Nervous System Pharmacology

Adrenergic System

• Relates to nerve fibers releasing norepinephrine or epinephrine at synapses.

Analgesics

• Medications that relieve pain.

Autonomic Nervous System

• Self-controlling system that functions independently and unconsciously.
• Maintains homeostasis in the body.

Blood Brain Barrier

• Densely packed cells allowing certain nutrients and chemicals to pass into the central nervous system while blocking others.

Central Nervous System

• Comprises the brain and spinal cord.
• Controls and processes information for the body.

Cholinergic Agents

• Also known as parasympathomimetics.
• Produce the effect of acetylcholine.
• Acetylcholine is a neurotransmitter carrying messages from the brain.

Drug Holiday

• Period when medication is stopped to allow resumption at lower doses with desired benefits.

Gamma-Aminobutyric Acid (GABA)

• Neurotransmitter that slows down the brain by blocking specific signals in the CNS.
• Known for producing a calming effect.

Hydantoins

• Slow synaptic transmission by blocking sodium channels´ recovery from the inactivated state.
• Inhibits neurons from firing, halting repeated excitation causing seizures.

Monoamine Oxidase Inhibitors (MAOIs)

• Prevent breakdown of mood-improving brain chemicals.
• Used to treat depression and mental health disorders.
• Prevents breakdown of serotonin, dopamine, and norepinephrine.
• Makes more of these chemicals available in the brain to improve mood.

Narcotics

• Strong painkillers, usually derived from opium.
• Can be physically and psychologically addictive.

Neuroleptics

• Medications used to treat psychoses.

Neurotransmitters

• Chemical messengers transmitting signals between nerve cells.
• Allows communication and control of bodily functions.

Parasympathetic Nervous System

• Controls the body's relaxation response, known as "rest and digest".
• Slows heart rate, dilates blood vessels, decreases pupil size, increases digestion, relaxes digestive tract muscles.
• Maintains metabolism and helps maintain resting bronchial constriction.

Peripheral Nervous System (PNS)

• Network of nerves throughout the head, neck, and body.
• Carries messages to and from the CNS.

Psychotropic Substances

• Affect how the brain works and causes changes in mood, awareness, thoughts, feelings, or behavior.
• Examples include alcohol, caffeine, nicotine, marijuana, and certain pain medicines.

Selective Serotonin Reuptake Inhibitors (SSRIs)

• Antidepressants that prevent serotonin reabsorption in the brain.
• Increases serotonin availability to regulate mood and brain function.

Somatic Nervous System

• PNS component associated with voluntary body movements via skeletal muscles.
• Responsible for consciously influenced functions, including moving limbs.

Status Epilepticus

• A medical emergency involving a seizure lasting over five minutes.
• Can involve multiple seizures without regaining consciousness and continuous seizure activity without pause.

Sympathetic Nervous System

• Branch of the autonomic nervous system preparing the body for "fight or flight".
• Increases heart rate, blood pressure, breathing rate, and pupil size.
• Inhibits digestion and non-essential functions to help the body respond to stress or danger.

Synapse

• The gap between nerve cells where communication occurs.

The Nervous System

• Central Nervous System: brain and spinal cord.
• Medications work by either exciting or depressing the CNS.
• Peripheral Nervous System consists of the somatic and autonomic nervous systems.

Somatic vs Autonomic

• Somatic controls muscles we have control over.
• Autonomic controls inner organs involuntarily due to stimuli sent to the brain.
• Acetylcholine and norepinephrine are two main autonomic nervous system neurotransmitters.
• Further divided into sympathetic (fight or flight) and parasympathetic (rest and relax).

Autonomic Nervous System Medications

• Sympathomimetics (adrenergic): Stimulate fight or flight, the heart, increase blood flow to skeletal muscles, constrict peripheral blood vessels, dilate bronchi, restore heart rhythm, and increase BP.
• Adrenergic blockers: Calm the nervous system, treat cardiac arrhythmias, high blood pressure, migraines, and chest pain.
• Alpha blockers (-sin): Affect vascular smooth muscle and alleviate HTN and BPH like alfuzosin, doxazosin, prazosin, tamsulosin, and terazosin.
• Beta blockers (-lol): Block epinephrine effects, slow heart rate, reduce BP, and treat HTN, migraines, and glaucoma like acebutolol, atenolol, bisoprolol, metoprolol, nadolol, nebivolol, and propranolol.
• Parasympathomimetics (cholinergics): Mimic PNS, release acetylcholine, relax, and rest but are rarely used.
• Nerve gas, such as Pilocarpine, is an example to treat open-angle glaucoma- drug must be stopped before surgery.
• Anticholinergics or Cholinergic Blockers: Inhibit PNS, promote fight or flight, dry secretions, treat asthma and motion sickness, preoperative relaxation, and insect stings.
• Cholinergic crisis: Often seen in myasthenia gravis and treated with emergency atropine.

Medications for Pain and Fever:

• Analgesics: Reduce pain without eliminating feeling or sensation.

Salicylates

• Aspirin: Relieves mild to moderate pain, reduces inflammation and fever, decreases inflammation in blood vessels, improves cardiovascular flow, but can cause GI distress.
• Methylsalicylate: Topical anti-inflammatory that increases blood flow and decreases pain like Bengay.
• Acetaminophen: Decreases pain and fever but has no anti-inflammatory effect.
• NSAIDs: Reduce pain and swelling caused by inflammation.
• Opioid Analgesics: Strong painkillers that suppress the CNS and are reversed by naloxone

Medications for Anxiety, Insomnia, Sedation, and Seizures:

• Target the limbic system in the brain that is integral to emotions love, fear, anger, memory, alertness

Anxiolytic medications

• Treats generalized anxiety disorder, panic disorder, PTSD, OCD, phobias which reduces intensity, can be taken routinely or during increased anxiety, depress subcortical CNS levels
• Benzodiazepines: (-am) lorazepam, diazepam, alprazolam for anxiety, seizures, and alcohol withdrawal symptoms
• Barbituates: (phenobarbital) not often used due to a high level of addiction and narrow window of effectiveness
• SSRIs: Citalopram, fluoxetine, sertraline
• SNRIs: Venlafaxine
• Tricyclic antidepressants: Amitriptyline does not work quickly but has very little dependence issues

Insomnia Medications

• Non-narcotic benzodiazepines: Zolpidem and eszopiclone helps to promote sleep with fewer side effects

Barbiturates and Antiseizure Medications

• Hydantoins: Delay sodium from crossing neural membranes decreasing its potential.
• Are the drugs of choice for tonic-clonic and partial seizures
• Succinimides: Delay movement of calcium, drug of choice for absence seizures
• GABA: Decreases electrical activity and seizure occurrence
• CNS Stimulants.
• Treat ADD, ADHD, obesity, narcolepsy, and help maintain alertness while helping patients focus on only a few stimuli.
• Examples include amphetamine/dextroamphetamine, pemoline, methylphenidate, phentermine, modafinil, and armodafinil.

Antidepressants

• Treat excess sleeping, eating, inability to concentrate, avoidance of companionship, decreased interest in sex and activities, and feelings of despair
• MAOIs and TCAs: Keep norepinephrine and serotonin at the nerve terminals and help electrical impulses to cross the synapse
• SSRIs: Prevent serotonin from being used at the synapse, decreases depression and Citalopram, Fluoxetine, Paroxetine, Sertraline
• SNRIs: Block reuptake of both serotonin and norepinephrine and increased levels elevate mood

Mood Stabilizers

• Mood Stabilizers: Antimanic agents stabilize extreme mood shifts for bipolar and schizophrenia patients
• Lithium- educate patients not to become dehydrated and to avoid table salt due to toxicity.
• Mood Stabilizers are Lamotrigine & Valporic acid
• Medications for treating psychoses is characterized by abnormal thoughts, disorganized communication, and a lack of interaction

Antipsychotic medications

• Treat abnormal actions, behaviors, nausea, vomiting, dementia, agitation, and spasms, or called neuroleptics
• Chlorpromazine, Clozapine, Thioridazine
• Medications to treat degenerative disorders aims to relieve symptoms and Independence
• Treats Dementia progression with Aricept and other drugs.

Parkinson's Disease

• Focuses on keeping dopamine and acetylcholine at the nerve synapse and promote transmission of nerve signals- Degenerative disorder of the Central Nervous System, causing a lack of dopamine and increased acetylcholine.
• It is difficult to ensure sufficient dopamine reaches the brain due to the blood-brain barrier
• Drug holiday when the dose cannot be increased or the drugs side effects are not tolerable.
• Treats with Dopaminergics and cholinergic agents.

Local and General Anesthetic Medications

• Local anesthetics, blocks the entry of sodium ions into nerve fibers
• Topical anesthetics cream lidocaine/prilocaine and spray with benzocaine/butamben/tetracaine in aerosol spray.
• Amides of local anesthetics are more popular.
• General anesthesia can be received through IV solution and IV solution.
• Alcohol can cause confusion, peripheral vasodilation, increase heart rate, loss of coordination of the body, and unsteady speech
• Signs and symptoms of chronic alcoholism are irritability, tremors, GI disorders
• Treatments include disulfiram, and assess for respiratory problems when withdrawing.