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Posts Tagged ‘Chronic pain’


Opioids, Pain, And Palliative Care [6.3.9]

Curator: Stephen J. Williams, Ph.D.

As written by Hrachya Nersesyan and Konstantin V Slavin in Current approach to cancer pain management: Availability and implications of different treatment options in Ther Clin Risk Manag. 2007 Jun; 3(3): 381–400

According to statistics published by the American Cancer Society in 2002, “50%–70% of people with cancer experience some degree of pain” (ACS 2002), which usually only intensifies as the disease progresses. Less than half get adequate relief of their pain, which negatively impacts their quality of life. The incidence of pain in advanced stages of invasive cancer approaches 80% and it is 90% in patients with metastases to osseous structures (Pharo and Zhou 2005).

Mediators of pain and inflammation are known to be secreted from tumor cells as well as infiltrating immune cells, activating and sensitizing primary afferent nociceptors (nociceptive pain) and damaging the nervous system (neuropathic pain). However, there has been difficulty in modeling cancer-induced pain in animals. This has hampered our understanding and therapeutic intervention of the clinical situation, especially concerning ovarian cancer patients.   It has been shown that 85% of ovarian cancer patients in palliative care (during last two months of life) still report severe pain although 54% of these women were given high intensity pain medications such as morphine, still the mainstream pain medication for severe cancer-associated pain. Admittedly, more research into the ability of cancer to provoke pain and sensitize the central nervous system, is warranted, as well as development of new methods of analgesia for cancer-associated pain at end-of-life. Therefore, in collaboration with several colleagues, in vivo models of nociceptive and neuropathic pain will be integrated with my co-developed in vivo tumor models of ovarian cancer. This tumor model allows for noninvasive monitoring of tumor burden without the need for anesthesia, as necessitated by imaging strategies to quantitate tumor burden, such as bioluminescence and MRI.

Even in an era of promising new cancer therapies, cancer pain is one of the highest concerns for the patient, their clinician, and surrounding loved ones, especially impacting quality of life during palliative care. Over half of cancer patients have reported severe pain in the course of their disease (List MA J Clin Oncol 2000 18:877-84) and the statistics are worse for ovarian cancer patients, regardless whether during treatment or in palliative care (see below review).

Journal of Pain and Symptom Management Volume 33, Issue 1 , Pages 24-31, January 2007

Pain Management in the Last Six Months of Life Among Women Who Died of Ovarian Cancer

Sharon J. Rolnick, PhD, MPH, Jody Jackson, RN, BSN, Winnie W. Nelson, PharmD, MS, Amy Butani, BA, Lisa J. Herrinton, PhD, Mark Hornbrook, PhD, Christine Neslund-Dudas, MA, Don J. Bachman, MS, Steven S. Coughlin, PhD

HealthPartners Research Foundation (S.J.R., J.J., A.B.), Minneapolis, Minnesota; Applied Health Outcomes (W.W.N.), Palm Harbor, Florida; Division of Research (L.J.H., D.J.B.), Kaiser Permanente Northern California, Oakland, California; Kaiser Permanente Center for Health Research (M.H.), Portland, Oregon; Josephine Ford Cancer Center (C.N.-D.), Henry Ford Health System, Detroit, Michigan; and National Center for Chronic Disease Prevention and Health Promotion (S.S.C.), Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Abstract Previous studies indicate that the symptoms of many dying cancer patients are undertreated and many suffer unnecessary pain. We obtained data retrospectively from three large health maintenance organizations, and examined the analgesic drug therapies received in the last six months of life by women who died of ovarian cancer between 1995 and 2000. Subjects were identified through cancer registries and administrative data. Outpatient medications used during the final six months of life were obtained from pharmacy databases. Pain information was obtained from medical charts. We categorized each medication based on the World Health Organization classification for pain management (mild, moderate, or intense). Of the 421 women, only 64 (15%) had no mention of pain in their charts. The use of medications typically prescribed for moderate to severe pain (“high intensity” drugs) increased as women approached death. At 5–6 months before death, 55% of women were either on no pain medication or medication generally used for mild pain; only 9% were using the highest intensity regimen. The percentage on the highest intensity regimen (drugs generally used for severe pain) increased to 22% at 3–4 months before death and 54% at 1–2 months. Older women (70 or older) were less likely to be prescribed the highest intensity medication than those under age 70 (44% vs. 70%, P<0.001). No differences were found in the use of the high intensity drugs by race, marital status, year of diagnosis, stage of disease, or comorbidity. Our finding that only 54% of women with pain were given high intensity medication near death indicates room for improvement in the care of ovarian cancer patients at the end of life.

Cancer pain is a complexity concerning not only the peripheral and central nervous systems but the cancer cell, the tumor microenvironment, and tumor infiltrating immune cells and inflammatory mediators. The goal of this article is to briefly introduce these factors governing pain in the cancer patient and a discussion of animal models of pain in relation to cancer.

Pain is considered as either termed nociceptive pain (activations and sensitization of primary afferent “nociceptor” neurons or neuropathic pain (damage to sensory nerves). Mediators of pain and inflammation are known to be secreted from tumor cells as well as infiltrating immune cells, activating and sensitizing primary afferent nociceptors (nociceptive pain) and damaging the nervous system (neuropathic pain).

For a great review please see Dr. Kara’s curation The Genetics of Pain: An Integrated Approach.

Palliative Care

For a good review please see the following LINK on Palliative Care

Palliative Care_4.6

Please See VIDEOs on Cancer, Pain and Palliative Care

https://youtu.be/88ri3VNOd2E

 

https://youtu.be/B1_Ui3f4AI4

https://youtu.be/-KOSinGapUg

From ACS Guideline: Developing a plan for pain control

The first step in developing a pain control plan is talking with your cancer care team about your pain. You need to be able to describe your pain to your family or friends, too. You may want to have your family or friends help you talk to your cancer care team about your pain, especially if you’re too tired or in too much pain to talk to them yourself.

Using a pain scale is a helpful way to describe how much pain you’re feeling. To use the Pain Intensity Scale shown here, try to assign a number from 0 to 10 to your pain level. If you have no pain, use a 0. As the numbers get higher, they stand for pain that’s getting worse. A 10 means the worst pain you can imagine.

0 1 2 3 4 5 6 7 8 9 10
No pain Worst pain

For instance, you could say, “Right now, my pain is a 7 on a scale of 0 to 10.”

You can use the rating scale to describe:

  • How bad your pain is at its worst
  • What your pain is like most of the time
  • How bad your pain is at its least
  • How your pain changes with treatment

Tell your cancer care team and your family or friends:

  • Where you feel pain
  • What it feels like – for instance, sharp, dull, throbbing, gnawing, burning, shooting, steady
  • How strong the pain is (using the 0 to 10 scale)
  • How long it lasts
  • What eases the pain
  • What makes the pain worse
  • How the pain affects your daily life
  • What medicines you’re taking for the pain and how much relief you get from them

NCCN Adult Cancer-Associated Pain Guidelines (see PDF)NCCN adult pain guidelines

NCCN gives a comprehensive guideline to Cancer Patient Pain Management for Caregivers, physicians, and educational materials for patients.

The attached PDF gives information on

  • Pain Definition and Pain Management Principles
  • Pain Screening, Rating and Assessment Guidelines
  • Management of Patients with Differing Opioid Tolerance
  • Opioid Titration Guidelines
  • Adjuvant Analgesia
  • Psychosocial Support

Table. Important Points in NCCN Guidelines for Pain Management

Pain Severity (pain scale level) guideline
All pain levels – Opioid maintenance, – psychosocial support, – caregiver education
Severe Pain (7-10) – Reevaluate opioid titration
Moderate (4-6) – Continue opioid titration

– Consider specific pain syndrome problem and consultation

– continue analgesic titration

Mild (0-3) Adjuvant analgesics

The clinical presentation of cancer pain depends on the histologic type of cancer, the location of the primary neoplasm, and location of metastases. (for example pain in breast cancer patients have different pain issues than patients with oral.cancer).

However, high grade serous ovarian cancer, the most clinically prevalent of this disease, usually presents as an ascitic carcinomatosis, spread throughout the peritoneum and mesothelium.

Ovarian cancer stem cells and mediators of pain

Although not totally accepted by the field, a discussion of ovarian cancer stem cells is warranted, especially in light of this discussion. Cancer stem cells are considered that subpopulation of cells in the bulk tumor exhibiting self-renewing capacity, generally resistant to chemotherapy, and therefore repopulate the tumor with new tumor cells. In this case, ovarian cancer stem cells could be more pertinent to the manifestations of pain than bulk tumor, as these cells would survive chemotherapy. This may be the case, as ovarian cancer pain may not be associated with overall tumor burden? Are there PAIN MEDIATORS secreted from ovarian cancer cells?

Some Known Pain Mediators Secreted from Ovarian Tumor Cells

Endothelin-1

Proteases and Protease-Activated Receptors

Hoogerwerf WA, Zou L, Shenoy M, Sun D, Micci MA, Lee-Hellmich H, Xiao SY, Winston JH, Pasricha PJ

J Neurosci. 2001 Nov 15; 21(22):9036-42.

Alier KA, Endicott JA, Stemkowski PL, Cenac N, Cellars L, Chapman K, Andrade-Gordon P, Vergnolle N, Smith PA.J Pharmacol Exp Ther. 2008 Jan; 324(1):224-33.

Bradykinin

Sevcik MA, Ghilardi JR, Halvorson KG, Lindsay TH, Kubota K, Mantyh PW

J Pain. 2005 Nov; 6(11):771-5

Nerve Growth Factor

Tumor Necrosis Factor

Opioids: A Reference

Opioid analgesics: analgesia without loss of consciousness

Three main uses of opioids

  1. Analgesia
  2. Antitussive
  3. Diarrhea

1954 – nalorphine, partial antagonists had analgesic effect. Morphine: Morpheus – Greek God of dreams

1) opiates: opium alkaloids including morphine, codeine, thebaine, papavarine

2) synthetic: meperedine, methadone

Chemistry

  • Antagonist properties associated with replacement of the methyl substituent on nitrogen atom with large group (naloxone and nalorphine replaced with allyl group)
  • Pharmacokinetic properties affected by C3 and C6 hydroxyl substitutions
  • CH3 at phenolic OH at C3 reduces first pass metabolism by glucoronidation THEREFORE codeine and oxycodeine have higher oral availability
  • Acetylation of both OH groups on morphine : heroin penetrates BBB : rapidly hydrolyzed to give monoacetylmorphine and morphine

Pharmaookinetics

  • Well absorbed from s.c., i.m., oral
  • Codeine and hydrocodeine higher absorption from oral:parental ratio because of extensive first pass metabolism
  • Most opioids are well absorbed orally but DECREASE potency due to first pass
  • Variable plasma protein binding
  • Brain distribution is actually low but opioids are very potent
  • Well distributed and may accumulate in skeletal muscle
  • Fentynyl (lipophilic) may accumulate in fat

 

Metabolism

  • Most opioids converted to polar metabolites so excreted by kidney ;IMPORTANT prolonged analgesia in patients with renal disease
  • Esters like meperidine and herion metabolized by tissue esterases
  • Glucoronidated morphine may have analgesic properties

 

Receptors

All three (mu, kappa, and delta) activate pertussis toxin sensitive G protein {Gi}

Opioids quiet pain (nociceptive) neurons by inhibiting nerve conduction (decrease entry of calcium or increase entry of potassium)

There are four major subtypes of opioid receptors:[12]

Receptor Subtypes Location[13][14] Function[13][14]
delta (δ)
DOR
OP1 (I)
δ1,[15] δ2
kappa (κ)
KOR
OP2 (I)
κ1, κ2, κ3
mu (μ)
MOR
OP3 (I)
μ1, μ2, μ3 μ1:

μ2:

μ3:

  • possible vasodilation
Nociceptin receptor
NOP
OP4
ORL1
  • anxiety
  • depression
  • appetite
  • development of tolerance to μ-opioid agonists

Tolerance and Physical Dependence

Tolerance: gradual loss of effectiveness over repeated doses

Physical Dependence: when tolerance develops continued administration of drug required to prevent physical withdrawal symptoms

  • With opioids see tolerance most with the analgesic, sedative, and antitussive effects; not so much with antidiarrheal effects

Major effects of opioids on Organ Systems

  • CNS
    1. Analgesia – raise threshhold for pain
    2. Euphoria – pleasant floating feeling but sometimes dysphoria (agitation)
    3. Sedation –drowsiness but no amnesia; more frequent in elderly than young but can disrupt normal REM sleep
    4. Respiratory depression – ALL opioids produce significant resp. depression by inhibiting the brain stem; careful in patients with impaired respiratory function like COPD or increased intracranial pressure
    5. Cough suppression – tolerance can develop; may increase airway secretions
    6. Miosis – constriction of pupils; seen with ALL agonists; treat with atropine
    7. Rigidity – mostly seen with fentanyl; treat with opioid antagonist like nalozone
    8. Emesis; naseua, vomiting

 

  • Peripheral
    1. Cardiovascular – no real major effects; some specific compounds may have effects on blood pressure
    2. GI – Constipation most common; loperamide (Immodium); pentazocine may cause less constipation; problem for treating cancer patients for pain; opioid receptors do exist in the GI tract but effect may be CNS as well as local
    3. Biliary system – minor, may cause constriction of bile duct
    4. GU (genitourinary) – reduced urine output by increased antidiuretic hormone
    5. Uterus – may prolong labor
    6. Neuroendocrine – opioid analgesics can stimulate release of ADH, prolactin
    7. Other – opioid analgesics may cause flushing and warming of skin; release of histamine?

 

Specific Agents

Strong Agonists

  1. Phenanthrenes –all are used for analgesia
  • Morphine
  • Hydromorphone
  • Oxymorphone
  • Heroin
  1. Phenylheptylamine
  • Methadone – longer acting than morphine; tolerance and physical dependency slower to develop than with morphine; low doses of methadone may be used for heroin addict undergoing withdrawal
  1. Phenyllpiperidines
  • Meperidine
  • Fentanyl (also sufentanil) which is 5-7 more times potent than fentanyl. Negative inotropic (contractile force) effects on heart
  1. Levorphanol

Mild to Moderate Agonist

  1. Phenanthrenes – most given in combo with NSAID
  • Codeine – antitussive, some analgesia
  • Oxycodone
  • Dihydrocodone
  • Hydrocodone
  1. Propoxyphene – Darvon, low abuse and low analgesia compared to morphine
  2. Phenylpiperidines
  • Diphenoxylate –used for diarrhea; not for analgesia and no abuse potential
  • Loperamide – antidiarrheal (Imodium), low abuse potential

Mixed Agonist-Antagonist & Partial Agonists

  1. Nalbulphine – strong kappa agonist and mu antagonist.. Analgesic
  2. Buprenorphine – analgesic. Partial mu agonist has long duration. Slow dissocation from receptor makes resistant to naloxone reversal
  3. Buterphanol – analgesia with sedation, kappa agonist
  4. Pentazocine – kappa agonist with weak mu antagonism.Is an irritant so do no inject s.c.

Antagonists

  1. Naloxone – quick reversal of opioid agonist action (1-2 hours); not well absorbed orally; pure antagonist so no effects by itself; no tolerance problems; opioid antidote
  2. Naltrexone – well absorbed orally can be used in maintenance therapy because of long duration of action

Antitussives

  1. Codeine
  2. Dextromethorphan
  3. Levoproposyphen
  4. Noscapine

Other posts related to Pain, Cancer, and Palliative Care on this Open Access Journal Include

Palliative Care_4.6

Requiem for Palliative Cardiology: The Voice of Dr. Esselstyn on Plant-Based Nutrition

Cancer and Nutrition

Thyme Oil Beats Ibuprofen for Pain Management.

Pain Management Drug Market: Insight Pharma Reports

New target for chronic pain treatment found

The Genetics of Pain: An Integrated Approach

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Curated by: Dr. V. S. Karra, Ph.D.

Pain is a major symptom in many medical conditions, and can significantly interfere with a person’s quality of life and general functioning.[1]. It is often caused by intense or damaging stimuli, such as stubbing a toe, burning a finger, putting alcohol on a cut, and bumping the “funny bone.”

English: Illustration of the pain pathway in R...

Pain is an absolutely unpleasant one. Knowing the time of onset, location, intensity, pattern of occurrence (continuous, intermittent, etc.), exacerbating and relieving factors, and quality (burning, sharp, etc.) of the pain will help the examining physician to accurately diagnose the problem. For example, chest pain described as extreme heaviness may indicate myocardial infarction, while chest pain described as tearing may indicate aortic dissection.

Acute pain is usually managed with medications such as analgesics and anesthetics. Management of chronic pain, however, is much more difficult and may require an interdisciplinary approach for treating or easing the suffering and improving the quality of life. Psychological factors such as social support, hypnotic suggestion, excitement, or distraction can significantly modulate pain’s intensity or unpleasantness.

The International Association for the Study of Pain (IASP) states that “Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”.[2].

Following is the IASP’s classification of pain:

(1) region of the body involved (e.g., abdomen, lower limbs),

(2) system whose dysfunction may be causing the pain (e.g., nervous, gastrointestinal),

(3) duration and pattern of occurrence,

(4) intensity and time since onset, and

(5) etiology

This system has been criticized by Clifford J. Woolf and others as inadequate for guiding research and treatment.

According to Woolf, there are three classes of pain :

Nociceptive pain: is caused by stimulation of peripheral nerve fibers and the stimulants could be Thermal, Mechanical and/ or Chemical. For example “heat or cold” (thermal), “crushing, tearing, etc.” (mechanical) and “iodine in a cut, chili powder in the eyes” (chemical).

Inflammatory pain: is associated with tissue damage and the infiltration of immune cells, and

Pathological pain: is a disease state caused by damage to the nervous system (neuropathic pain) or by its abnormal function (dysfunctional pain, like in fibromyalgia, irritable bowel syndrome, tension type headache, etc.).[3]

Pain will have a very detrimental effect on the quality of life. Experimental subjects challenged by acute pain and patients in chronic pain experience impairments in attention control, working memory, mental flexibility, problem solving, and information processing speed.[4]. Acute and chronic pain are also associated with increased depression, anxiety, fear, and anger.[5].

Patients who often have a background level of pain controlled by medications and whos pain periodically “breaks through” the medication is called breathrough pain and it is common in cancer patients . The characteristics of breakthrough cancer pain vary from person to person and according to the cause.

Harold Merskey said: “If I have matters right, the consequences of pain will include direct physical distress, unemployment, financial difficulties, marital disharmony, and difficulties in concentration and attention…”

Pain perception (point at which the stimulus begins to hurt) and tolerance thresholds (point at which the individual can’t tolerate the pain any more and when the subject acts to stop the pain) are not the same. The perception of pain is influenced by a multitude of variables including gender, age, mood, ethnicity and genetic factors [6],

Thus it is important to:

  • understand mechanisms of susceptibility to (chronic) pain,
  • Explore the genetics, emphasizing the conservation of pain-related genes, their functions and their advantages if any
  • Understand the role of gene polymorphisms in normal and pathological modulation of pain in models, humans, and as future drug targets
  • Explore the latest findings from human genome-wide investigation of genomic variability and gene expression on pain
  • Understand genetic and genomic techniques to study genetic contribution to (human) pain.
  • Study the progress of cutting-edge clinical trials and translate research findings to clinical practice
  • develop preventative approaches and novel treatment strategies

Advances in molecular, statistical and behavioral methodologies have suddenly allowed genetic investigations of complex biological phenomena, including pain. Genetic studies of pain are already showing their power to identify new molecular targets for drug development and create new animal models of pain pathology, says Jeffrey S. Mogil, PhD who is currently the E.P. Taylor Professor of Pain Studies and the Canada Research Chair in the Genetics of Pain and wrote a book on “The Genetics of Pain“.

Pain genetics can explain why we’re not all alike with respect to pain – why some people hurt more, and receive less benefit from existing analgesics. The knowledge gained holds the promise of allowing truly individualized pain therapy, says Mogil.

Algorithms for accessing and integrating available public data to examine disease-relevant mechanisms are of growing interest as publically available data sets grow at an ever-increasing rate. A meta-analysis of publicly available microarray data from rodents exposed to neuropathic or inflammatory pain was able to efficiently prioritize pain-related genes [7].

A similar approach using human gene expression data could be highly beneficial in generating data-driven hypotheses for pain genetics.

Most recent article, published on June 7, 2012, in open access journal  PLoS Computational Biology, on “Integrative Approach to Pain Genetics Identifies Pain Sensitivity Loci across Diseases” presented a novel integrative approach that combines publicly available molecular data and automatically extracted knowledge regarding pain contained in the literature to assist the discovery of novel pain genes. This study was approved by the Institutional Review Boards of Stanford University and SRI International.

In this meta-analysis, they took advantage of the vast amount of existing disease-related clinical literature and gene expression microarray data stored in large international repositories and

  • Ranked thousands of diseases according to the Figure shown below.

  • Obtained gene expression profiles of 121 of these human diseases from public sources.
  • Selected ‘genes with expression variation significantly correlated with DSPI across diseases’ as candidate pain genes.
  • Genotyped selected candidate pain genes in an independent human cohort, and finally
  • Evaluated for significant association between variants and measures of pain sensitivity.

In this study, the genes were chosen based on their high correlation with the DSPI and plausible biology as assessed by the available literature and human expression profile across tissue using The Scripps Research Institute BioGPS database [8].

The selected genes were:

  • ABLIM3 (actin binding LIM protein family, member 3),
  • PDE2A (phosphodiesterase 2A, cGMP-stimulated),
  • CREB1 (cAMP responsive element binding protein 1),
  • NAALAD2 (N-acetylated alpha-linked acidic dipeptidase 2), and
  • NCALD (neurocalcin delta).

These genes were selected from the candidate list and were prospectively tested for variants that may be associated with differential pain sensitivity in an independent human cohort.

ABLIM3 was selected as the top candidate as it showed the highest correlation with the DSPI. ABLIM3 is a newly characterized protein-coding gene. ABLIM3 is expressed in various tissues, most prominently in muscle and neuronal tissue [9], [10].

Polymorphisms in ABLIM3 (rs4512126) and NCALD (rs12548828, rs7826700, and rs1075791) showed significant association with the cold pressor pain threshold

The strongest signal was with rs4512126 (5q32, ABLIM3, P = 1.3×10−10)  for the sensitivity to cold pressor pain in males, but not in females – a sex-specific association.”

Significant associations were also observed with rs12548828, rs7826700 and rs1075791 on 8q22.2 within NCALD (P = 1.7×10−4, 1.8×10−4, and 2.2×10−4 respectively).

Authors said that, “This data-derived list of pain gene candidates enables additional focused and efficient biological studies validating additional candidates.”

Authors have demonstrated the utility of a novel paradigm that integrates publicly available disease-specific gene expression data with clinical data curated from MEDLINE to facilitate the discovery of pain-relevant genes. This approach was validated through a targeted genetic association study in an independent human cohort, where variants of selected pain gene candidates were evaluated for associations with experimental pain sensitivity measures in humans.

Authors hope that “the outlined approach can complement existing research efforts by assisting the formulation of data-driven hypotheses, and may serve as a template to discover genetic components of other clinically important phenotypes.

Further Reading:

Pain Gene Database (PGD)[11]

MeSH: Medical Subject Heading is a comprehensive vocabulary thesaurus organized in a hierarchical structure allowing the indexing of publications with various levels of specificity.

The 20 diseases with the highest disease-pain ratio from the DSPI are listed out of a total of 2962 diseases are

 .

Curated by: Dr. V. S. Karra, Ph.D.

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