Pain Medications Flashcards
Example of Nonopioids
Acetaminophen NSAIDS - Ibuprofen - Aspirin - Naproxen COX-2 Inhibitors -Celecoxib
This class of drugs contains Aspirin…..
Cyclooxygenase Inhibitors
Cyclooxygenase class of drugs is useful for…………
suppressing inflammation, relieving pain and reducing fever
Aspirin is special within the Cyclooxygenase class because it is the only drug that can protect against
Myocardial Infarction and Stroke
Effects of Cyclooxygenase drugs are primarily achieved through
inhibition of cyclooxygenase enzyme
What is the cyclooxygenase enzyme responsible for ?
Synthesis of Prostanoids (Prostaglandins and other related compounds)
Principal Adverse effects of Cyclooxygenase Inhibitors
Gastric ulceration, bleeding, renal impairment MI and stroke too (except for Aspirin)
COX
Cyclooxygenase
Two Forms of Cyclooxygenase
cyclooxygenase-1 (COX -1) and cyclooxygenase- 2 (COX -2)
COX-1 functions
found in practically all tissues where it mediates “housekeeping chores” protection of gastric mucosa supporting renal function promoting platelet aggregation
COX-2 functions
produced mainly at sites of tissue injury where it mediates inflammation and sensitizes receptors to painful stimuli present in the brain where it mediates fever and contributes to perception of pain present in kidneys where it supports renal function, blood vessels where it promotes renal dilation and the colon where it can contribute to colon cancer
Because COX-1 primarily mediates beneficial processes, it is labeled as the
“good COX”
Because COX-2 primarily mediates harmful processes, it is labeled as the
“bad COX”
Inhibition of COX-1 (good COX) largely has what kind of effects ?
harmful effects gastric erosion and ulceration bleeding tendencies renal impairment
Inhibition of COX-1 has one very beneficial effect - what is it ?
Think about Aspirin - it protects against MI and stroke, secondary to reduced platelet aggregation
Inhibition of COX 2 largely has what kind of effects
beneficial effects pain alleviation suppression of inflammation reduction of fever protection against colorectal cancer
Two adverse effects of COX-2 Inhibition
renal impairment promotion of MI and stroke
Two Categories of Cyclooxygenase Inhibitors
drugs that have anti inflammatory properties and drugs that lack anti inflammatory properties
NSAIDS are part of which Cyclooxygenase Inhibitor category?
Drugs that have anti inflammatory properties
NSAIDS include ………….
Aspirin, Ibuprofen [Advil, Motrin, others], naproxen [Aleve, others] Celecoxib (Celebrex)
Acetaminophen is part of which Cyclooxygenase inhibitor category ?
Those that lack anti inflammatory properties
Acetaminophen includes
Tylenol and others
Acetaminophen can reduce _____________ and ___________ but cannot suppress what ?
pain; fever It cannot suppress inflammation
NSAIDS can be divided into two groups which are
first generation NSAIDS and second generation NSAIDS `
First generation NSAIDS inhibit
COX-1 and COX-2
Second Generation NSAIDS inhibit
COX-2 only
Acetaminophen MOA
inhibits Cyclooxygenase , but not an anti inflammatory
Acetaminophen uses
reduces pain and fever
Acetaminophen Absorption
Rapid and nearly complete in the small intestine Depends on the rate of gastric emptying
Acetaminophen Distribution
Widely distributed in body fluids except fat 10-25% protein bound
Acetaminophen Metabolism & Excretion
Hepatic metabolism by cytochrome P450 enzyme. Renal excretion
Acetaminophen RN Considerations
Narrow therapeutic range. Reduced maximum dose now 3600mg/day. Beware of other meds that contain acetaminophen (e.g. Vicodin, Percocet, Darvocet, Lortab, etc.) Overdose: hepatotoxicity. Side Effects: Contraindications: liver failure, >2-3 alcoholic drinks a day
Ibuprofen MOA
Inhibit prostaglandins by blocking cyclooxygenase
Ibuprofen uses
Anti-inflammatory, anti-pyretic, analgesic
Ibuprofen Absorption
Primarily GI tract (80%) Tablets 120 minutes to peak serum concentration
Ibuprofen Distribution
90-99% protein bound
Ibuprofen Metabolism & Excretion
Hepatic metabolization by cytochrome P450 enzyme Excreted renally
Ibuprofen RN Considerations
Overdose: Side Effects: gastrointestinal bleed (GIB), inhibits platelet aggregation, renal dysfunction Contraindications: peptic ulcer disease and chronic kidney disease (CKD)
What are the endogenous opioid peptides found in the CNS and peripheral tissues ?
Endorphins, dynorphins, enkephalins. These play a role in the modulation phase of nociceptive pain. They block the pain signal’s pathway, thus decreasing the intensity of the pain
What are the three main classes of opioid receptors ?
Mu, Kappa, Delta receptors
Opioid analgesics act primarily by activating what kind of opioid receptors ?
Mu receptors
The activation of mu receptors causes ……………..
Activation of mu receptors causes analgesia, respiratory depression, euphoria, and sedation, constipation.
Mu receptors are also related to …………….
physical dependence
The activation of kappa receptors can also produce …………..
analgesia and sedation
Morphine is a ……………
opioid agonist
Morphine MOA
Works directly on the CNS by mimicking the actions of endogenous opioid peptides, primarily at mu and partly at kappa opioid receptors
Morphine uses
pain, cough, dyspnea
Morphine Absorption
30mg PO = 10mg IV PO, 50% bioavailable, plasma levels peak in 30 minutes IV, 100% bioavailable, plasma levels peak in 20 minutes 40% protein bound
Morphine Distribution
skeletal muscle, kidneys, liver, intestinal tract, lungs, spleen and brain. Morphine also crosses the placental membranes and has been found in breast milk.
Morphine Metabolism & Excretion
Liver, first pass effect Metabolites (morphine 3- and 6-glucouronides) can accumulate in renal failure and cause toxicity. Renal excretion 90%, biliary 10%
Morphine RN Considerations
Overdose: Respiratory Depression Anticipate constipation and treat preemptively
Non pharmacologic pain relief
Positioning: Immobilization Cutaneous stimulation: Heat Cold Massage Quiet Music therapy Distraction: Humor Relaxation using the patient’s own memory of peaceful events Eliciting the physiologic Relaxation Response
Barriers to Pain Management
Lack of education Importance of recognizing and addressing barriers Specific barriers: Inadequate assessment Cognition of client Fear of side effects Fear of addiction/tolerance Fear of respiratory depression Fear of hastening death Healthcare systems Cost and reimbursement
What is the WHO pain ladder
Guidelines based on pain ratings for the type and combination of analgesics administered
- *Pain Level 1-3/10**
- Non Opioid +/- adjuvant*
- *Pain Level 4-6/10**
Weak opioid for mild to moderate pain +/- nonopioid +/-adjuvant
Pain level 7-10/10
- Strong opioid for moderate to severe pain (morphine)*
- +/- non opioid +/- adjuvant*
