholine at nerves
  • Blood barriers can be difficult to control amount.
  • Dopaminergics (Selegilline Eldepryl, Bromocriptine Parlodel, Carbidopa Levodopa, Akineton) and Cholinergics inhibit the actions of acetylcholine.

Anesthetic Medications

• Local applied to surfaces to numb and block sodium fibers with cream aerosols
• Otic/Optic Drops
• Amides such as Lidocaine and Novacine last longer - Esterics such as procaine/ Tetracaine have potentials

Anesthesia

• IV infusions and inhalations followed y Deslurane, Sevolurane that can supress Cardio.
• CNS depressants
  • Damages liver GI, confusion, Weakness, and Injections for vitamins.