Central Nervous System Drugs Flashcards
Cerebrum
Thinking portion: Perception, Speech, Conscious motor movement, Skeletal muscle movement, memory, smell
Higher brain functioning
Thalamus
All nerve endings come here
Relay center: Sounds, sights, pain, touch, temperature.
Sends out motor response - needs to go back to the had to tell it to take it off the burning iron
Controls mood and motivation
- Associated with bipolar, anxiety, panic disorder, OCD
Hypothalamus
Ventral to Thalamus
Controls homeostasis
Major visceral control center: Hunger, thirst, water balance, body temp
Part of limbic (emotional balance)
Connection with brainstem (HR, RR, BP, Pupil size)
Plays a big part in the autonomic system
Cerebellum
Little brain at base of brain
Controls: Muscle movement, balance, posture, tone
Recieves info on vision, position, equilibrium, touch, and calculates strength
Injury results in uncontrolled jerkiness
A lot of Parkinson drugs work here
Brain Stem
Connects spinal cord to brain
Medulla oblongata (A lot of vital signs are regulated here), pons and midbrain here
Major relay center
Major reflex and control center: Breathing, Heart rate, swallowing, coughing, vomiting, vision
Spinal cord
Transmits to and from brain
Disruption: Paralysis, Paresthesia
Afferent nerves - to the brain
Efferent nerves - away from brain
Limbic system
Group or series of brain pathways
Responsible for emotion and mood
Some pain meds designed to effect Limbic system due to the emotional factor or pain
Reticular Activating System
Responsible for heightened alertness
Sleep meds designed to slow down RAS
Some motor units involved
Basal Ganglia
Responsible for Posture and movement
Cognitive function.
Blood brain barrier
Protects brain from pathogens and toxins
Supplies Oxygen, glucose, and nutrients
CNS drugs must penetrate
Neuron parts
Dendrites come before cell body
Carry message to the cell body
Cell body interprets message and pushes info down the axon.
Transfers to another nerve through the synapse
Monoamines
Dopamine. Epinephrine, Norepinephrine, Serotonin.
Amino Acids
Asperate, Aminobutyric acid (GABA), Glutamate, Glycine.
Gamma Aminobutyric acid (GABA)
Inhibits over excitation of brain
Slows things down
Used for seizure medication and sleep disorders
Opiod peptides
Dynorphins, Endorphins, Enkephalins
They are endogenous; therefore the body makes it’s own opium.
Nonopioid peptides
Neurotensin, Oxytocin, Somatostatin, Substance P, Vasopressin
Substance P
Pain control
Acts as a neurotransmitter
Has a role in interpreting pain
Has a role in regulating self produced endogenous analgesic response.
Big reason why we have different pain tolerance levels.
Actions of drugs
Blocking the reuptake of neurotransmitters
Blocking the enzymes that break down the neurotransmitters
Stimulating specific receptor sites when neurotransmitter is unavailable
Stimulating presynaptic nerve to release greater amounts of neurotransmitter
Pain definition
Whatever the experiencing person says it is and wherever he says it does.
An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.
Four phases of pain
Transduction
Transmission
Perception
Modulation
Transduction
Stimulation of first nerve; at the site of injury
Injured tissue release chemicals that propagate pain messages such as prostoglandins or kinnins or histamines (become neurotransmitters)
Neurotransmitters stimulate or sit on nociceptors (nerve ending) located on skin, connective tissue, muscle, circlulatory system, thoracic, abdominal, and pelvic areas.
Stimulated by trauma, injury or chemical mediators.
Stimulates first nerve
Transmission
Nerve 1 to the spinal cord then to the brain
Pain stimuli enters spinal cord in the dorsal horn
Substance P is released in response to pain (a peptide in the dorsal horn) (Acts as neurotransmitter)
Glutamate and ATP also act as neurotransmitters
Differences here may be why we have different pain tolerances.
Afferent Neurons
Carry signals TO CNS
Pain begins in nociceptors in afferent neurons and gets carried to CNS
Perception of pain
Pain impulse reaches brain
Brain now has a conscious awareness of pain sensation
LIMBIC SYSTEM ACCOUNTS FOR EMOTIONAL RESPONSE
Higher cortical structures will identify as “pain”
Modulation
Brain interprets and decides what to do with the information
Pain message is inhibited through this phase
Descending from brain to spinal cord, we produce another set of neurotransmitters that will impeded pain impulse
Neurotransmitters include serotonin, norepinephrine, neurotensin, GABA, our own endogenous opioids
Modulation of pain
Within spinal cord are opioid receptors called kappa and mu.
Endogenous opioids can block kappa and mu
Exogenous opioids or opioid medications kick off the endogenous opioids because they are stronger and block kappa and mu
If kappa and mu are not blocked then move to thalamus in brain
Opioid Receptors
Mu and Kappa
(And Delta… red headed step child no one cares about)
Mu most important from a pharmacological stand point
Responses of an activated Mu receptor
Analgesic, Respiratory depression, sedation, euphoria, Physical dependence, Decreased GI motility
Responses of and activated Kappa receptor
Analgesic, Sedation, Decreased GI motility, Miosis
Miosis
Pinpoint pupils
Endorphins
endogenous opioids, enkephalins, and dynorphins are made in own body
Released in synapse and bind with opioid receptors on (mu and kappa recepters) dorsal horn to prevent further transmission of painful stimuli.
Nociceptive pain
Pain caused by damage to the body.
Somatic and Visceral
Somatic Pain
Pain to skin, muscle. More superficial. Injury to tissues.
Visceral pain
Dull, throbbing, poorly localized. Deep tissue; organs.
Neuropathic pain
Pain in the nerve pathway. Hardest to treat. Tingling, burning, stabbing, radiates. Usually long term.
Vascular pain
Caused by spasms which cause inflammation which causes pain. Migraines an example
Psychogenic pain
No cause; in patients head
Phantom Pain
Nerve endings still raw from amputation. Brain is interpreting the pain wrong. (Egg.. I mean Leg pain when there is no leg). Will go away within 6 mo-1 year.
Acute pain
Organic cause: Common
Environmental contributions and family involvement: small
Insomnia: Unusual
Treatment goal: Cure
Usually has a physical cause that can be treated
Chronic pain:
Harder to treat than acute. Can be life changing.
Dependence and tolerance to medication is common.
Psychological component: Often a major problem
Organic cause: Often not present
Environmental contributions and family involvement: Significant
Insomnia: Common
Treatment goal: Functionality
Pain lasting longer than 3 mo or longer than medically expected.
Signs of acute pain
Hypoxia
Hypercapnia (Hanging on to CO2 from holding breath)
Hypertension
Tachycardia
Emotional difficulties
If left untreated can lead to chronic pain
Chronic pain - 4 subtypes
- Pain that persists past the normal healing time for an acute injury
- Pain related to chronic disease (arthritis)
- Pain without identifiable organic cause
- Pain that involves both the chronic and acute pain associated with cancer (not worried about them about becoming addicted. We treat differently)
Consequences of unrelieved pain
- Stress hormone response
- Impaired muscle movement
- Quality of life changes (Decreased social relationships, decreased sleep, depression, anger, hopelessness)
Barriers to pain management: The professional
- Lack of knowledge about pain medication
- Misconceptions
- Inadequate assessment
- Concerns about opioids (addiction, respiratory depression, side effects)
Barriers to pain pain management: The patient and family
Stoicism (Lack of reporting pain, pain is weakness)
(Supposedly men complain of pain less then women… apparently they needed to include our husbands in this study)
Concerns about medication (Addiction, just say no, side effects)
Medication administration (confusion about dose, times, etc)
True or false: Pain is a natural consequence of getting old.
False
True or false: Older patients don’t feel pain as acutely as younger
False: Transmission of pain may be altered by chronic disease, but they will still feel it.
True or false: Older patients can’t reliably report pain
False: Make sure hearing aids are in and glasses on if using a pain scale.
What is the first step in pain management??
Assessment!
What do we need to know about the patient’s pain?
Location Severity Type Duration Effect of daily life
What are some non-pharmacological treatments?
Heat for muscle, Cold for acute injury, Accupuncture, Massage, Biofeedback, Guided imagery, Relaxation, Exercise, Trancutaneous Electrical Nerve Stimulation (TENS)
Opioid agonist
Occurs when opioid “Turns on” the opioid receptors. They kick our endogenous opioids off and are able sit on the receptors longer, thus causing better and longer pain relief.
Opioid Agonist Effects
Analgesia, sedation, mental clouding, Euphoria, Respiratory depression, Miosis, Decreased GI movement, Depression of cough reflex, Orthostatic hypotension, Stimulate vomiting reflex.
Opioid Kinetics
Absorption: Good oral (Thats what she said) and Large first pass effect
Metabolism: Hepatic
Elimination: Renal, Feces (With morphine when given PO)
Onset: 15-30 minutes
Duration: 3-7 hours
Opioid Cautions
Contraindicated for patients with a TBI, respiratory depression, pts receiving other CNS depressants, head injury.
Dose reduction may be necessary in elderly due to altered pharmacokinetic properties.
Drug addicts assess case my case. Monitor how much. May give a lower dose.
Opioid Adverse effects
CNS: mood changes, lethargy, delerium, euphoria, pupillary constriction
Respiratory: Decreased RR, Resp Arrest, apnea
Cardiovascular: Hypotension, bradycardia, Cardiac arrest, shock, coma
GI: N/V, constipation
GU: Urinary retention (Watch with elderly men with BPH)
Histamine release: Pruritis and uticaria (May need to give benedryl)