Download Acute Pain Pharmacotherapy

Acute Pain Pharmacotherapy
Daniel Wermeling,
Pharm.D.
Professor
225 COP
Pharmacists Patient Care Process
Acute Pain Characteristics
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Indication or symptom of tissue damage and
the underlying cause of the pain should be
identified and treated.
Examples of Acute Pain
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Cholecystitis, 3rd molar impaction where pain is a
symptom of a medical problem
Post-surgical pain
Trauma
What are the signs and symptoms of acute
pain?
Typical Observations and
Information to Collect
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For the Event
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Nature of Injury &
Examination
Affective Distress
Vital Signs
Guarding at Site
PQRST
Demographics
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Additional
Information
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Medications
Pain meds in past
Medical history
Mental illness
Substance use
Allergy
Additional Factors to Consider
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Use of other CNS depressants can be
additive or multipliers – common postgeneral anesthesia
Concurrent medical problems, like COPD
Obesity – obstructive airway the patient can
not protect & Sleep apnea syndrome
Mental Illness
These may all be relevant to some patients
creating a riskier situation.
Patients with Other Chronic Problems
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Examine drug profile
Examine reasons for PK differences,
disease, renal, hepatic, age, etc.
Respiratory disorders
Psychiatric disorders
Neuromuscular disorders
Assessment
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Does the clinical picture make sense?
Are there risk factors that affect Plan?
Understand patient concerns and goals
Plan and Implement
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Plan in context of clinical setting such as ER,
PORR, Outpatient discharge, etc.
Individualized plan considering relevant data
and consider cost-effectiveness
Set goals of therapy and options
Educate patient on choices made
Make sure patient understands when to
come back for additional care
Monitoring and Evaluation
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In the setting context, is the plan working and
are goals being met?
Re-assess and document findings. What
were the outcomes?
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Is pain level clinically acceptable? Are there
adverse effects that are troublesome?
In collaboration, modify Plan if goals not met
Try again and re-assess
Pharmacologic
Treatment Options
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Follow Algorithm in DiPiro
Assess pain severity and follow options for
pain severity
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Mild – APAP/NSAIDs, ATC and BTP, Adjuvants
Moderate – Above in combination with Opioids
Severe – Opioids, ATC plus BTP, Dose Finding
Is relief adequate? Side Effect Issues?
Monitor and Reassess
Mild Pain & Non-opioid Analgesics
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Share many properties in relieving pain and are
pharmacologically similar
Differences are based on cost, pharmacokinetic
profile, side effects, onset, duration, etc.
Inadequate pain relief with one agent still warrants
trying other agent
Examples – ASA, APAP, NSAIDS
Give around the clock initially, not PRN
Rx dosing higher than OTC label dosing
Have a ceiling effect, dose increases = side effects
with no more efficacy
Characteristics to Consider in
Choosing Agents
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GI Irritation – ASA high, COX-2 lower
intensity
CNS effects – most are low
Hepatic toxicity – ASA and APAP have
greatest dose dependent risks
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Be careful with fixed combinations
Renal Toxicity – ASA, NSAIDS
Platelet inhibition with NSAIDs
Consider the common risks as applied to
your patient
Additional Features to Consider
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Depending on clinical situation
Tmax - Analgesic onset
Elimination half-life
Analgesic duration
Injectable – acetaminophen IV, ketorolac IM
& ibuprofen IV
Ketorolac nasal spray
Cost – COX-2 drugs expensive
Moderate Pain Therapy
First Line
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Add moderate potency opioid to drugs in the mild treatment
category
Synergy by acting through different mechanisms
Give round the clock, PRN for breakthrough pain
Examples
– Tylenol with Codeine
– Oxycodone or Hydrocodone with APAP or ibuprofen
– Meperidine no longer recommended
Second line therapies
– Tramadol/Tapentadol – weak opiate and NE/SE reuptake
inhibitor
– Mixed agonist/antagonist opioids – pentazocine,
butorphanol, etc.
Second Line Therapy Cautions
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Understand mechanisms and examine
concurrent medications
Can antagonize or exacerbate other therapy
Tramadol/Tapentadol with antidepressant
and opioids
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Serotonin syndrome
Mixed agonist-antagonists with opioids
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Potential antagonism of agonists
Severe Pain Management
Use of Potent Opioids
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Potent mu receptor agonists
Examples
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Morphine – prototypical
Hydromorphone
Oxymorphone
Fentanyl
Methadone
Differences in chemistry, PK, dosing, potency,
metabolite formation, active vs inactive metabolites
acute vs. chronic effects, etc.
Opioids—Drug Selection
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Choice of agent based on pain intensity,
pharmacologic factors, coexisting condition,
economic factors
Available forms: Tablet, liquid, sublingual,
rectal, transdermal, transmucosal, nasal,
parenteral, intra-spinal
Select the form most convenient and
comfortable for the patient
Oral ER/LA products not for Acute Pain
Opioids—Dosing
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Wide variation in effects in different patients
Dosage must be individualized
“Opioid-naïve” patients should usually start
with lower doses because of higher
susceptibility to adverse effects
Opioids—Titration
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Depending on the clinical setting repeated
dose adjustments may be necessary
Titrate upward until patients achieve relief or
experience intolerable adverse effects
Rate of titration depends on pain severity,
comorbid conditions and pain relief goals
Tolerance: With existing tolerance due to
chronic opioid use may require increased
dose or trial of another agent
Opioids—Dose Schedule
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In the setting:
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Should be designed to optimize analgesia and
patient convenience
Persistent pain: Around-the-clock dosing
Intermittent pain: Short-acting opioids
Break-through: Rescue doses of short-acting
agent for breakthrough pain
Opioids—Conversion
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Switching is done due to lack of efficacy, poor
tolerance, change in patient metabolic capacity
status, or formulary and reimbursement issues
Requires careful calculation of daily intake and
use of equi-analgesic dosage table
Be careful when changing routes of
administration, PO to IV and IV to PO, etc.
Use caution when calculating dose of new agent;
some recommend starting at 75% dosage
conversion and provide BTP doses
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Incomplete cross tolerance
See DiPrio for equi-analgesic dose comparisons
Minimizing Adverse Effects
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Titrate gradually
Determine cause of symptoms
Change dosing route or regimen
Switch to another opioid
Add an adjuvant and reduce dosage
Eliminate other nonessential agents
Assume that constipation will occur and provide
preemptive treatment
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Stimulant and stool softener
Drowsiness
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A dose and concentration related side effect
Tolerance develops over a few days
Care in driving, but once stable, can drive
fine. Care again when dose is changed.
Monitor closely after surgery – additive
effects of medication and leading toward
respiratory depression. Highest risk in first
24 hours post-operatively. Why?
Lower dose or change drugs if persistent
Hospital Monitoring
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Vital signs (BP,HR, RR) and the Ramsey
Scale
1 Anxious agitated restless
2 Cooperative, oriented and tranquil
3 Responds to vocal commands
4 Asleep, responds to voice or shaking
5 Asleep does not respond except pain
6 Unarousable
Respiratory Depression
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Respiratory depression is an extension of the CNS
depressant effects of opioids
Dose-dependent continuum of drowsiness to
lethargy to non-responsiveness, to decreased rate of
breathing and/or decreased tidal volume or depth of
breathing
Patient retains CO2, oxygen saturation drops
Respiratory failure and arrest are the final stages
CNS and Respiratory Depression
Monitoring in Hospital or PORR/ER
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Uncomplicated patients need vital signs, pain score
and Ramsey score
Observe rate and depth of breathing
Observe skin color
Higher risk patients
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Pulse oximeter monitor
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Records pulse and oxygen saturation of hemoglobin in the
blood
Alarms when abnormal parameters observed
A monitored bed in step-down unit or ICU
Respiratory Depression Treatment
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Actions follow the degree of depression
Respiratory rate 10-12
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Reduce dose of opioid medication
Monitor more frequently
Rate of 4-10
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Add supplemental oxygen
Stimulation – physical and verbal
Low-dose naloxone 40 mcg doses until respiratory rate
increases and patient is more responsive (Why this way?)
Temporarily stop opioid and then adjust down
Respiratory Failure - Apnea
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Full emergency measures
ABC – airway, breathing, circulation
Intubation, assisted ventilation, CPR
Naloxone 400 mcg IV bolus and repeat to
effect
Other supportive measures
Stop opioid; Patient will need pain medicine
at some point after recovery
Common Acute Pain Syndromes and
Their Management
Acute Low Back and Neck Pain
Low Back Pain Epidemiology/Etiology
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Second to the common cold the most common
affliction of mankind
80% of the world’s population has an episode
20% of the US population has an episode each
year
90% of LBP is of mechanical origin (muscle
strain, facet arthritis, stenosis)
Neck Pain Epidemiology/Etiology
Neck occurs about a quarter as often
as low back pain
 Frequency of events affecting the
world’s population is unknown
 10 - 15% of the US population has an
episode each year
 90% of neck pain is of mechanical
origin (muscle strain, whiplash, facet
arthritis)
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AHCPR Treatment Recommendations
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Acetaminophen and NSAIDs (ibuprofen, naproxen,
ASA) are effective for pain relief
Spinal manipulation (chiropractors, osteopaths,
physical therapists) are helpful at pain onset; reevaluation is required if pain continues for 4 weeks
Low-stress exercises (walking, swimming, biking)
should start 2 weeks after onset of mild to moderate
pain
Conditioning exercises for trunk muscles should start
after the first 2 weeks of symptoms
Clinical Use of Analgesics in Acute
Use/Surgical Situations
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Goals of pain assessment & treatment in
regard to procedures
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Decrease incidence and severity of patients’ post
surgery or trauma pain
Educate patients about their role to communicate
unrelieved pain
Enhance patient comfort & satisfaction
Reduce postoperative complications and in some
cases length of hospital stay
Pre-surgical Plans Include a Pain
History
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Significant prior experiences with pain
Previous methods for pain control and their outcome
Patient attitudes toward certain meds
Substance abuse
Fears – overmedication, side effects, “addiction”
Coping styles in dealing with stress & how patient
describes and shows pain
Family expectations about the experience
Pre-emptive or Preventative Analgesia
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Prevention is always better than treatment
whenever possible.
Patient outcomes are routinely better
Examples –
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Give analgesic prior to painful stimulus
Pre-procedure medications, local anesthesia,
general anesthesia
Site Specific Pain Management
Dental Surgery
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Prophylaxis is good – NSAIDS
Simple extractions – minor pain, local anesthesia
and then APAP or NSAIDS
Wisdom teeth extraction, bony impactions and
periodontal procedures – moderate pain
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Long acting local
“Moderate” pain analgesics like Tylenol#3, etc.
Neurosurgery
Craniotomy
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Need to monitor patients for abnormal
neurological signs
CNS active drugs for edema and seizures
used
Relative contraindication to use opioids
This procedures produces mild to moderate
pain and should respond to NSAIDS
Balance of bleeding disorder, antipyretic vs
CNS depressant
Abdominal and Thoracic Surgery
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Invasive procedures inducing severe pain
Aggressive treatment required
Combinations are useful
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Epidural/regional anesthetic blockade
Epidural or IV opioids and IV PCA
Use around the clock
Patient outcomes much better if pain control
is successful
Musculoskeletal Surgery
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Joint replacement (hip, knee, etc.) & spine
procedures tend to have moderate to severe pain
These patients may also be chronic pain patients
and using analgesics pre-op
There may be tolerance to opioids
Muscle spasms are common and muscle relaxants
needed
Caution: additive CNS depressant effects
Epidural and IV medications early on & convert to
orals
Epidurals can reduce additive CNS effects from
other medicaions by using local delivery
Trauma and Burns
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Minor fracture, long bones – oral or parenteral and convert to
oral
Severe injuries and pain
Concurrent CV instability
Titrate small IV doses of morphine to treat pain and prevent CV
instability
Severe pain is recurrent due to future manipulations and
procedures during days of recovery
Tolerance develops
Use short-acting benzodiazepines as adjuncts if fear and
anxiety are problematic, but must monitor closely for CNS and
respiratory depression
How to Handle Patients with
Current History of Licit or Illicit
Opioid Use
Mehta, Anesthesia, 2006
Audience Participation Minicases
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Face-lift operation
Total hip replacement
2nd degree sunburn
Wisdom teeth extraction (all four)
Three fingers crushed in stamp press
Sickle-cell crisis in IV drug abuser