Analgesics Flashcards
addiction
a chronic neurobiologic disease whose development is influenced by genetic, psychosocial, and environmental factors (same as psychological dependence)
acute pain
pain that is sudden in onset, usually subsides when treated, and typically occurs over less than a 6-week period
adjuvant analgesic drugs
drugs that are added for combined therapy with a primary drug and may have additive or independent analgesic properties, or both
agonist
a substance that binds to a receptor and causes a response
agonists-antagonists
substances that bind to a receptor and cause a partial response that is not as strong as that caused by an agonist (also known as a partial agonists)
analgesic ceiling effect
what occurs when a given pain drug no longer effectively controls a patient’s pain despite the administration of the highest safe dosages
analgesics
medications that relieve pain without causing loss of consciousness (sometimes referred to as painkillers)
antagonist
pain that occurs between doses of pain medication
breakthrough pain
pain that occurs between doses of pain medication
cancer pain
pain resulting from any of a variety of causes related to cancer and/or the metastasis of cancer
central pain
pain resulting from any disorder that causes central nervous system damage
chronic pain
persistent or recurring pain that is often difficult to treat; includes any pain lasting longer than 3 to 6 months, pain lasting longer than 1 month after healing of an acute injury, or pain that accompanies a non-healing tissue injury
deep pain
pain that occurs in tissues below skin level; opposite of superficial pain
gate theory
the most well-described theory of pain transmission and pain relief; it uses a gate model to explain how impulses from damaged tissues are sensed in the brain
narcotics
a term originally applied to drugs that produce insensibility or stupor, especially the opioids (e.g. morphine, heroin); currently used to refer to any medically used controlled substances and in legal settings to refer to any illicit or “street” drug
neuropathic pain
pain that results from a disturbance of function or pathologic change in a nerve
nociception
processing of pain signals in the brain that gives rise to the feelings of pain
nociceptors
a subclass of sensory nerves (A and C fibres) that transmit pain signals to the central nervous system from other body parts
non-opioid analgesics
analgesics that are not classified as opioids
non-steroidal antiinflammatory drugs (NSAIDs)
a large, chemically diverse group of drugs that are analgesics and also possess antiinflammatory and antipyretic activity but are not corticosteroids
opioid analgesics
synthetic drugs that bind to opiate receptors to relieve pain
opioid naive
describes patients who are receiving opioid analgesics for the first time and who therefore are not accustomed to their effects
opioid tolerance
a normal physiologic condition that results from long-term opioid use, in which larger doses of opioids are required to maintain the same level of analgesia and in which abrupt discontinuation of the drug results in withdrawal symptoms (same as physical dependence)
opioid tolerant
the opposite of opioid naïve; describes patients who have been receiving opioid analgesics (legally or otherwise) for a period of time (1 week or longer) and who are at greater risk of opioid withdrawal syndrome upon sudden discontinuation
opioid withdrawal
the signs and symptoms associated with abstinence from or withdrawal of an opioid analgesic when the body has become physically dependent on the substance
pain
an unpleasant sensory and emotional experience associated with actual or potential tissue damage
pain threshold
the level of a stimulus that results in the sensation of pain
pain tolerance
the amount of pain a patient can endure without it’s interfering with normal function
partial agonist
a drug that binds to a receptor and causes a response that is less than that caused by a full agonist (same as agonist-antagonist)
phantom pain
pain experienced in the area of a body part that has been surgically or traumatically removed
physical dependence
a condition in which a patient takes a drug over a period of time and unpleasant physical symptoms (withdrawal symptoms) occur if the drug is stopped abruptly or smaller doses are given; the physical adaption of the body to the presence of an opioid or other additive substance
psychologic dependence
a pattern of compulsive use of opioids or any other additive substance characterised by a continuous craving for the substance and the need to use it for effects other than pain relief (also called addiction)
referred pain
pain occurring in an area away from the organ of origin
somatic pain
pain that originates from skeletal muscles, ligaments, or joints
special pain situations
the general term for pain control situations that are complex and whose treatment typically involves multiple medications, various health car personnel, and non-pharmacologic therapeutic modalities (e.g. massage, chiropractic care, surgery)
superficial pain
pain that originates from the skin or mucous membranes; opposite of deep pain
synergistic effects
drug interactions in which the effect of a combination of two or more drugs with similar actions is greater than the sum of the individual effects of the same drugs given alone (e.g. 1 + 1 is greater than 2)
tolerance
the general term for a state in which repetitive exposure to a given drug, over time, induces changes in drug receptors that reduce the drug’s effects (same as physical dependence)
vascular pain
pain that results from pathology of the vascular or peri vascular tissues
visceral pain
pain that originates from organs or smooth muscles
World Health Organisation (WHO)
an international body of health care professionals, including clinicians and epidemiologists among many others, that studies and responds to health needs and trends worldwide
non-pharmacologic treatment options for pain
acupuncture, acupressure, comfort measures, counselling measures, distraction, hot or cold packs, hypnosis, massage, meditation, music therapy, physical therapy, relaxation, surgery, therapeutic baths, therapeutic communication, therapeutic touch, yoga
conditions that alter pain tolerance: lowered pain threshold
anger, anxiety, depression, discomfort, fear, isolation, chronic pain, sleeplessness, tiredness
conditions that alter pain tolerance: raised pain threshold
diversion, empathy, rest, sympathy, medications (analgesics, antianxiety drugs, antidepressants)
acute versus chronic pain: acute
onset: sudden (minutes to hours); usually sharp, localised; physiologic response (SNS: tachycardia, sweating, pallor, increased blood pressure)
duration: limited (has an end)
examples: myocardial infarction, appendicitis, dental procedures, kidney stones, surgical procedures
acute versus chronic pain: chronic
onset: slow (days to months); long duration; dull, persistent aching
duration: persistent or recurring (endless)
examples: arthritis, cancer, lower back pain, peripheral neuropathy
potential opioid adverse effects
constipation, nausea and vomiting, sedation and mental clouding, respiratory depression, subacute overdose
potential opioid adverse effects: constipation
opioids decrease gastrointestinal (GI) tract peristalsis due to CNS depression with subsequent constipation as an adverse effect; stool becomes excessively dehydrated because it remains in the GI tract longer
opioid adverse effects management: constipation
increased intake of fluids, stool softeners (e.g. docusate sodium), stimulants (e.g. bisacodyl or senna); agents (e.g. lactulose, sorbitol, and polyethylene glycol (Miralax); bulk-forming laxatives (e.g. psyllium) for which increased fluid intake is necessary to avoid fecal impactions or bowel obstructions
potential opioid adverse effects: nausea and vomiting
opioids decrease GI tract peristalsis and some stimulate the vomiting centre in the CNS
opioid adverse effects management: nausea and vomiting
antiemetics (e.g. phenothiazines)
potential opioid adverse effects: sedation and mental clouding
any change in mental status should be evaluated to ensure causes other than drug-related CNS depression are ruled out
opioid adverse effects management: sedation and mental clouding
persistent drug-related sedation may be managed with a decrease in the dosage of opioid or change in drug used; prescriber may also order various CNS stimulants
potential opioid adverse effects: respiratory depression
long-term opioid use is generally associated with tolerance to respiratory depression
opioid adverse effects management: respiratory depression
for severe respiratory depression, opioid antagonists (e.g. naloxone) may be used to improve respiratory status, and if they’re titrated in small amounts, the respiratory depression may be reversed without analgesia reversal
potential opioid adverse effects: subacute overdose
may progress slowly (over hours to days), with somnolence and respiratory depression
opioid adverse effects management: subacute overdose
often, holding one or two doses of an opioid analgesic is enough to judge if mental and respiratory depression is associated with the opioid; if improvement with this measure, opioid dosage is often decreased by 25%
potential opioid adverse effects: other
dry mouth, urinary retention, pruritis, myoclonus, dysphoria, euphoria, sleep disturbances, sexual dysfunction, and inappropriate secretion of antidiuretic hormone
opioid adverse effects management: other
ongoing assessment for each adverse effect so that appropriate measure can be implemented (e.g. sucking of sugar-free candy or use of artificial saliva drops or gum for dry mouth; use of diphenhydramine for pruritis)
opioid-induced adverse effects by body system: cardiovascular
hypotension, flushing, bradycardia
opioid-induced adverse effects by body system: central nervous
sedation, disorientation, euphoria, lightheadedness, dysphoria
opioid-induced adverse effects by body system: gastrointestinal
nausea, vomiting, constipation, biliary tract spasm
opioid-induced adverse effects by body system: genitourinary
urinary retention
opioid-induced adverse effects by body system: integumentary
itching, rash, wheal formation
opioid-induced adverse effects by body system: respiratory
respiratory depression, possible aggravation of asthma
opioid antagonists (reversal drugs): naloxone (IV) [Narcan]
raised or lowered blood pressure, dysrhythmias, pulmonary oedema, withdrawal
opioid antagonists (reversal drugs): naltrexone (PO) [ReVia]
nervousness, headache, nausea, vomiting, pulmonary oedema, withdrawal
analgesic drugs
acetaminophen, codeine sulfate, fentanyl, lidocaine (transdermal), meperidine hydrochloride, methadone hydrochloride, morphine sulfate, naloxone hydrochloride, naltrexone hydrochloride, oxycodone hydrochloride, tramadol hydrochloride
