Fentanyl formulations Flashcards
What is pain?
pain is defined as an unpleasant sensory and emotional experience associated with actual of potential tissue damage?
What are the types of pain?
acute pain
- has an identified reason and is mild to severe
- starts suddenly and lasts for days to weeks
chronic pain
- cause is often not identified
- lasts for 3 months or more
breakthrough pain
- a sudden flare of pain that breaks through medication prescribed to control chronic pain
What are the different causes for cancer associated pain?
tumour pressing on organs, nerves or bones
bone fracture - metastatic spread in bones
poor blood circulation due to blocked blood vessels
organs blockage - bowel obstruction
side effects from chemotherapy, radiotherapy or surgery
How can the different stages of cancer associated pain be treated?
mild pain - non-opioid analgesics (NSAIDs) and adjuvant therapy (aspirin)
mild to moderate pain - opioids (fentanyl), non-opioid analgesics and adjuvant therapy
moderate to severe pain - strong opioids (long acting opioids) and short acting opioids +/- adjuvant therapy
What is breakthrough pain?
transitory exacerbation of pain with relatively stable and adequately controlled baseline pain
How can pain occur?
incident - pain that can be anticipated = occurring due to dressing change
spontaneous - pain that cannot be anticipated
Why can’t around the clock medication (ATC) be used to treat breakthrough pain?
ATC - e.g long acting opioid
long acting opioids ATC cannot used as
- it does not cover breakthrough pain completely
- over medication increases side effects
Why is fentanyl better for treating breakthrough pain?
has a more rapid onset and shorter duration of effect
- peak intensity of BTP is 3-5 min and lasts for 30 mins = requires fast acting treatment
opioid activity better coincides with the time profile of unpredictable episodes of BTP
What are the features of fentanyl?
is very potent - 80-100 times as potent as morphine
has a low molecular weight and is highly lipophilic
- is able to cross the blood brain barrier
undergoes extensive first pass metabolism so cannot be used orally
- is instead rapidly absorbed through mucosal tissues (transdermal patches)
- allows rapid onset of action and duration
How does durogesic work?
fentanyl transdermal patch
- drug passage through the skin into general circulation
= systemic effects
bypasses first pass metabolism
decreased dosing
can be self administered
has increased patient compliance
How long does durogesic take to work?
takes 12-16 hours to achieve therapeutic effect and 48 hours to reach steady state blood levels
is applied at 72 hour intervals
How have durogesic fentanyl patches been formulated?
has four layers and a protective peel strip to be removed before application
1 - polyester/ethylene backing layer is impermeable to drug and moisture
2 - fentanyl is contained in the drug reservoir
3 - has a polymer rate controlling membrane
4 - has a silicone adhesive layer which keeps the patch in situ for the 3 day dosing interval
How does Actiq work?
fentanyl lozenge with integral oromucosal application
- is placed inside the cheek and moved constantly up and down then changed to the other cheek in intervals
has
- large surface area
- is highly perfused
- high permeability
- rapid absorption and onset of action
How long does Actiq take to work?
-fentanyl lozenge
avoids first pass effect and allows easy and rapid dose titration
onset of action is 5-15 minutes and peak is 20-40 minutes
25% is absorbed via mucosal and the rest is absorbed in the GIT
- total bioavailability is about 50%
What is fentora? How does it work?
fentanyl buccal tablet
- dissolves rapidly with localised effervescent reaction
- transient shift in pH enhances the rate and extent of absorption across the buccal mucosa
