Pharmacology Flashcards
Tapentadol (Nucynta)
Mu-opioid receptor agonist and SNRI properties.
50-100mg q 4-6 hours
Can give additional dose as soon as 1 hour after 1st dose if needed.
Less potent than morphine.
Methadone is better for this kind of pain than other opioids
Neuropathic or mixed nociceptive-neuropathic.
When titrating from one opioid to another due to unacceptable side effects, you should decrease the new dose:
25-50%
The increase opioid sensitivity seen when switching to a new opioid is called:
Incomplete-cross tolerance.
If you are switching a patient because their pain was not controlled on the previous opioid:
You can consider using the calculated dose of the new opioid.
In case of severe pain at the time of the switch:
You may have to increase the dose of the new drug from what it was converted to.
When a patient has the previous drug left in their body or a long acting drug:
Consider the remaining drug in the body and time the dosing of the new drug appropriately.
S/s of opioid toxicity
Constipation, nausea, sedation, itchiness, dizziness, confusion, hallucinations, vomiting, dry mouth, urinary retention, sweating, rash or hives.
Rectal morphine has a bioequivalence to oral morphine of:
1:1
Rectal hydromorphone has a ___ duration of action so its dosing is:
Longer; Q6H
Rectal drugs should not be administered to:
Patient who are dehydrated (insufficient fluid in the rectal vault), through ostomies, patients with diarrhea, colostomy, hemorrhoids, anal fissures or neutropenia.
Rectal drugs have a ___ amount of variability in absorption
high
Medications administered via IV are ____ percent bioavailable.
100%
Limit of SQ fluid:
2mL per injection or 1-2mL/hr with infusion.
Morphine Equianalgesia Parenteral to Oral
10:30
Oxycodone equianalgesia Parenteral to Oral
10:20
Oxymorphine equanalgesia Parenteral to Oral
1:10
What is the problem with Meperidine?
Short acting, repeat dosing causes metabolites that cause CNS excitation. Do not give with renal failure or elderly population.
Normal Cr/CL
100 mL/min
Better opioid drugs in renal failure
Hydromorphone, Oxymorphone, methadone, fentanyl.
How to treat acute severe pain in the opioid naive patient.
Morphine 1mg IV q minute for 10 minutes, followed by a 5 minutes respite and repeated until pain is controlled.
Subcutaneous morphine 2mg q 5 min or fentanyl 40mcg or hydromorphine 0.4 mg.
Oral 5mg PO IR Morphine or 1 mg hydromorphone or 5mg oxycodone ever thirty min until pain recedes.
What does controlled pain mean?
Initial 2-4 point drop in pain rating, not complete relief of pain.
Another guideline for opioid naive patients with moderate to severe pain:
1-5mg morphine IV and reassess at 15 min, then if needed, double the dose and reassess after 15 min for 2-3 cycles.
How to start ATC pain management
IR medication (Morphine) q 4 hours with same dose available for PRN 1-2 hours. Ask patient to keep pain diary. Increase opioid dose every 24 hours. Consider transitioning to oral sustained release.
Methadone time of onset
10-15 min.
How to deal with spontaneous pain
May be neuropathic. Give IR opioid as needed and consider co-analgesic.
The more lipid soluble an opioid is:
The quicker the onset of action.
Pharmacokinetic properities of morphine
Onset:30-40 min, Duration 4 hours
Pharmacokinetic properties of oxycodone
Onset: 30 min, Duration 4 hours
Pharmacokinetic properties of oxymorphone
30 min, 4-6 hours
Pharmacokinetic properties of hydromorphone
30 min, 4 hours
pharmacokinetic properties of methadone
10-15 min, 4-8 hours
pharmacokinetic properties of transmucosal fentanyl
5-10 min, 1-2 hours.
How do we dose rescue pain medication with long active opioids?
10-15% of TDD for rescue dose.
How do we dose rescue meds for IR drugs ATC?
25-50% of scheduled q4hour dose q 1-2 hours.
Rule of rescue dosing:
If less than 50 percent of the pain is relieved: double the dose.
If 50-100 percent of the pain is relieved: increase dose by half.
If close to 100% of the pain is relieved: no dose change.
Oral transmucosal fentanyl
Cannot be dosed by rules.
