Pain Management - Stueck Pharmacy Ltd.

Report
By Carla Alexander, 4th Year Pharmacy Student
March 15, 2011
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Pain management in the elderly differs from
that for younger people:
 Clinical manifestations are often complex and multifactorial
 Underreport pain
 Concurrent illnesses make pain evaluation and
treatment more difficult
 More likely to experience medication-related side
effects and have higher potential for complications
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However, despite these challenges, pain can usually
be effectively managed in this age group.
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Elderly may see an increased sensitivity to
analgesics
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Start low and go slow
Reassess pain scale frequently
Monitor side effects
Consider renal and hepatic function as well as
concurrent medications
Pain is dynamic
◦ Consider IR dosing as well as scheduled
◦ Treatment should be tailored to the level of pain
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Relaxation, refocus
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Physical Manipulation (physiotherapy)
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Thermal therapy (heating pad, ice packs)
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Physical Stimulation (massage)
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Behavioural (support groups)
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High alert medications
◦ Heightened risk of causing significant harm if used
in error
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Morphine and Hydromorphone (Dilaudid) are
the most frequent high alert medications to
cause patient harm.
◦ Dilaudid is 5x more potent than morphine
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Serious adverse events
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over-sedation, respiratory depression, seizures,
myoclonus, death.
Note: not to be used for neuropathic pain
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Step #1: Non-opioid such as acetaminophen, NSAID
Step#2: Opioid such as codeine, oxycodone, tramadol (in combination
with acetaminophen)
 Percocet (oxycodone + acet.)
 Tramacet (tramadol + acet.)
 T#2, T#3 (codeine + acet.)
Step#3: Opioid such as Morphine, oxycodone, hydromorphone,
fentanyl, methadone (used as monotherapy)
Note:
◦ Steps 1 and 2 have a ceiling dose due to the combination with non-opioids
(example: acetaminophen (4g/day)).
◦ Step 3 has no ceiling dose
◦ Must be on at least 60mg oral morphine equivalents for one week before
started on fentanyl.
◦ Adjunct treatment include: NSAIDS, antidepressants, anticonvulsants,
dexamethasone
Mild-to-Moderate Pain
Severe Pain
First Line
codeine or tramadol
morphine, oxycodone or
hydromorphone
Second Line
morphine, oxycodone or
hydromorphone
fentanyl
Third Line
methadone
Note: trial non-opioid options first (acetaminophen, NSAID)
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Immediate Release (IR)
◦ Duration 4-6 hrs
◦ Used for acute pain “breakthrough” pain or when
initiating someone on chronic therapy
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Sustained Release (SR)
◦ Usually lasts for 12 hrs
◦ Up to 72 hrs for fentanyl patches
◦ Unique once daily formulations
 Morphine, hydromorphone, tramadol
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More consistent pain relief
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More convenient for the patient
◦ Dosing OD or BID
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Do not crush, chew or dissolve SR products
◦ Can lead to rapid absorption of the entire 12-24hr
dose leading to sedation, respiratory depression
and potentially fatal dose.
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1/10th the potency of morphine
◦ 200mg po codeine = 20mg po morphine
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Increased risk of constipation & GI upset
Lower risk of overdose & addiction
Converted to morphine through CYP 2D6
metabolism in our body.
◦ Some people are rapid metabolizers, therefore increased
side effects because can convert faster
◦ Some people do not have CYP 2D6 therefore no
metabolism takes place, no morphine formed, no pain
relief.
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Combination products with non-opioids
◦ Acetaminophen (ex. T#1, #2, #3)- watch ceiling
dose of 4g/day of acetaminophen when dosing
 3g/day limit with elderly?
◦ Combination products also contain caffeine
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IR: tablets, syrup, injectable (IM)
SR: tablets, can be halved on score line but
patients must swallow half tablet intact
 Exception: 50mg tablet cannot be halved
 EDS criteria discussed later
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Lower risk of addiction & abuse
Increased risk of seizures and nausea
◦ Watch for patients with history of seizure or on
concurrent medications that lower seizure threshold
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Combination products
◦ Tramacet (tramadol 37.5mg + acet. 325mg) max 8 tabs/day
◦ IR: tablets- BID to QID
◦ SR: tablets- daily
◦ Note: none of the products are covered by SK Drug Plan
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2x more potent than morphine
◦ 10mg oxycodone po = 20mg morphine po
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Equianalgesia with chronic dosing
Used for mild to moderate pain when in
combination with non-opioid
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Used for severe pain when used as single agent
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Increased risk of abuse potential
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Combination products
(not on SK formulary)
◦ Percocet (acet. 325mg + oxycodone 5mg)
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IR: tablets, suppository
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SR: tablets (oxycontin)
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No parenteral formulation available
(not on SK formulary)
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Used as a standard for comparing potency
Available as:
◦ IR: tablets, solution, suppository, injectable
◦ SR: tablets, may be given rectally
◦ Unique SR: 24 hr coverage
 Kadian capsules- not interchangeable with other SR
products
 Should not be started in opioid naïve patients
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5x more potent than morphine
Available as:
◦ IR: tablet, liquid, suppository, injectable
◦ SR: capsule
◦ Unique SR: 24hr coverage
 Tablet
 Not listed in SK formulary
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Potency is variable
◦ The higher the dose of the original opioid, the more
potent the methadone is.
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Used for moderate to severe chronic pain as
well as opioid addiction
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Long acting and complicated dosing
◦ Duration of pain relief: initially 4-8 hrs, increases
to 24-48 hrs with repeated doses
◦ Takes 3-5 days to reach plasma steady state
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Peak respiratory depressant effects occur
later, and persist longer than its peak
analgesic effects
Risk of QT prolongation
Many drug interactions
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Available as:
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◦ Tablets, oral solution, powder (all which can be
administered rectally)
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Continue to be inappropriately prescribed,
dispensed and administered to opioid naïve
patients with acute pain.
Indicated for the management of persistent,
moderate to severe chronic pain that can not be
managed by other opioids.
Only to be used in patients:
◦ who require continuous around the clock opioid
analgesia for extended periods of time.
◦ who are already receiving opioid therapy at a total daily
dose of at least 60mg/day morphine equivalents for a
minimun of 7 days (no longer considered opioid naïve).
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100x more potent than morphine!
◦ 100mg po morphine/day = 25mcg fentanyl patch
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Available as
◦ Duragesic MAT and generic duragesic
 Required EDS for SK drug plan (later discussed)
◦ Parenteral solution (not on SK formulary)
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Less constipation, nausea, vomiting and
itchiness compared to morphine
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Very effective
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Convenient dosing schedule (every 72 hrs)
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No ceiling dose
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Opioid naïve patients
◦ Need to be on at least 60mg of morphine
equivalents per day for a week or longer before
initiating fentanyl patch.
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Acute pain management
◦ Takes 12-24hrs for analgesia to take effect
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Unstable or poorly controlled pain
◦ Pain controlled for at least 48 hrs
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Not appropriate for patients with:
◦ Fever- heat activated absorptive system
◦ Diaphoresis- difficult to adhere
◦ Cachexia- lipophilic drug, won’t absorb
◦ Morbid obesity- increased absorption, lose patch
◦ Ascites
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Continuous delivery of opioid for 72 hrs
◦ Breakthrough” doses may still be required
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Blood levels reach steady state between 1224 hrs
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Absorption is:
◦ 47% complete after 24hrs
◦ 88% complete after 48hrs
◦ 94% complete after 72hrs
 Therefore a used patch contains residual drug
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Apply patch to a non-hairy area on chest,
back, flank or upper arm
◦ Avoid areas of excessive movement
◦ If necessary, clip hair as close to skin as possible
◦ Do not shave as this irritates skin and increases
absorption
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If patch falls off, discard it and put a new patch
on at a different site.
If the gel contacts your skin, wash with water.
Do not use soap as it can increase the drug’s
ability to go through the skin
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Remove patch after 3 days
New patch should be applied to different site
Avoid sources of heat (hot tub, waterbeds,
electric blankets)
Disposal:
◦ Fold sticky sides together and flush down toilet or
discard in safe place (sharps container)
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Recommended to not cut as this will disrupt
the reservoir membrane and the entire dose
will be available immediately.
 Future: Duragesic-MAT patches may be cut, check with
pharmacy first!
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If only need ½ strength of patch use an
occlusive barrier to cover half.
Pain Medication
Elderly Dosing Considerations
Acetaminophen
Clcr 10-50ml/min: administer q6hrs; if Clcr
<10ml/min: administer q8hrs.
Ibuprofen
NSAIDS can compromise existing renal function
especially when Clcr is <30ml/min. Be aware of
comorbidities: GERD/PUD, GI bleed, Asthma, Renal
failure, Heart failure.
Codeine
Clcr 10-50ml/min: administer 75% of dose; if Clcr
<10ml/min: administer 50% of dose.
Tramadol
Elderly >65 yrs old use with caution and initiate at
the lower end of dosing range. Elderly >75 years
old, do not exceed 300mg/day for IR formulation and
use with great caution.
•IR formulation: Clcr <30ml/min: administer 50100mg dose q12rs (max 200mg/day).
•ER formulation: should not be used in patients with
Clcr<30ml/min because experience more adverse
effects: constipation, fatigue, weakness, postural
hypotension, dyspepsia.
Pain Medication
Elderly Dosing Considerations
Morphine
Clcr 10-50ml/min: administer 75% or normal dose;
if Clcr <10ml/min: administer 50% of normal dose.
Oxycodone
serum concentrations increase ~50% in patients with
Clcr <60ml/min, adjust dose based on clinical
situation.
Hydromorphone
Moderate renal impairment: start with a reduced
dose and monitor closely. Severe renal impairment:
consider use of an alternate analgesic with better
dosing flexibility.
Methadone
Clcr <10-ml/min: administer 50-75% of normal
dose. Because of its long half life and risk of
accumulation, methadone is difficult to titrate and is
not considered a drug of first choice.
Fentanyl
Elderly have been found to be twice as sensitive as
younger patients to the effects of Fentanyl. A wide
range of doses may be used. No renal adjustment
necessary.
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Potency varies by agent and route
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Oral/rectal doses ≠ parenteral doses
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(IM, SC, IV)
Parenteral route is 2x more potent than
oral/rectal route
 morphine 5mg po = morphine 2.5mg SC
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Onset 30-60mins
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Advantages:
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Preferred and easier to administer
Maintain patient independence
Portable
Less expensive
Disadvantages:
 Caution with patients suffering form vomiting,
difficulty swallowing or pain with swallowing
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IR formulations can be crushed
SR formulation CANNOT be crushed
◦ Open capsule and sprinkle contents onto small
amount of soft, cold food.
◦ Ensure patient does not chew the spheres
◦ Take within 30mins of sprinkling
◦ Mouth should be rinsed to ensure all medication
has been swallowed
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Or switch formulation/route/opioid
 Suppository, oral solution, injectable
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Onset varies depending on opioid
Use concentrated parenteral formulations
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Advantages:
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 Rapid onset of action
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Disadvantages:
 Maximum of 2ml
 Must retain volume in mouth for 10-15mins
 Not all meds have good transmuscosal absorption
(morphine)
 Thrush, mucositis & dry mouth may impact absorption
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Onset similar to oral
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Advantages:
 Used if unable to swallow pills
 Can administer controlled release oral opioids rectally
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Disadvantages:
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Not easy to administer
Patients feel uncomfortable
Limited commercial preparations
Avoid in patients with diarrhea, colostomy, hemorrhoids
Suppositories may be expelled before absorbed
High degree of inter-individual absorption variability
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Not recommended due to:
 Painful, unreliable absorption
 Nerve injury, sterile abscess formation and
muscle/soft tissue fibrosis with chronic injections
 30-60min lag time until peak effect
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Subcutaneous
Intravenous
Transdermal
Topical
Nebulized
Patient controlled analgesia (PCA)
Etc.
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Defn: transient pain not controlled by
around-the-clock analgesia
Use immediate release products
Used the same opioid for both scheduled and
prn, when possible
 Exception: fentanyl patch
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1. Idiopathic
 unpredictable, unknown cause
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2. End of dose failure
 pain at the end of a scheduled interval
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3. Incident pain
 Secondary to stimulus
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Nausea/vomiting
Constipation
 Laxative should always be used when on opioid
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Dizziness/orthostatic hypotension
Respiratory depression
Urinary Retention
 Improves within 1 week
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Delirium/confusion
 Usually resolves in 3-4 days
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Sedation
 Tolerance develops in 2-4 days
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Pruritis
Dry mouth
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Codeine, controlled release tablet, 50mg, 100mg, 150mg,
200mg
For treatment of :
(a) Palliative and chronic pain patients as an alternative to
ASA/codeine
combination products or acetaminophen/codeine combination
products.
(b) Palliative and chronic pain patients as an alternative to
regular release tablet when large doses are required.
In non-palliative patients, coverage will only be approved for a 6
month course of therapy, subject to review.
*Fentanyl Patch
For treatment of patients:
(a) Intolerant to, or unable to take, oral sustained-release strong
opioids.
(b) As an alternative to subcutaneous narcotic infusion therapy.
*These brands of products have been approved as
interchangeable.

Lecture Notes Pharmacy 557
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Saskatchewan Formulary
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RX Files
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Exceptional Drug Status Program
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American Geriatrics Society

Therapeutic Choices, 5th edition
Questions?

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