Analgesics Flashcards
Acute pain
Pain that usually starts relatively suddenly and has a specific cause or etiology. Generally doesn’t last more than about 3 months.
Chronic pain
Pain that persists beyond normal tissue healing time, which is assumed to be about 3 months. Pain signals remain active for weeks, months, or years.
Acetominiphen (Tylenol) is for ___
Mild to moderate pain
○ OTC, non-narcotic, non-NSAID
_____ is Commonly abbreviated APAP
Acetominophen (tylenol)
○ Acetyl-para-aminophenol (APAP)
○ Known as paracetamol outside the US
Acetominiphen MOA
Believed to cause inhibition of COX enzyme in various tissues, although it’s never been confirmed.
○ COX (cyclooxygenase) forms prostaglandins
● APAP may possibly inhibit prostaglandin E2 production in CNS
Where is acetominophen metabolized?
Metabolized in the liver – 90% by conjugation and 5% by CYP2E1 enzymes. 5%
excreted unchanged in the urine.
○ Toxic metabolites can accumulate in renal impairment.
Acetominophen Indications for use
Mild pain
Fever
Acetominophen Contraindications
● Severe active liver disease (IV)
● Severe hepatic impairment (IV)
In contrast to NSAIDs, ____ does not have antiplatelet or anti-inflammatory effects.
APAP
Black box warnings for Acetominophen
Hepatotoxicity
○ APAP has long been associated with acute liver failure, including cases of liver
transplant and death.
○ Generally seen with doses over 4000 mg per day.
Common side effects with acetaminophen
● Nausea
● Vomiting (IV use)
● Rash
● Headache
● Insomnia (IV use)
● Constipation (IV use)
● Agitation (peds IV use)
● Pruritus (peds IV use)
Adverse reactions with acetominophen
● Hepatotoxicity
● Acute renal tubular necrosis
Most commonly reported drug to Poison Control Centers in US
APAP (Acetominophen)
T/F There are no early symptoms that predict APAP toxicity
T
Risk for hepatotoxicity increases if presenting >____ hours after
24
If you suspect APAP overdose, ____ level is the most important diagnostic test (4+ hours after ingestion)
serum acetaminophen
Treatment of APAP OD is to _____
replenish Glutathione (GSH) by administering its precursor – N-acetylcysteine (NAC)
Toxic metabolite of APAP is reduced by natural antioxidant ______
Glutathione (GSH)
Max dose of acetominophen is ____ mg per day from all sources
4000
Three main neurotransmitters that Bind to and activate opioid receptors in the CNS
Endorphins, Enkephalins, Dynorphins
Activation of the CNS ______ results in efferent signals down into the
spinal cord, resulting in endogenous opioid release, blocking incoming pain signals
Analgesia System
Analgesia stystem structures
○ Periaqueductal gray – primary control center
○ Raphe nuclei neurons – extends down into spinal cord
○ Substantia gelatinosa – release endogenous opioids
____ is a natural occurring substance,
obtained from crude opium latex, extracted from the Opium Poppy
Morphine
____ is also found in crude opium along with morphine
Codeine
____ is a manufactured version of morphine
Heroin
____ is the prototype drug for strong Mu receptor agonists and all other opiates are compared to it.
Morphine
Opiates MOA
Bind to and stimulate the opioid receptors
○ Produce “morphine-like” effect
○ Mimic effects of endogenous opioids
All opioids stimulate ____ receptors to some degree
Mu
● Opioids are metabolized in _____
● Opioid metabolites are excreted by _____
liver (CYP3A4 or CYP2D6); kidneys
Opiate side effects
● Respiratory depression – dose dependent
● Sedation – due to decreased heart rate and respiratory rate
● Euphoria/Dysphoria – Possibly due to disinhibition of dopamine neurons
● Addiction
● Constipation – Can be severe
● Miosis – (pinpoint pupils) common
Opiate adverse reactions
● Respiratory depression and/or arrest
● Circulatory/cardiovascular depression
● Hypotension: Probably due to peripheral arterial and venous dilation
● Increased intracranial pressure
● Paralytic ileus
● Seizures (especially withdrawal)O
Opiate BBWs
● Appropriate use – ER formulations only when no good alternative for chronic pain
● Potential for drug addiction, abuse, and misuse.
● Medication error risk
● Life threatening respiratory depression can occur even with appropriate doses
● Neonatal withdrawal
● Avoid alcohol
● Risks of severe CNS depression with Benzodiazepines – Avoid combo!
Opiate follow up/monitoring
● Weigh risk/benefits in pregnancy
● Check baseline creatinine
● Monitor for respiratory depression with initiation and change in dose
Opiate contraindications
● Hypersensitivity to related drugs
● Respiratory depression
● Acute or severe asthma
● Paralytic Ileus
● GI obstruction or stricture
A _____ license is required in order to
prescribe narcotics, like opiate
medications
DEA
Codeine indications
Not usually prescribed by itself
○ Usually used in combo with another medication
■ Phenergan with Codeine, Tylenol #3, etc
Indications
● Moderate pain
● *Cough (Phenergan/codeine)
● Diarrhea (rarely anymore…just don’t, there are other options)
Codeine MOA
● Weak opioid receptor agonist that is actually a prodrug
○ Metabolized by CYP2D6 into Morphine
Unique codeine adverse reaction In addition to the common opioid reactions
○ Syncope
Contraindications for codeine In addition to the common opioid contraindications
○ Patients under 12 years, and 12-18 with respiratory disease
○ Post tonsillectomy or adenoidectomy in pediatric patients
BBWs for codeine In addition to the common opioid BBWs
Death related to ultra-rapid metabolism to Morphine.
Follow up and monitoring for codeine
● Weigh risks and benefits during pregnancy, especially for prolonged use; possible risk of birth defects based on conflicting human data
● Possibly unsafe with lactation – use alternative
● Check creatinine at baseline – cleared by kidneys
● Monitor signs and symptoms of respiratory depression, especially when initiating drug or increasing dose
Tramadol (Ultram) MOA
Tramadol has 2 mechanisms of action
○ Very weak Mu agonist
○ Blocks serotonin and norepinephrine reuptake (central analgesia)
Tramadol (Ultram) Indications
Moderate pain – Can be used in acute or chronic pain
Tramadol (Ultram) In addition to the common opioid side effects
○ CNS stimulation (with seizure
potential)
Contraindications for Tramadol (Ultram)
● Respiratory depression
● Acute alcohol/drug intoxication
● Suicide ideation or behavior
● History of addiction
Tramadol (Ultram) BBWs In addition to the common opioid BBWs
○ Risk of ultra-rapid metabolism of Tramadol – Respiratory depression and death have occurred in children who received Tramadol after a tonsillectomy and/or adenoidectomy
○ Great potential for CYP450-related drug-drug interactions
○ Profound sedation risk from concomitant use with Benzodiazepines
Adverse reactions of Tramadol (Ultram)
● Stevens-Johnson Syndrome (SJS)
● Toxic Epidermal Necrolysis (TEN)
● Suicidal ideation – Due to serotonin/NE mechanism
Follow up/monitoring for Tramadol (Ultram)
- Avoid during pregnancy
- Check creatinine at baseline
- monitor signs of respiratory depression
- Enquire of past Hx of seizures
Tapentadol (Nucynta) MOA
In addition to opioid agonism, it also inhibits reuptake of norepinephrine (central analgesia)
Tapentadol (Nucynta) indications
● Moderate to severe acute pain (regular tabs)
● Severe chronic pain (ER tabs)
● Severe diabetic neuropathic pain (ER tabs)
Tapentadol (Nucynta) Side effects
In addition to the common opioid side effects
○ Fatigue
○ Dyspepsia
○ Anxiety
○ Hot flashes