NURS 116 - midterm (look at quiz 1+2) + this

Rheumatoid arthritis (RA) 

  • Arthritis = joint inflammation 

  • RA = chronic systemic rheumatic (inflammatory) disease, autoimmune (immune system attacks the body's own cells) 

  • Risk factors: family hx, gender (female because of estrogen levels) , triggers, can also be triggered by antigens 

  • Causes chronic inflammation of connective tissue 

  • Affected tissue: joints, heart, lungs, kidneys, eyes 

In joints:

  • Dysfunction of the synovial cavity ‘pannus’m

  • Destruction of surrounding tissue (bone, cartilage →articulating cartilage) 

  • Deformity of the tissue 

  • Loss of normal function 

  • Pain 

  • Progressive and autoimmune destruction of healthy endogenous tissue 

S&S: 

  • Synovial joint inflammation: hands, knees, cervical spine 

  • Systemic symptoms (generalized fatugue, anorexia) 

  • BW: will have high C-reactive protein (is a marker of inflammation) 

Tx: 

  • NSAIDs (nonsteroidal anti-inflammatory drugs - reduce pain, inflammation and fever) PO

  • Glucocorticoids (reduce inflammation and immune response) PO

Tx: 

Drug class: BRMs (biologic response modifiers( 

  • Biologics; IV, SC (not PO because they would be destroyed in the GI system) 

  • Inhibits pro-inflammatory cytokines (ex. Interleukins, integrins) → decrease T and B cells response 

  • Drugs: infliximab, Adalimumab, Ustekinumab 

Drug class; DMARDs (disease modifying anti-rheumatic drugs) 

  • Inhibits nucleotide synthesis (decrease replication) 

  • Inhibits WBC synthesis and function 

  • Used for chronic inflammatory disease 

  • Drugs: methotrexate 


Osteoarthritis (OA) 

  • Degenerative disorder of articular cartilage 

  • Risk factors: mechanical stress (too much stress on joints, think athletes), obesity (too much weight bearing on joints), age (anyone can get it), gender 

  • Called wear and tear arthritis → few joints affected than in RA (not systemic) 

Cartilage changes occur:

  • Repetitive pro/inflammatory mediator release (cytokines, prostaglandins) → chronic inflammation 

  • Decreased proteoglycans (meshwork in joints) 

  • Weakened collagen 2 network, and collagen 5 increases (chronic inflammation) 

  • Cartilage tissue destruction → bone-bone in articulating surface 


Tx:

  • NSAIDS, glucocorticoids 

  • Local glucocorticoid administration useful 

  • Glucocorticoid, intra-articular injection drug: betamethasone (celestone): made to stay low in bioavailability and systemic circulation, usually done under ultrasonic light 


Inflammation 4 


IBD - chronic inflammatory bowel disease: Crohn’s disease and Ulcerative Colitis (UC)

  • Risk factors: family hx and triggers (environmental, bacterial)

  • Autoimmune effect: GI cells targeted by an atypical immune response 

  • Systemic S&S: fever, anemia (low oxygenation in the blood), fatigue (and malabsorption), weight loss, rash 

  • Chron’s disease: anywhere within the GI tract (isnt intact so pathogens are able to enter) 

  • UC: large intestine 

Tx: 

  • Drug classes 

  • Glucocorticoids (good for flare ups, don't use long term)

  • Aminosalicylates 

  • DMARDs (methotrexate) → decrease immune response, is potent, give in low doses 

  • Stem cells research (mesenchymal stem cells) 

**crohn's disease has patchy skip leisions 

** sometimes with UC you can treat locally at the rectum because it usually starts there 


Drug Class: aminosalicylates 

  • Drug: sulfasalazine (azulfidine, salazopyrin) 

  • PO administered, metabolized in the colon → active metabolites

  • 5-ASA: salicylate (NSAID) 

  • Sulfapyridine: immunomodulatory activity (DMARD) 

  • Drug: 5-ASA (asacol, teva, mesalamine) → PO, rectal, is an NSAID 


Asthma (aka bronchial asthma) 

  • Chronic inflammatory airway disorder (not autoimmune) 

  • Risk factors: family hx, atopy (presence of other associated allergies) 

Etiology: 

  • Noxious stimuli trigger that is present in the lungs (allergens, particles, infections, stress) 

  • Reactivity of the airways to the stimulo leading to chronic hypersensitivity 

  • Chronic inflammatory changes in the epithelial tissue of the lungs 

  • High goblet cell activity (mucous) 

Presentation: 

  • Bronchial inflammation 

  • Bronchoconstriction (narrows airway) 

  • Mucous production (blocks airway) 


Asthma challenges 

  1. Chronic bronchial inflammation 

  2. Risk of acute attacks (sudden extreme inflammatory response) 

  • Tx focus: stabilizing the bronchial inflammation and minimizing the number fo attacks 

  • Avoidance of triggers 

  • Daily maintenance drugs to decrease bronchial inflammation (controllers)

  • Correct administration technique (inhalation equipment: inhalers) 

  • Immunizations to decrease respiratory infection risk 

  • Recognize the S&S of an attack quickly  

  • Asthma attack drugs: rescue drugs (relievers) 

  • 911 if attack persists 


Tx; controllers 

Anti-inflammatory drugs, inhaled:

  • 1st line maintenance treatment daily 

  • Prophylaxis against attacks 

Drug class: glucocorticoids 

  • Drug: pulmicorte (budenoside), qvar (beclomethasone), flovent (fluticasone) 

Adjunct treatment 

  • Mast cell stabilizers (ex. cromolyn) 

  • Leukotriene modifiers (ex.singulair) 


Long term maintenance: biologics (antibioties) 

  • Xolair (omalizumab) 

  • SC 

  • High affinity for free IgE, decreases expression of mast cell bound IgE, reduction in allergic inflammation 


Asthma attack

S&S:

  • Wheezing, shortness of breath, decreased/no air entry into lung lobes 

  • Tachycardia (increase HR, increase BP) 

  • Anxiety, panic 

  • Fatigue 

Patho: 

  • Limited inspiration and longer expiration phase leads to air being trapped in the alveoli 

  • Leads to hyper-inflated lungs with low gas exchange 

  • Ventilation-perfusion mismatch 

  • Hypoxemia and hypercarbia 

  • High pulmonary pressure → increased RVED → low CO 


Tx: rescue 

Bronchodilator drugs, inhaled 

Drug class: beta 2 adrenergic agonists 

  • Potent, high receptor affinity 

  • Stimulates SNS B2 receptors 

  • Fast acting 

  • Drugs: salbutamol (ventolin) 

Drug class: anticholinergics 

  • Less potent 

  • Antagonize PNS 

  • Slower onset of action 

  • Synergy with beta2 adrenergic agonists 

  • Drug: atrovent (ipratropium) 

**typically will use BOTH albutamil and atrovent together 

** BUT if airway is completely closed these wont work because they cannot reach the lungs 


Severe attack, ER admission; S&S: life threatening 

  • O2

  • Beta2 adrenergic agonists, inhalation (nebulizer), ventolin 

  • Calcium channel blocker (smooth muscle) magnesium sulfate, IV 

  • Anticholinergics, inhalation (nebulizer), synergy treatment 

  • adrenergics/sympathomimetics, IV (epinephrine) 

  • Glucoroticoids, IV 


Magnesium sulfate, IV 

  • Drug classes: electrolyte, enzymatic activator, calcium channel blockers 

  • Inhibition of Ca channels in smooth muscle → reduces cellular excitability → bronchodilation

  • Stabilization of mast cells and t-cells → decreased pro/inflammatory ,ediators 

  • Enhanced release of NO → vasodilation, pulmonary dilation = improved gas exchange 

  • Titrate to effect for severe bronchoconstriction 

 



 Pain 1 

Acute pain is normal physiology its a warning mechanism!!


Assess pain as symptom 

  • LATERSNAPS: location, associated symptoms, timing (onset, duration) 

  • Mechanism (with onset: ‘how did it start?’ → tells you how you should treat based on how it happened) 

  • Severity: “how bad is your pain?” → scale of 0-10, pediatrics = face tool 

  • Associated S&S (ex. fever) 

  • Radiation anywhere? ‘Referred pain’ 

  • Assess pain when taking vital signs, we need to establish a baseline 




** sensors in the epidermis, dermis, and visceral organs 


Afferent pathways 

Sensory information from PNS to CNS:

  • ‘afferent’

  • starts at the sensory receptor/s in a specific body part

  • ends in the CNS’s Somatosensory Cortex

  • the sensory impulse needs to be strong enough to reach a threshold => action potential is initiated (if not strong enough, then no action = no pain message, -50mv is threshold) 

  • nociceptor (in skin, bones, blood vessels, visceral organs) => 1st order neuron (PNS)

  • Sensitization → pain gets less worse over time 


PNS → CNS 

  • Nociceptors → A OR C NERVE fibers pf the PNS (1st order neuron) → spinal nerve → dorsal root and ganglion → posterior horn synapse (substance P neurotransmitter) → 2nd order neuron - decussate (cross over) → ascends spinal cord’s white matter column vis the ‘spinothalamic tract’ (lateral) → thalamus (relay station) → synapse with 3rd order neuron → somatosensory cortex in the brain ‘localization’: specific body part of the sensory homunculus → awareness!

** typical cutaneous nerve: A alpha = fastest transmission. C= slowest transmission (gate control theory) 


Somatosensory cortex: sensory homunculus

  • Maps the cortex region per anatomical body part (based on innervation #s) somatosensory association areas: link the sensation to previous experiences 

  • More sensitive = more nociceptors


Large stimuli may trigger many or all receptors → high awareness of pain 

  • Ex.trauma (tissue tearing): pressure receptors, free nerve endings = big inflammation to the point where tissue is ripping (the bigger the message the more ripping) 

  • Ex. temperature (ex. Blood present) 

 


Non-pharmacological techniques 

Decrease inflammation and sensation: PNS 

  • Ice ( perfusion to tissues, excitability of nociceptors, cellular function) 

  • Pain is a warning mechanism, you cant just treat the pain you have to figure out what is causing it)  

Alleviate the trigger (PNS): 

  • massage - muscle spasm 

  • Physiotherapy : jointm muscle, tendon 

distraction/behaviour modulation: CNS 

  • CBT- cognition behaviour therapy 

  • Activities 


Pain terminology 

Location:

  • Visceral pain – deep pain, organ related

  • Cutaneous pain – superficial, surface related


  • Referred pain – due to body surface innervated by the same spinal nerve/nerve plexus (divides into different nerve innervations)+ interneuron communication (radiating pain - nerves come from the same plexus)

  • Reflexes - e.g. withdrawal reflex

  • Chronic pain – persistent pain

Neuropathic pain – persistent nerve irritation, difficult to tx

  • e.g. allodynia (pain caused by a non-painful stimulus)

  • e.g. hyperalgesia (hypersensitivity to a painful stimulus)

  • e.g. paresthesias (‘pins & needles’) 

  • can occur with decreased perfusion of a nerve, positional


Phantom pain – neuropathic pain post amputation

  • spinal cord neurons are still active despite the lack of stimulus (no nociceptor), interneurons are still communicating pain

  • often leads to chronic pain


Dermatomes - clinical application 

  • Cutaneous segments serviced by the same spinal nerve, clinically assessed to determine sensory/motor pathways 


Reflexes: flexor ‘withdrawal’ reflex 

  • Stimulus (sharp pain) → reflex to withdraw without cerebral control: activation of a sensory neuron (afferent) – interneuron (at level of stimulus in CNS) - automatic activation of a motor neuron (efferent) - response by the effector; awareness 


Acute vs chronic pain 

Acute pain < 10 days

  • Self-limiting - modulator neurotransmitters are released to desensitize the pain 

  • Endogenous modulators secreted

  • can persist but improving

  • SNS responses are active

  • Innate protective mechanism

  • Appropriate tx is effective

  • Persists but improves 


Chronic pain > 6 months

  • Likely travels along C fibres

  • Neurogenic inflammation => pain

  • outcome of e.g. under-treated acute pain, chronic inflammatory disorders

  • Not self-limiting

  • Endogenous modulators are absent

  • SNS responses not active



  • Destructive mechanism, not beneficial to the host

  • yields other dysfunctions: insomnia, anxiety, anorexia, depression, …

  • Treatment requires many modalities e.g. CBT p.1269


 Endogenous neurotransmitter modulator ‘neuromodulators’: efferent pathway 

  • endogenous opioid peptides: endorphins, enkephalins, dynorphins

  • serotonin & norepinephrine

  • released from the CNS: hypothalamus, limbic system, reticular formation

  • DESCENDING (efferent) pathway

  • bind opioid receptors (mu, kappa, delta) => inhibit substance P

  • Substance P: excitatory CNS neurotransmitter

  • propagates pain input


Pain 2: pain management - opioids

Opioids

  • OPIUM- naturally occurring milky extract from the unripe seeds of the poppy plant. Contain morphine and codeine substance (and other 18 substances) 

  • OPIATES- naturally occurring chemical compounds extracted from opium, natural 

  • OPIOIDS- any drug that is derived from the opium formula, synthetic or natural  

  • NARCOTICS- morphine like drugs that produce analgesia and CNS depression, terminology is associated with illegal use (hallucinogen, heroin, amphetamines, marijuana) 

  • These terms opiates/opioids/narcotics analgesics are used unterchangeably 


Opioids 

Purpose:

  • Remain therapeutic mainstay for moderate to severe pain management 

  • May be combined with other therapies to manage chronic or complicated pain 

Titration purpose:

  • MOST opioids have No ceiling doses (titrate dose as high as you need but that leads to abuse)  

  • Titrate upward as needed 

  • All will cause dependance 

  • Titrate downward as soon as patient can tolerate 

Drug schedule:

  • Regulated 

  • Most are schedule 1 while some are schedule 2 


Opioids 

  • Opioids are agonists for receptors mu (1 and 2), kappa, delta, sigma, and epsilon (opiate) 

  • When the synaptic knob at the primary or secondary synapse is activated by an opioid agonist, it will inhibit release of pain neurotransmitters such as substance P and glutamate 

SUBSTANCE P:

  •  involved in acute pain transmission (focus)

  • opioids act at the mu or kappa receptors which inhibit the release of substance P

  • this inhibition reduces depolarization of ascending pain neurons, thereby blocking pain transmission 

OPIOIDS AND DOPAMINE :

  • Dopamine release in the mesolimbic reward pathway (ventral tegmental area → nucleus accumbens prefrontal cortex) contributes to the rewarding and reinforcing effects of opioids 

  • This results in a calming or pleasurable sensation 

  • However, dopamine is nor directly responsible for analgesia but plays a role in addiction and reinforcement 


Opioids 

ADME

  • ABSORPTION - variable depending on the route of administration (PO, IV, TD) 

  • DISTRIBUTION -   distributes to skeletal muscle, liver, kidneys, lungs, intestinal tract, spleen, brain. Adults: 20% to 35% protein binding (not heavily PPB). peak plasma concentration ( oral → 1h, IV → 20mins) 

  • METABOLISM - Hepatic vis conjugation 

  • ELIMINATION - via urine and feces, metabolites might cause toxicity with renal insufficiency 

Opioids


Opioid receptor 

Effects 

Other 

Mu 1 



Mu 2

Analgesia, euphoria, confusion, dizziness, nausea , sedation 


Respiration depression, cardiovascular effects (hypotension), GI effects (slow motility), urinary retention, Miosis (constriction of pupils) 



Histamine release, dopamine release

delta

Analgesia, cardiovascular effects, respiratory depression 

kappa

Analgesia, psychometric effect (nightmares) 


Opioids 

Opioids based on efficacy: 

-high efficacy ex

  • Fentanyl (80-100 times more potent than morphine) → TD, IV, highly potent (dont give out as easy), used in post op pain

  • Hydromorphone (dilaudid) - 5x stronger than morphine →post-op, cancer treatment, less histamine release (less itching) 

  • Meperidine (demerol) → seizures 

  • Morphine → more histamine (itching) 

  • Methadone (metadol) → opioid addiction and chronic pain 

-moderate efficacy ex

  • Hydrocodone, oxycodone (oxyneo), oxycontin, tramadol (ultram) 

  • Combo drugs: percocet, percodan, vicodin, tramacet 

  • Codeine (no to kids- codeine is pro drug, that get changed to morphine when being metabolized, kids metabolism is not reliable) 

  • ️high benefit = high risk 


Opioids 

Combination drugs:

  • Opioid + non narcotic analgesic (synergistic effect: Drug A + Drug B = synergistic effect) 

  • Benefit - dependance on opioid can be reduced 

Ex. 

  • Percocet (oxycodone + acetaminophen) 

  • Percodan (oxycodone + ASA) 

  • Vicodin ( hydrocodone + acetaminophen) 

  • Tramacet (tramadol + acetaminophen) 

  • Atasol (acetaminophen + caffeine + codeine) 

  • Tylenol #1 - #4 (amount of codeine present) 


Opioids 

Side effects:

Central nervous system (CNS)

  • CNS-depression -drowsiness, dizziness, confusion, or menta; clouding 

  • Excessive sedation or unresponsiveness in high doses 

Respiratory system 

  • Respiratory distress (slow, shallow breathing) 

  • Apnea in severe cases 

Cardiovascular system 

  • brady cardia in most cases, tachycardia during compensation (when body is trying to deal with the decrease in CO and the side effects) 

  • Hypotensio or palpitations 

Gastrointestinal system

  • Constipation due to slower intestinal mobility 

  • Nausea, vomiting, or reduced appetite 

Genitourinary system 

  • Urinary retention 

Integumentary system 

  • Pruritus bc of histamine  


Opioids 

Side effects 

  • Nausea and vomiting: usually resolves in a few days; antiemetics, switch opioids 

  • Sedation: mostly during unutation or change in dose, decrease dose 

  • Constipation: most common and should be anticipated, stool softeners, osmotic stimulants, peripherally-acting mu-opioid antagonists, switch opioids; avoid bulking agents 

  • Pruritus: switch opioids, antihistamines 

  • Urinary retention: switch opioid


Morphine 

  • Class; opioid analgestic/ opiate receptor agonist 

  • Dose form: tablets; parenteral 

  • MOA: opioids bind to opiate receptors (mu, Kappa, delta) in the CNS, where they act as agonists of endogenously occurring opioids (enkephalins, endorphins, and dynorohins), reducing perception of and response to pain 


Indicators 

Management of moderate to severe pain 

Contraindications 

Hypersensitivity. Severe respiratory disease. Head injury. 

adverse/common side effects 

Severe respiratory/ CNS depression (most common in those who are opioid naive). Constipation. Urinary retention. Pruritus. 

What you need to assess

Assess type, location and intensity of pain prior to and at peak following administration. Use equianalgesic chart when changing routes, or from one opioid to another.

Education for patient 

Instruct patient on how and when to ask for pain medication. May cause dizziness or drowsiness. Make position changes slowly. Avoid concurrents use of a;cohol or other CNS depressants 


naloxone/narcan 

  • Respiratory depression is seen in less than 10% of opioid users, almost always in those who are naive to opioid therapy (have not been giev opioids for more than 7 days in a row) 

  • Indication- when the respiratory rate falls below 8-10 and teh client has altered mental status, nalozone will be given to reverse the opioids effect 

  • MOA- narcan blocks mu and kappa receptors 

  • Administration - it should be given carefully, and administered slowly just until the client starts ti respond with increased respiratory rate and a clearing mental status 

  • Onset - 2-4 minute (secure ABC’s) 

  • Duration of action - 45 min 

  • NOTE: if thus drug is given to chronic opioid user, the client will also wake up i aggressive behaviour (euphoria). Because they were on drugs to get rid of pain and you stopped it 


Naloxone 

  • Brand name - narcan 

  • Class - opioid antidote (antagonist) 

  • Dose forms - parenteral; intranasal 

  • MOA - competitively blocks the effects of opioids, including CNS and respiratory depression, without producing any agonist (opioid-like) effects


Indicators 

Reversal of CNS depression and respiratory depression due to suspected opioid overdose 

Cotraindiccations 

Hypersesitivity 

adverse/ common side effects 

Ventricular arrhythmia 

What you need to assess 

Monitor respiratory rate, rhythm and depth; pulse, ECG, BP and level of consciousness frequently for 2-4 hours after expected peak. Diluted and administer in slow increments for sensitive patients (<1 week opioid use). Assess for signs of opioid withdrawal 

Education for patient 

As medication becomes effective, explain purpose and effects to patients 


Nursing considerations

  • Adequately assess pain 

  • Treat pain holistically 

  • Treat all patients adequately 

  • Base the treatment plan on the patients stated goal 

  • Use pharmacological and non-pharmacological pain strategies 

  • Use a multimodal approach to pain management 

  • Regularly monitor pain management strategies to ensure patients goals are being met 

  • Continually educate and inform patients about the medications


Pain management 

<4/10 

  • Non opioid medications

  • Less invasive route, ex. PO 

  • NSAIDs, Tylenol (or both →to get a synergyst effect)  

4-6/10

  • Opioids 

  • Less invasive route, ex. PO 

  • Synergy, combination drugs, morphine 

>6/10 

  • Higher potency opioids 

  • Consider IV route 

  • Consider PCA (patient control anergisia) 


Pain management 

  • The PCA (patient controlled analgesia) device is a programmable syringe pump, which delivers the opioid infusions according to individualised settings: bolus dose, lockout time, dose duration, background infusion 

  • Only if ABC’s are intact can the patient be in controll


Nurses and pain management 

  • Each of us filter our understanding of pain through our own experiences 

  • Personal use of medications or non-pharmacologic methods to manage pain 

  • Family or significant others’ history or experience with substances for pain control or mood altering effect 

  • Remember that pain is an individual subjective experience, and “is what the patient says it is”


Pain 3 

  • Preparations for each administration is called a formulation 

  • Advocate for your patient - best route available 

  • PCA is a delivery method NOT route 

  • PCA - patient has control over giving themselves a little boost 


Pain and pain treatment 

  • Cause?

  • Tx: risk vs benefit, consider synergy 

  • monitor : efficacy of pain tx, side effects, adjunct tx (other therapy for a better job) 

  • To alleviate anxiety around pain, treat the underlying cause/find 

  • Synergy - using 1+ drug for the effect of them together additional effect 

  • Higher potency = high affinity to drugs = side effects 


Pain tx : analgesia (umbrella term) 

synergy tx is common:

  • the interaction of 2 or more drugs when their combined effect is greater than the sum of the effects seen when each drug is given alone (adaptive effect) 

  • lower doses/drug to create an effect (good! likelyhood of negative side effects) 

  • tx at peripheral (PNS) level: high efficacy if inflammation is present (NSAIDS (anti inflammatory), glucocorticoids (COX inhibitory))

  • tx at CNS level: Opioids: potency (mg or mcg!!!), Tylenol (acetaminophen)


Acetaminophen (tylenol) 

Centrally acting analgesic 

  • Not anti-inflammatory 

  • Synergy 

  • Combined into >600 combination medications (ex.opioid Tramacet) 

MOA as analgesic: many theories ex. 

  • Interferes with PGs but not at peripheral level = not anti-inflammatory 

  • Agonizes cannabinoid receptors (inhibitory effect on brain) 

  • Antipyretics #1!!


fever : pyrexia 

  • A nonspecific response to a threat 

  • hypothalamic response to pyrogens: exogenous &/or endogenous

  • exogenous: bacteria-produced, e.g. endotoxins

  • endogenous: inflammatory mediators e.g. cytokine → body can produce 

  • aim: destruction of pathogen by high temperature → basal metabolic rate (BMR)

  • high temperature: increases BMR, decreases cellular fx (proteins and enzymes may not like increase in temp), uncomfortable

  • symptom only: non-specific; what is the cause/the diagnosis?


Tx: antipyretics 

  • Goal: patient comfort, decrease BMR, optimize cellular function 

Acetaminophen (Tylenol)

  • 1st choice, best efficacy

  • MOA: induces hypothalamic-peripheral vasodilation (inhibits ProstiglandinE2)=> heat loss

  • safe in pediatrics (mg/kg, kid measurements) & in pregnancy

  • Liver issues don't mix with tylenol 

NSAIDS (Ibuprofen, ASA)

  • anti-inflammatories reduce cytokines => decreased pyrogenic stimuli

  • no ASA in pediatrics

other tx:

  • Tx of the cause (e.g. infection)

  • hydration

  • congestion, cough, rhinitis, diaphoresis (sweating)….


Acetaminophen in combination drugs:

  • Always check label for active drug ingredients

Allergy-related symptom tx: antihistamines

  • drugs: diphenhydramine, chlorpheniramine

Cough tx: antitussives

  • Coughing is a protective innate response, sometimes it is good 

  • CNS depression of cough reflex

  • Caution – not always desirable

  • drugs: Codeine (opioid, CNS sedation, coughing reflex); Dextromethorphan (robitussan) 

Congestion tx: adrenergic agonist (sympathomimetic)

  • SNS stimulation decreases nasal secretions

  • Drugs: Ephedrine, Pseudoephedrine

  • More selective in binding 

Menthol as an analgesic 

  • activates cold-sensing receptors

  • MPA - topical 

  • not actually cold but cooling effect

  • Gate Control theory (works on pain receptors) → inhibitory interneuron: reduction of the sensation of pain through the inhibitory interneuron being activated within the spinal cord 

  • Inhibitory interneurons signalling back and override that sensation of pain 

  • Buckleys medicine “it tastes bad but it works” 


Drug combo: 

Robaxacet 

  • ‘Robax’: muscle relaxant (methocarbamol) →MOA is unknown 

  • ‘Axet’: acetaminophen (analgesic) 

  • Helps with back pain (tylenol), muscle spasms + tense neck muscles + strains and sprains →relaxing piece 

  • Is a CNS depressant → of SNS therefore allowing for muscle relaxant (drowsiness, no heavy machinery, do not mix with other CNS depressants

Robaxisal 

  • ‘Robax’: muscle relaxant (methocarbamol) →MOA is unknown 

  • ‘isal’ : Acetylsalicylic acid → pain relief 



Barriers to pain relief: be aware of them 

  • Healthcare professionals: acute pain <10 days, acuity of pain will decrease over time if you are treating the cause of the pain 

  • Patients: denial, not voicing pain (culture), dont want to get addicted/ past of addiction 

  • Healthcare system: portects patients, tracks patient history (see patterns), hinder acute pain (who provides drugs, credentials, ect) 

  • Fear of creating addiction 


Euphoria: psychological addiction + physical addiction 

  • Physical addiction: happens at the receptor level. A substance is causing a receptor response, because of that receptor responds it is triggering a series of events to take place within the body but the patient is not actively seeking that drug for a high. Treat with weaning protocol 

4 C’s of psychological addiction 

  • Cravings 

  • Compulsion to use 

  • Loss of Control over use 

  • Use despite harmful Consequences 

  • Is a change in behaviour to have that substance as much as possible


Acute vs chronic pain 

Acute pain < 10 days

  • Self-limiting - modulator neurotransmitters are released to desensitize the pain 

  • Endogenous modulators secreted

  • can persist but improving

  • SNS responses are active

  • Innate protective mechanism

  • Appropriate tx is effective

  • Persists but improves 


Chronic pain > 6 months

  • Likely travels along C fibres

  • Neurogenic inflammation => pain

  • outcome of e.g. under-treated acute pain, chronic inflammatory disorders

  • Not self-limiting

  • Endogenous modulators are absent

  • SNS responses not active



  • Destructive mechanism, not beneficial to the host

  • yields other dysfunctions: insomnia, anxiety, anorexia, depression, …

  • Treatment requires many modalities e.g. CBT p.1269


Chronic pain 

  • Repetitive and altered SNS initiation of responses → chronic inflammation + chronic pain cycle 

  • How to assess chronic pain? Length of time, location/site that is stimulating the pain, always try to reassess the pain and see if you missed something 

Ex. CRPS

  • CRPS: complex regional pain syndrome

  • Allodynia 

  • Skin changes to the injured area: hair loss, temperature changes, color changes

  • Muscle and joint stiffness 

Treatment of Chronic Pain 

  • What is the underlying dx? appropriate tx?

Chronic pain clinics

  • counselling: CBT

  • physiotherapy

CNS drugs

  • ! Opioids: not 1st line in chronic pain (too addictive) 

  • Decrease excitatory neurotransmitters

  • drug: Gabapentin (Gabarone)

  • NMDA antagonists: NMDA receptor binds glutamate (excitatory neurotr.)

  • Enhance serotonin

  • Certain antidepressants which increase serotonin (serotonin modulates pain)


Efficacy overview

  • Treatment of inflammation: allergy, antihistamine 

  • Tissue injury: NSAIDS, glucocorticoids, disease specifics (DMARDS 

  • Bronchoconstriction: beta 2 adrenergic agonists 

  • Treatment of pain: acetaminophen, NSAIDS, glucocorticoids, opioids 

  • Treatment of fever: acetaminophen, NSAIDS