Polypharmacy Approach for Pain Management Tracy M. Hagemann, Pharm.D., FCCP, FPPAG October 5, 2012.
-
Upload
antonia-henderson -
Category
Documents
-
view
214 -
download
0
Transcript of Polypharmacy Approach for Pain Management Tracy M. Hagemann, Pharm.D., FCCP, FPPAG October 5, 2012.
Polypharmacy Approach for Pain Management
Tracy M. Hagemann, Pharm.D., FCCP,
FPPAG
October 5, 2012
Objectives
• Define polypharmacy as it relates to pain
management
• Identify patients at high risk for adverse
effects with polypharmacy
• Identify indications for the rational use of
polypharmacy in treating acute and chronic
pain
What is it?
Definition
polypharmacy /poly·phar·ma·cy/ (-fahr´mah-se)
• 1. administration of many drugs together.
• 2. administration of excessive medication.
– Duplication
– Potentially inappropriate medications
Dorland's Medical Dictionary for Health Consumers. © 2007
Polypharmacy and Pain
• Multiple medications to treat a single
condition
• Using multiple drugs from the same class or
multiple drugs with a similar mechanism of
action to treat different conditions
• Generally the RULE rather than the
exception, especially for chronic pain
When is it appropriate?
• Not all polypharmacy is inappropriate
– Co-morbidities
– Different mechanistic pathways
– Treatment of side effects
Who is at risk for adverse events?
• Those with co-morbidities
• Older patients
• Patients who are non-adherent to
their medication/treatment regimens
Rational Polypharmacy• Multimodal approach – achieve pain relief with
minimal toxicity
• Goals:
– Use lower doses of > 1 drug to minimize adverse effects
– Increase adherence
– Maintain analgesic efficacy to prevent pain
– Increase efficacy using > 2 drugs with different
mechanisms of action
– Target different but associated symptoms
– Target different locations of the disease process
Barriers to Rational Polypharmacy
• Drug-Drug Interactions
• Drug-Disease Interactions
• Medication abuse, misuse and
addiction
Pain Medication Arsenal• Non-opioids
• Opioids
• Adjuvants
– Anti-anxiety
– Anti-depressant
– Neuropathic pain treatments
• Anticonvulsants (i.e. gabapentin)
– Steroids
– Topicals
• Side effect management
– Constipation
– Nausea/vomiting
– Sedation
Considerations for Rational Polypharmacy
• Know drug toxicities
• Avoid overlapping/additive toxicities
• Know drug mechanisms of action
• Understand drug pharmacokinetics
• Have convincing evidence that the
combination is more effective than
monotherapy
Patient Factors
• Age
• Gender
• Ethnicity
Age
• Physiologic aging impacts pharmacokinetics
• Increased risk of drug-drug interactions with
multiple drug use
• Aging affects pharmacodynamics
– Affects at receptor sites
– Number of receptors binding capacity and
biochemical reactions
Age - Recommendations
• Initiate treatment at lowest effective
dose
• Give as small a dose as possible for
long-term therapeutic effect
• Make SLOW changes in medications
and doses
Gender
• Women use more medications
– 4.8 Rx meds vs. 3.8 Rx meds
– 81% vs. 74%
– 12% of women over 65 years of age
take at least 10 medications
• 23% take at least 5 prescription medications
Jorgensen et al 2001Linjakumpu et al 2002Kaufman et al 2002
Ethnicity
• Associations
– Ethnicity and other diseases like HTN, CV, malignancy
– Ethnicity and drug metabolism (CYP 2D6)
• 5-10% of Caucasians and 1-2% of African Americans and
Asians are poor metabolizers
– More likely to have frequent adverse events with standard doses
• Fast Metabolizers
– 10-15% Ethiopians and Saudi Arabians
– 1-5% Caucasians
– 2% African Americans
– 0-2% Asians
– More likely to have subtherapeutic effects with standard doses
Drug-Related Variables
• Mechanism of action/pharmacodynamics
• Efficacy
• Dosage forms available
• Pharmacokinetics
• Adverse effects
• Drug Interactions
• Cost
Indications and Examples
Indication #1
• To reduce drug intolerance by using a 2nd
drug that allows a lower dose of 1st drug
• May lead to increased adherence
• Provide analgesic efficacy at certain times
of day (giving IR with long-acting drugs)
– Control breakthrough pain in a patient taking
long-acting opioids
Indication #2
• To use a lower dose of a drug by
using a 2nd drug
– Example: opioid-sparing strategies,
addition of anti-inflammatories
Indication #3
• To address partial or non-response to 1 drug
by adding a 2nd drug to increase efficacy
– Example: use 2 medications with different
mechanisms of action
– Example: use a medication that has synergy
with the 1st medication
• Add an NMDA-type medication to a regimen
containing an opioid
Indication #4• To target different symptom clusters
that are a product of the disease or a
comorbid disease
– Example: pain associated with
depression
– Example: pain worsened by anxiety
Indication #5
• To treat the comorbid disease by
aggressively treating the index
disease
– Example: treat diabetes aggressively
thereby reducing peripheral neuropathy
severity
Indication #6
• To address different locations of the
disease process
– Example: pain that has peripheral AND
central mechanisms may require
medications that use each pathway
– Example: topical lidocaine patch with an
antidepressant
Indication #7
• To treat an adverse effect
– Nausea/vomiting
– Itching
– Sedation
– Constipation
Approach to Rational Polytherapy
• Consider:
– Pain and non-pain medications
– Prescription, OTC and homeopathies/others
– PK/PD profile of all used medications
– Therapeutic index of each medication
– Route of elimination of the medications
– Patient’s health status
5 Principles for Pain-Associated Comorbidity
• Use drugs for comorbid disease that have proven
analgesic efficacy
• Your 1st target symptom should always be PAIN
• Target all possible pain mechanisms
• Do not shoot for absolute pain relief
– Aim for tolerable pain levels (QoL)
• Use drugs to address more than one comorbidity
– Example: Sedating antidepressant for pain, sleep and
depression
Prescribing Guidelines for Polypharmacy
• Anticipate the impact of adding the
new medication
• Avoid
– Prescribing medications that
significantly inhibit or induce CYP450
enzymes
Prescribing Guidelines for Polypharmacy
• Prescribe medications that:
– Are eliminated through multiple
pathways
– Do not have serious consequences if
their metabolism is prolonged
–With different mechanisms of action
from the patient’s existing medications
Prescribing Guidelines for Polypharmacy
• Remind patients to tell you when other
physicians prescribe medications for them
• Remember
– Metabolism can create active or more active
compounds that the parent drug
– Generally, the older the medication, the less
is known about it’s metabolism
S.A.I.L.
• SIMPLIFY the drug regimen as much as possible
• Know the ADVERSE EFFECTS of each drug and
the drug-drug interactions
• Each medication should have a clear INDICATION
and well-developed therapeutic goal
• LIST the name and dosage of each medication in
the chart and provide this information to the
patient.
Selected References• Werder SF, Preskorn SH. Managing polypharmacy: walking the line between help and harm.
J Fam Prac 2003;2(2)
• Maggiore RJ, Gross CP, Hurria A. Polypharmacy in older adults with cancer. The Oncologist
2010;15:507-22.
• Chaparro LE, Wiffen PJ, Moore RA, Gilron I. Combination pharmacotherapy for the treatment
of neuropathic pain in adults. Cochrane Database 2012;7:Article #:CD008943
• Gallagher RM. Rational integration of pharmacologic, behavioral, and rehabilitation
strategies in the treatment of chronic pain. Am J Phys Med Rehabil 2005;84(3Suppl):S64-76.
• Al-Shahri MZ, Molina EH, Oneschuk D. Medication-focused approach to total pain: poor
symptom control, polypharmacy, and adverse reactions. Am J Hosp Palliat Care
2003;20:307-310.
• Smith H, Bruckenthal P. Implications of opioid analgesia for medically complicated patients.
Drugs Aging 2010;27(5):417-33.
• Pergolizzi JV, Labhsetwar SA, Puenpatom RA, et al. Exposure to potential CYP450
pharmacokinetic drug-drug interactions among osteoarthritis patients: incremental risk of
multiple prescription. Pain Practice 2011;11(4):325-36.