Pain Flashcards
General Anesthetics
Use for major surgery
Induce a reversible state of unconsciousness
Provide amnesia
Anesthesia stage 1
Analgesia,
Still conscious
Somewhat aware
Loss of sensation
Anesthesia stage 2
Excitement,
Unconscious
Amnesiac
Appears agitated and restless
Anesthesia stage 3
Surgical anesthesia,
Ideal level for surgery
Regular, deep respirations
Anesthesia stage 4
Medullary paralysis,
Should be avoided
Cessation of spontaneous respirations
Cardiovascular collapse
Inhalation of anesthesia
Gases or volatile liquids
Longer onset to stage III
Easier to adjust dose and maintain anesthesia
Intravenous route of anesthesia
Several categories of CNS depressants
Rapid onset to stage III
Risk of over medication
Barbiturates in association to anesthetics
Induction of anesthesia
Fast onset
Relatively safe
Opioid analgesics in association to anesthetics
Induction and maintenance of anesthesia
Benzodiazepines in association to anesthetics
Induction and maintenance of anesthesia
Ketamine
Dissociative anesthesia
Patient appears detached from surroundings
Awake but sedated and unable to recall events
Useful for short procedures
less cardiac and respiratory adverse effects
Propofol
Short acting hypnotic
Rapid onset
Induction and maintenance
Rapid recovery
Continuous infusion: sedation of mechanically ventilated patients
Rare adverse effect: Propofol related infusion syndrome (PRIS)
Etomidate
Hypnotic-like drug
Rapid onset anesthetic
Short duration
Quick recovery
Minimal cardiopulmonary side effects
can cause muscle twitching
Dexmedetomidine
Alpha-2 agonist
No respiratory depression
Adjunct during surgery
Short-term sedation for mechanically ventilated patients
Hypotension
Bradycardia
Mechanism of Action – Anesthetics
Inhibit neuronal activity in the CNS (sedation, hypnosis, amnesia)
Inhibit neuronal function in spinal cord (immobility, inhibiting motor response to painful stimuli)
Neuromuscular Blockers
Succinylcholine, Rocuronium, Cisatracurium (Nimbex)
Adjunct to general anesthesia, Skeletal muscle paralysis, blocks nerve impulses.
Neuromuscular Blockers advere effects
Tachycardia
Increased histamine release
Residual muscle pain and weakness
Local Anesthetics (LA)
Loss of sensation in a specific area
Used prior to minor surgical procedures
Rapid recovery with minimal side effects
Local anesthetics MOA
Inhibit opening of sodium channels on nerve membranes
Blocks action potential along neuronal axons
Transdermal – Lidocaine patches
For MSK pain, neuropathic pain
Must have 12 hour “lidocaine free” period each day
Do not apply heat on or near patch (can speed up release and result in toxcitity)
Apply to clean, dry, intact skin
Infiltration Anesthesia
Injection directly into selected
Used for performing surgical repair
Peripheral Nerve Block
Injected close to nerve trunk
Interrupt transmission along the nerve
Used in dental procedures
Minor nerve block
-Single peripheral nerve
Major nerve block
-Several nerves or nerve plexus
Central Neural Blockade
Injected in spaces surrounding the spinal cord
epidural nerve blockade, caudal blockade, spinal nerve blockade
Sympathetic Blockade
Selective interruption of sympathetic efferent discharge
Used for complex regional pain syndrome (CRPS)
Goal is decreased sympathetic outflow, not analgesia
Differential Nerve Block
Local anesthetics block specific nerve fiber groups depending on their size & myelination
Local anesthetic systemic toxicity (LAST)
Early symptoms
Ringing in the ears, agitation, restlessness, decreased sensation in the tongue, around the mouth, and areas of the skin
CNS effects
Somnolence, confusion, agitation, excitation, seizures, impaired respiratory function
Cardiac effects
Decreased cardiac excitation, heart rate, and forced of contraction
Excessive prostaglandins results in…
Inflammation
Pain
Fever
Dysmenorrhea
Thrombus formation
NSAID Mechanism of Action
cox inhibitors
COX-1
Synthesizes beneficial prostaglandins
Maintains cellular hemostasis
Inhibition may cause stomach and kidney issues
COX-2
Produces prostaglandins in response to injury
Selective NSAIDs inhibit only COX-2
Less GI adverse effects
Risk of hypertension, heart failure and infarction
Aspirin
Nonselective cox inhibitor,
Low dose for CV disease prevention
Anti-inflammatory effects require higher dosing than analgesia effects
Ibuprofen (Advil, Motrin)
nonselective COX inhibition, Anti-inflammatory effects require higher dosing than analgesia effects
NSAID Adverse Effects
GI Damage
Cardiovascular Problems
Kidney Damage / Hepatotoxicity
Hypersensitivity
Reye Syndrome
Bleeding risk
Acetaminophen (Tylenol / Paracetamol / APAP) side effects
Analgesic and antipyretic effects
Lacks anti-inflammatory or anticoagulant effects
Not associated with GI irritation
Acetaminophen (Tylenol / Paracetamol / APAP) MOA
Inhibition of cyclooxygenase in the CNS
Acetaminophen dosing
Liver dysfunction
Max dose 2 g/ 24 hours
Normal liver function
Max dose 4 g/ 24 hours
Goals of treatment for RA
Decrease joint inflammation
Arrest progression of the disease
DMARDs
Slow or halt the progression of RA
Used with NSAIDs and glucocorticoids
Highly effective
Significant adverse effects
Antimalarials (Hydroxychloroquine)
Use in combination with newer DMARDs or patients who cannot tolerate newer agents
Adverse effects
High doses - irreversible retinal damage
Headache
GI distress
Immunosuppressant (Azathioprine)
Use to treat severe cases not responding to other agents
Adverse effects
Fever, chills
Sore throat
Fatigue
Nausea, vomiting
Loss of appetite
Leflunomide (Arava®)
Decreases pain, inflammation, and joint effusion
Slows formation of bone erosions
Works early ~ 1 month
Leflunomide (Arava®) adverse effects
GI distress
Allergic reactions (skin rashes)
Pneumonitis
Methotrexate
Antimetabolite used in cancer treatment
Decreases synovitis and bone erosion
Less narrowing of joint space
Used alone or in combination with biological agents
Rapid onset ~ 2-3 weeks
Methotrexate adverse effects
Long term: pulmonary problems, hematological disorders, liver dysfunction
Tumor Necrosis Factor (TNF) Inhibitors (Adalimumab (Humira®), etanercept (Enbrel®), infliximab (Remicade®))
Slow progression of inflammatory joint disease
Improve symptoms and quality of life
Onset of action: months
TNF inhibitors adverse effects
Infections, malignancy, liver disease, heart failure, lupus-like disease, demyelinating disorders
Rituximab (Rituxan)
Depletes B lymphocytes
Beneficial in select patients
Tocilizumab (Actemra)
Blocks the interleukin-6 receptor
Alternative for select patients
Abatacept (Orencia)
Inhibits T cell activation
Used second line
Goals of treatment for OA
Manage pain
Maintain an active lifestyle
Viscosupplementation
Uses hyaluronan to restore lubricating properties of synovial fluid
-Reduces pain and improves function
Temporarily attenuates progression
Responders may benefit for 6-12 months
May delay need for invasive treatment
Well tolerated, pain, swelling, stiffness ~24hr post injection
Glucosamine and Chondroitin Sulfate
Proposed benefit of decreased pain and improved function
Well tolerated
Onset of action: weeks to months
Glucocorticoids for RA adverse effects
Increased bone loss
Muscle wasting, weakness
Hypertension
Aggravation of DM, glaucoma, cataracts
Increased risk of infection
Skin break down
