Non opioid analgesics Flashcards
what are analgesics used for
- relief of acute and chronic dental/facial pain
- non opioid
- preoperative pain
- postoperative pain to reduce expected pain after the dental procedure
what is pain
- common symptom
- body uses it as a defence mechanism: avoid damaging situation and encourage to see medical help
- perception and reaction are individualized: sensory (the actual painful stimulus) and reactionary (the emotional response to pain)
where does the sensory response to pain and the emotional response to pain stem from
- sensory: response to the actual stimulus comes from the peripheral nervous system
- emotional: originates in the central nervous system
what are the 4 types of pain
- fast/first pain
- slow/second pain
- acute pain
- chronic pain
what is neuropathic pain
- due to direct injury to nerves
what is nociceptor pain
- pain due to injury to tissues (somatic pain, visceral pain)
what is somatic pain
- pain that comes from the skin, muscles and soft tissues
what is visceral pain
- pain that comes from internal organs
what are the 2 types of sensory fibers in nociceptors
- a fibers: myelinated, sharp pain
2. c fibers: unmyelinated, dull pain
what is substance p
- a neurotransmitter for pain perception in the spinal cord
- continues or stops the message
what can help control substance p that’s non pharmacological
- endogenous opioids released from the CNS
- decrease pain
examples of non-pharmacological management of pain
- acupuncture
- biofeedback
- massage
- heat or cold packs
- meditation
- relaxation therapy
- art or music therapy
- imagery
- chiropractic manipulation
- hypnosis
- therapeutic touch
- healing touch
- transcutaneous electrical nerve stimulation (TENS)
- energy therapies (Reiki, Qi gong)
examples of non steroidal anti-inflammatory drugs (NSAIDs)
- ibuprofen, naproxen
examples of narcotic (opioid) drugs
- codeine, morphine, diluadid, demerol, etc
what can we use to treat chronic neuropathic pain
- gapapentin (anti-epileptic drugs enhance neuronal stability, which results in pain relief)
- 5% lidocaine patch
- tricyclic antidepressants
- narcotics are not approved for chronic neuropathic pain*
what is the purpose of the inflammatory process
- defense mechanism
- necessary for the body to heal itself (contain the injury or destroy the foreign agent)
- can be acute or chronic
what can cause inflammation
- infection
- allergic reactions
- physical injuries
- exposure to toxic chemicals
- extreme heat
- death of cells
what is chronic inflammation
- can arise from acute case or an injury
- last years, worsen over time
- causes damage to affected sites or internal organs
- body heals - scar tissue forms (can alter normal workings of the body system)
symptoms of inflammation
- redness
- swelling
- heat
- pain
- loss of function
what is the inflammatory process
- damage to tissue
- chemical mediators released
what chemical mediators are released during the inflammatory process
- vasodilation (redness, heat)
- vascular permeability (swelling)
- cell infiltration (pus)
- thrombosis (clots)
- stimulation of nerve endings (pain)
what are prostaglandins
- group of lipids made at sites of tissue damage or infection that are involved in dealing with injury and illness
what do prostaglandins do
- stored and released by mast cells
- increase capillary permeability
- attract white blood cells to site
- cause pain
what is cyclooxygenase and what are the 2 forms
- enzyme that synthesizes prostaglandins
- found in all tissues
- two forms: COX-1 and COX-2
what does COX-1 do
- takes care of normal functions
- protects gastric mucosa
- promotes platelet aggregation
what does COX-2 do
- found at tissue injury sites
- sensitizes receptors to pain
- mediates inflammation
- affects fever and pain perception
- takes care of pain and discomfort
what are some examples of first line pain drugs
- acetaminophen
- aspirin/NSAIDs
what are some examples of 2nd line/pain out of control pain drugs
- opioids (sustained-release of immediate-release)
- NSAID’s
what are some examples of refractory pain medications
- spinal/epidural opioids
- selective nerve blocks
- neuroablative procedures
- total sedation
what are opioids
- morphine like
- narcotic
what does acetaminophen do
- reduces pain by unknown mechanism
- reduces fever by direct action at level of hypothalamus
- causes dilation of peripheral BV -> dissipation
- no anti-inflammatory action
- mild to moderate pain and fever in children
- major advantage is lack of effect on platelet function and less or no gastric irritation
- NOT and NSAID
side effects of acetaminophen
- safe
- no effect on blood coagulation
- no GI irritation
- no malnutrition -> acute toxicity -> renal failure
- hepatotoxicity (liver necrosis)
what are signs of acute toxicity
- nausea, vomiting, chills, abdominal discomfort
what is the maximum dose of acetaminophen in 24 hours
- 4g, with higher doses increasing the risk of liver damage (not more than eight 500 mg tablets in 24 hours)
how are overdoses treated for acetaminophen
- with acetylcysteine
how does acetaminophen react with alcohol
- increases liver damage (hepatotoxicity)
what are the negative effects of inhibiting COX-1
- gastric erosion
- ulceration
- bleeding
- renal damage
what do first generations of NSAIDs do
- inhibit COX-1 and COX-2
- decrease in inflammation, pain, fever
what do second generation NSAIDs do
- COX-2 selective
- reduce inflammation
- reduce pain
- reduce fever
- without side effects of COX-2 inhibition
what do NSAIDs do
- inhibit cyclooxygenase: prostaglandins not formed, prostaglandins cannot activate nociceptors
- for mild to moderate pain, inflammation and fever
what are some advantages to NSAIDs
- over the counter and inexpensive
- different formulations
- safe
what is acetylsalicylic acid
- ASA/aspirin
- originally derived from the bark of willow tree
- today made synthetically
- inhibits both COX-1 and COX-2 (but predominately COX-1), thus many GI problems (bleeding, ulcers)
what is analgesia and what causes it
- the process of reducing pain
- due to inhibition of prostaglandins and bradykinin
- relieves mild to moderate pain (dental)
- ceiling effects (increasing dose beyond a point does not increase analgesia)
what causes the anti-inflammatory process
- drug or substance that reduces inflammation
- due to blocking formation of PGE2 (prostaglandin E2)
what is antipyretic
- used to prevent or reduce fever
- reduces abnormal fever
what are the antiplatelet effects of aspirin
- inhibits lately aggregation (clotting)
- irreversible inhibition of cyclooxyrgenase activity (anticlotting effects last the lifetime of a platelet, which is about 7 days. inhibits clotting -> causes bleeding)
should patients stop taking aspirin before dental surgery due to clotting effects
- controversial
- recommend continuing use to prevent emboli, myocardial infarction, or stroke
how long after taking aspirin does platelet inhibition become evident
- within 1 hour
what is the primary use of aspirin
- prevention of a first cardiovascular (eg heart attach) or cerebrovascular (eg stroke) event for most patients who are at moderate rose (use low-dose – 81 mg – aspirin daily)
what is the secondary use of aspirin
- low-dose aspirin to prevent cardiovascular or cerebrovascular events in patients with a history of heart conditions (eg stroke, engine, or acute coronary syndrome)
- reduction of pain, inflammation and fever
what are some contraindications of aspirin
- children less than 17 years of age (eye’s syndrome)
- nasal polyps and allergic rhinitis (hay fever/allergic reactions) to aspirin are at risk of developing bronchoconstriction and anaphylaxis)
- about 10% of patients with asthma are intolerant to aspirin and other NSAIDs
- ulcers
what are some adverse effects of aspirin
- GI upset (enteric coated tablets and buffered available)
- bleeding
- salicylism (toxicity)
- nausea/vomiting
- renal dysfunction
- doses stimulate the depth and rate of respiration
questions to ask patients that are taking aspirin
- ask patient why he or she is taking aspirin
- ask patient if his or her physician knows he or she is taking the aspirin
- ask patient if he or she is taking 81 mg or regular-strength aspirin (325 mg)
- determine if aspirin will cause increased bleeding during the dental procedure
- remind patient not to put aspirin directly on the tooth or gums
- consult patient’s physician regarding discontinuing use 7 days prior to dental surgery)
what does ASA do
- inhibits prostaglandin synthesis (pain and inflammation)
- mild to moderate relief of fever
- anticoagulant activity (do not give with other anticoagulants)
- reduce risk of colorectal cancer
- high doses -> GI discomfort and bleeding
- not to be given during 3rd trimester
what drugs interactions might we see with aspirin
- oral anti diabetic (increased hypoglycaemic response)
- angiotensin-converting enzyme (ACE) inhibitors (lowers effectiveness of the hypertensive drug)
- other aspirin-containing over the counter drugs (higher aspirin effects)
- thiazide or loop diuretics (lowers actions of diuretic)
- anticoagulants (increase bleeding)
- alcohol (increase GI irritation and bleeding)
- herbs (increased bleeding)
what do NSAIDs do
- block the COX enzymes and reduce prostaglandins throughout the body (also prevents platelet aggregation)
- ongoing inflammation, pain, and fever are reduced
- reduces protection of gastric mucosa (ulcers)
- NSAIDs differ in how strongly they inhibit COX-1 and thus their tendency to cause ulcers and bleeding
what are some indications of NSAIDs usage
- analgesia (dental pain)
- anti-inflammatory
- antipyretic
what are NSAIDs not used for
- the prevention of strokes and heart attacks
- all NSAIDs can lead to the onset of new or worsening of preexisting disease
- limit use of naproxen and other NSAIDs therapy to the lowest effective dose for the shortest possible duration to minimize risks (MI, bleeding)
what are some adverse effects and contraindications for use of NSAIDs
- GI effects: due to COX-1 inhibition -> decreases GI mucosal defense mechanisms and increases gastric acid secretion -> leads to ulceration. take with food
- kidney function: inhibition of prostaglandin synthesis -> depress kidney function
- asthma
- nasal polyps
- hypersensitivity to NSAIDs
what are some drug interactions we may see with NSAIDs
- angiotensin converting enzyme inhibitors (ACE inhibitors) and beta blockers (counteract the antihypertensive effects)
- lowers lithium levels
- increases bleeding with anticoagulants
- increases hypoglycaemic effects with oral anti diabetic drugs
directions for taking NSAIDs
- take the pill with a full glass of water and with food
- do not take with aspirin; can take with acetaminophen
what does naproxen do
- inhibit prostaglandin synthesis
- non selective inhibition of COX-1 and COX-2
what are some side effects of naproxen
- not serious
- GI upset (reduced if taken with food)
- dizziness
- drowsiness
- caution with patients with bleeding disorders because prolongs bleeding time
what is celebrex
- causes selective inhibition of COX-2
