Exam 5 Flashcards
How much Morphine is metabolized on the “first pass” through the liver?
75% It is much less potent when taken orally than when given IV/IM.
How soon after injection does Morphine exert its maximum effect? How long does a dose typically last?
Max effect = 1 hour Lasts 4-6 hours, longer in the elderly sometimes.
Half-life of Morphine
2-3 hours
What is Morphine metabolized to?
Conjugated to Glucuronide (in liver)
Excreted mostly in urine, some in feces.
Effects of Morphine on fetus?
Crosses placenta. Respiratory depression and possible drug dependence with chronic use.
What can opioids + MAO inhibiters cause? Which opioid in particular?
Hyperpyrexia (high fever) Meperidine (but can occur with all opioids)
What is a “Speedball”?
Opioid + Amphetamines or Cocaine
What are 3 types of drugs sometimes used in combination with opioids to enhance analgesic effect?
Aspirin/tylenol Antihistamines (hydroxyzine) Tricyclic antidepressants
Triad seen with Opioid poisoning
CNS depression (coma/stupor)
Respiratory depression
Miosis (pinpoint pupils)
Miosis can become mydriasis if the patient becomes severely hypoxic and is close to death
Treatments for Opioid toxicity
Supportive respiration
Naloxone
Aside from pain management, what are 4 other common uses for opioids?
Antitussives (codeine)
Antidiarrheals
Dyspnea associated with left heart failure/pulmonary edema (makes them feel better)
Abuse
Standard dose of Morphine
10 mg IV/IM, 10-30 orally
Morphine
Opioid used for severe pain Can be given IV/IM/SC or orally.
Used in many types of spinal anesthesia
3 new developments in Morphine usage
Infusion/autoinjector systems
PCA (patient controlled analgesia)
Spinal anesthesia
Codeine
Opioid used for mild-moderate pain and as an antitussive.
Much less potent opioid than morphine.
Taken orally 30-60 mg.
Sensitivity can vary considerably due to genetic differences.
Ultrarapid metabolizers can convert codeine to morphine much faster than most people, causing opioid intoxication.
Hydromorphone
Like Morphine, but more potent. Dilaudid
Oxycodone
Like morphine, but taken orally.
Often used in combo with tylenol
Usually used for mild-moderate pain.
Sustained release preparation used for severe chronic pain.
Hydrocodone
Similar to morphine/codeine.
Used orally to treat mild-moderate pain.
Antitussive.
Used to be schedule 3, now it’s schedule 2.
Zohydro ER is extended release prep that does not contain tylenol.
Meperidine
Weaker opioid compared to morphine. Taken orally or IV.
May have less of an effect on smooth muscle (less constipation/ urine retention).
Used for moderate-severe pain.
May cause less respiratory depression in newborn (used in OB)
Short acting, and chronic usage creates buildup of toxic metabolites that may cause seizures.
Heroin
More potent/euphoria inducing than Morphine. Schedule 1 in USA. Smoked/snorted/injected.
Methadone
Like morphine/heroin but less euphoric and longer acting (12-24 hours). Used to treat opioid addiction and pain.
Dosing is tricky and patient needs to be monitored.
It has a shorter duration when used as an analgesic (4-6 hours) than when used chronically to treat opioid dependence (12-24 hours).
Can only be dispensed for opioid dependence from licensed clinics.
Good analgesic for severe pain, but there is a stigma associated with it.
Fentanyl
Very potent mu agonist (100x morphine).
Used IV during anesthesia.
Also used as a transdermal patch for chronic pain management.
Fentanyl + droperidol
Induces neuroleptic analgesia.
Used for endoscopy/minor surgical procedures where the patient may not completely lose consciousness.
Opioid Combination Preparations
Opioid + aspirin or tylenol or ibuprofen.
If too much is taken, patient is at risk for toxicity of aspirin/tylenol/ibuprofen.