Objective 2.1 (1) Flashcards
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
A personal and individual experience
Whatever the patient says it is
Exists when the patient says it exists
pain
Level of stimulus needed to produce the perception of pain
A measure of the physiological response of the nervous system-therefore similar for most people
pain threshold
The psychological element of pain
The amount of pain a person can endure without it interfering with normal function
Varies from person to person
Subjective response to pain, not a physiological function
Varies by attitude, personality, environment, culture, ethnicity
pain tolerance
sudden, usually subsides when treated (postop pain)
acute pain
chronic or long-term pain, recurring lasts 3-6 months, and more difficult to treat
persistent pain
Pain results from stimulation of sensory nerve fibres called nociceptors.
These receptors transmit pain signals from various body regions to the spinal cord and brain
nociception
pain originating in skeletal muscles, ligaments or joints
somatic pain
pain originating from internal organs or smooth muscles
visceral pain
Medications that relieve pain without causing loss of consciousness
Commonly referred to as “Painkillers”
analgesics
moderate to severe pain
opioid analgesics
drugs from other chemical categories that are added to the opioid regimen
adjuvant analgesic drugs
what is the WHO 3-step analgesic ladder?
Step 1: Nonopioids with or without adjuvant medications after the pain has been identified and assessed. If pain persists or increases, treatment moves to:
Step 2: Opioids with or without nonopioids and with or without adjuvants. If pain persists or increases, management then rises to:
Step 3: Opioids indicated for moderate to severe pain, administered with or without nonopioids or adjuvant medications
Synthetic drugs that bind to the opiate receptors to relieve pain
Classified as both mild and strong agonists
opioid drugs
codeine, hydrocodone
mild agonists
morphine, hydromorphone hydrochloride, oxycodone, meperidine, fentanyl, methadone
strong agonists
not recommended for long-term use because of the accumulation of a neurotoxic metabolite, normeperidine, which can cause seizures
meperidine
drug reaches a maximum analgesic effect.
opioid ceiling effect
Bind to an opioid pain receptor in the brain
Cause an analgesic response (reduction of pain sensation)
agonists
Bind to a pain receptor
Cause a weaker pain response than full agonists
Also called partial agonists or mixed agonists
agonists-antagonists
Reverse the effects of these drugs on pain receptors
Bind to a pain receptor and exert no response
Also known as competitive antagonists
antagonists
what are opioids used for?
Mainly used to alleviate moderate to severe pain
Often first line agents analgesic in immediate post operative setting
Often given with adjuvant analgesic drugs to assist primary drugs with pain relief Balanced anaesthesia
Cough centre suppression
Treatment of diarrhea
what are the contraindications of opioids?
Known drug allergy
Severe asthma
Use with extreme caution in patients with the following:
Respiratory insufficiency
Elevated intracranial pressure
Morbid obesity or sleep apnea
Paralytic ileus (bowel paralysis)
Pregnancy
what are the interactions of opioids?
Alcohol
Antihistamines
Barbiturates
Benzodiazepines
Promethazine
Monoamine oxidase inhibitors (MAOI’s)-resp depression, seizures, hypotension
Others
what are the adverse effects of opioids?
Central nervous system (CNS) depression
Leads to respiratory depression
Most serious adverse effect
Nausea, vomiting, constipation, biliary tract spasm
Urinary retention
Hypotension, palpitations, flushing
Itching, rash, wheal formation due to histamine release (more with morphine, less with merperidine)
Pinpoint pupils indicating a possible overdose
A common physiological result of chronic opioid treatment
State of adaptation
Result: larger dose is required to maintain the same level of analgesia
opioid tolerance
Physiological adaptation of the body to the presence of an opioid
physical dependance