Painkiller Efficacy in 2010 Less Than in 2000

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This research shows efficacy of analgesics decreasing since 2000.

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“The evidence for pharmacological treatment of neuropathic pain” publication is a good meta-analysis of the current state of evidence-based treatment of neuropathic pain.

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I have quoted extensively from the article as it is important.

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“Abstract: One hundred and seventy-four studies were included, representing a 66% increase in published randomized, placebo-controlled trials in the last 5 years. Painful poly-neuropathy (most often due to diabetes) was examined in 69 studies, postherpetic neuralgia in 23, while peripheral nerve injury, central pain, HIV neuropathy, and trigeminal neuralgia were less often studied. Tricyclic antidepressants, serotonin noradrenaline reuptake inhibitors, the anticonvulsants gabapentin and pregabalin, and opioids are the drug classes for which there is the best evidence for a clinical relevant effect. Despite a 66% increase in published trials only a limited improvement of neuropathic pain treatment has been obtained. A large proportion of neuropathic pain patients are left with insufficient pain relief. This fact calls for other treatment options to target chronic neuropathic pain. Large-scale drug trials that aim to identify possible subgroups of patients who are likely to respond to specific drugs are needed to test the hypothesis that a mechanism-based classification may help improve treatment of the individual patients.”

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The black circles are recent circles, the light circles are from the past. Shift to the right means less effect.

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“Fig. 1. It shows the combined numbers needed to treat (NNT) values for various drug classes in all central and peripheral neuropathic pain conditions (not including trigeminal neuralgia). The figure illustrates the change from 2005 values in light grey to 2010 values in dark grey.  [emphasis mine]The circle sizes indicate the relative number of patients who received active treatment drugs in trials for which dichotomous data were available. Please note that the differences in study design and the patient populations preclude a direct comparison of NNT values across drug classes (see text). BTX-A: botulinum toxin type A; TCAs: tricyclic antidepressants; SNRIs: serotonin noradrenaline reuptake inhibitors; SSRIs: selective serotonin reuptake inhibitor.”

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“Fig. 2. It shows the combined numbers needed to treat (NNT) values for different drug classes against specific disease etiologies. The symbol sizes indicate the relative number of patients who received active treatment drugs in the trials for which dichotomous data were available.”

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 A disease-based classification: fact or fiction?

“Since (1) there are no clear indications that specific diseases should be treated with specific treatments, (2) symptoms and signs overlap in various neuropathic pain conditions [6], and (3) currently available drugs act with unspecific neurodepressant actions rather on pivotal pathophysiological mechanisms, at present there is no good rationale for a treatment algorithm that discriminates between underlying etiologies [45]. Nevertheless, the vast majority of trials have been done in painful diabetic neuropathy and PHN and few, if any, in certain other conditions (e.g. Guillain–Barré syndrome and small-fiber neuropathy), and recommending a treatment for other conditions may seem to be an unjustified jump.”

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“Supplementary Figure 1L’Abbé plot showing pain relief for all drugs for different neuropathic pain conditions. Each point illustrates one comparison against placebo (for trials listed in Supplementary Table 1). The axes indicate the percentage of patients with at least 50% pain relief with active and placebo treatment.© 2010 International Association for the Study of Pain”

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Conclusion

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“Pharmacological treatment still represents the main option for treating chronic neuropathic pain. Our understanding of neuropathic pain-generating mechanisms has grown considerably within the last few decades, but unfortunately this research has not been matched by a similar improvement in treatment efficacy. We are still limited in our efforts in managing neuropathic pain by relying on treating the symptoms of pain rather than identifying the underlying disease mechanisms causing the pain. Although 69 new randomized controlled trials have been published in the past 5years compared with 105 published trials published in the preceding 39years, only a marginal improvement in the treatment of the patients with neuropathic pain has been achieved.”

© 2010 International Association for the Study of Pain

The study is part of the European project, funded by the Innovative Medicines Initiative Joint Undertaking

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The material on this site is for informational purposes only,

and is not a substitute for medical advice, diagnosis or treatment provided by a qualified health care provider.

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For My Home Page, click here: 

Welcome to my Weblog on Pain Management!

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Subutex: Method for Tapering Off

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Method for tapering off the last 2 mg tablet of Subutex

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This step is very difficult.

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It has been a puzzle for physicians.

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Subutex is much stronger than most doctors understand. The FDA does not publish how strong it is compared to morphine because it is approved in the US only for opioid addiction, and potency is important only for pain control. But many pain specialists find subutex may control  pain far better than other opioid analgesics without the same side effects. Europe has approved Subutex for both pain and addiction.

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One milligram of Subutex is equal to 30 to 50 mg of morphine which means 2 mg Subutex equals 100 mg morphine. If it is important to take someone off all opioids, it is best to slowly taper off. Before proceeding to the use of Butrans patches, check the EKG. Prolongation of the QTc interval is listed as a warning for the patch, but curiously not for the much stronger tablet or film of the same buprenorphine.

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How to Taper

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1. Begin 3 Butrans patches and stop the daily 2 mg Subutex tablet (or 2 mg Subutex film).

Each Butrans patch delivers 0.5 milligram of buprenorphine, thus 3 Butrans patches = 1.5 mg/day. The patches last one week.

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2. Decide if you wish to reduce the dose every week or perhaps drop the dose every second or third week or six weeks, whatever you choose.

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3. When you drop the dose again, then apply only two Butrans patches every week before next change.

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4. Then one Butrans patch every week.

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Then stop all Butrans when ready.

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If the patient is using Butrans for control of substance abuse, that decision will need to be between their addictionologist and their psychologist or psychiatrist. Emotional stability and understanding of triggers for addiction must come first before making the important decision or relapse may occur.

 

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The material on this site is for informational purposes only,
and is not a substitute for medical advice, diagnosis or treatment provided by a qualified health care provider.
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For My Home Page, click here:  Welcome to my Weblog on Pain Management!
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Ketamine Intranasal for Rapid Relief of Pain and Depression

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Poorly managed pain can evolve into chronic disease of the nervous system

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Ketamine is an important analgesic, more important than opioids. It can dramatically reduce pain, and rapidly relieve depression and PTSD.  Please read my earlier posts here and here. And the NPR report here just after I posted this (skip to their last section). Yes, it is FDA approved and legal. One woman said:

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 ’It was almost immediate, the sense of calmness and relaxation.

‘No more fogginess. No more heaviness. I feel like I’m a clean slate right now. I want to go home and see friends or, you know, go to the grocery store and cook the family dinner.’

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NPR again reports ketamine’s rapid relief of depression. A 28 year old man whose refractory depression began at age 15, after ketamine, says:

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‘I Wanted To Live Life’

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Stephens himself has vivid memories of the day he got ketamine. It was a Monday morning and he woke up feeling really bad, he says. His mood was still dark when doctors put in an IV and delivered the drug.”Monday afternoon I felt like a completely different person,” he says. “I woke up Tuesday morning and I said, ‘Wow, there’s stuff I want to do today.’ And I woke up Wednesday morning and Thursday morning and I actually wanted to do things. I wanted to live life.”.
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Since then, they treated him with Riluzole that is FDA approved for ALS and has one of the dirtiest side effect profiles I have ever seen in medicine with serious organ toxicity. Ketamine rarely causes mild transient side effects, usually none. It appears the concern is how ketamine is used on the street with potential for abuse. I do not see ketamine abuse in my patients, some of whom are on opioids for pain or Valium family medicines from their psychiatrist. All of those have a greater potential for abuse, also not occurring in my patients. Pain and/or depression can lead to suicide.
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About 18 months ago, researchers at Yale found a possible explanation for ketamine’s effectiveness. It seems to affect the glutamate system in a way that causes brain cells to form new connections.
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Researchers have long suspected that stress and depression weaken some connections among brain cells. Ketamine appears to reverse the process.

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It would be of interest to see a case report of the bladder problems they mention. Is this in a single drug addict who used many unknown medications on the street? Several physicians have infused IV ketamine for persons with pain for many years, in far higher doses than I prescribe, with no report of any but transient minor symptoms.

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David Barsook’s 2009 review, reference below, describes changes that cause memory loss and brain atrophy with chronic pain, in particular, Complex Regional Pain Syndrome (CRPS), and they also occur with chronic depression:

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With the onset of chronic pain (including CRPS) a number of changes in brain function occur in the human brain including but not limited to: (1) central sensitization ; (2) functional plasticity in chronic pain and in CRPS; (3) gray matter volume loss in CRPS ; (4) chemical alterations; and (5) altered modulatory controls. Such changes are thought to be in part a result of excitatory amino acid release in chronic pain. Excitatory amino acids are present throughout the brain and are normally involved in neural transmission but may contribute to altered function with excessive release producing increased influx of calcium and potentially neural death.

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Brain atrophy and memory loss has also been shown in chronic low back pain as well as in chronic depression.

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Barriers to management of chronic pain are many:

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Although opioids are effective for acute pain, effective treatment of chronic pain is often daunting, particularly neuropathic pain.

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Opioids have been shown to create pain causing imbalance in the glial cytokines that favor pain rather than relief of pain. Opioids carry the risk of opioid-induced hyperalgesia which is a severe pain sensitivity. They affect the brain and endocrine system. Opioids may fail to offer significant relief, fail to improve function, and risk misuse, abuse, diversion and death. Their costs are astronomic, insurance coverage is increasingly limited, the potential for complications may be life threatening in a hectic medical setting, side effects can be lethal, lack of physician training in use of opioids and alternatives to pain control lead to increasing deaths, addiction and diversion. It has become a national emergency and a trillion dollar war on drugs.

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Complications can be greatly reduced through use of a scrupulous history and physical examination, but reimbursement is directly proportional to the shortest time spent with a patient. Will that help assessment and care?

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Individuals may have dramatically different responses to opioid therapy; some may not tolerate any, and relief must be balanced with side effects that increase as the dose increases. Patient status may change and require IV, rectal or tube delivery instead of oral formulas; drug-drug interactions may require rapid changes, and disease of kidney, liver or brain may require modifications or stopping altogether. They may increase risk of falls and cause central sleep apnea with drop in oxygen because the brain fails to give a signal to breathe.

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Chronic pain can lead to loss of sleep, hopelessness, depression, anger and other mood disorders such as panic, anxiety, hypochondriasis and post traumatic stress disorder [PTSD]. Treatment of mood disorders are shown to profoundly reduce pain perception and/or ability to cope with pain.

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Ketamine is anti-inflammatory and can reduce the need for opioid use, thus reducing the pain and side effects caused by opioids.

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Nasal ketamine is more effective than oral ketamine for pain relief; oral dosing has no effect on depression.

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Nasal delivery of ketamine is now possible due to advances in metered nasal sprayers that deliver a precise dose. No needle is required, no IV access, no travel to a specialist needed.

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You can carry pain relief with you and use it as directed when it is needed.

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Ketamine is an NMDA antagonist: it antagonizes the NMDA receptor which plays a profound role in pain systems and centralization of pain.

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Ketamine is neuroprotective and it can help other disease states  as noted by Barsook, 2009:

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Besides improvement in pain, “there may be lessons from other diseases that affect the brain; it is noteworthy that acute ketamine doses seem to reverse depression and ketamine decreased prevalence of post-traumatic stress disorder (PTSD) in soldiers receiving ketamine during their surgery for treatment of their burns. In addition ketamine attenuates post-operative cognitive dysfunction following cardiac surgery that has been known to produce significant changes in cognition. [emphasis mine] The data suggest that the drug can alter or prevent other conditions based on its NMDAR activity where other drugs NMDA receptor antagonists are perhaps not as effective in these or pain conditions. Lastly, NMDA antagonists have been used in degenerative disease (and pain may be considered a degenerative disease as defined by loss of gray matter volume, see above) with mixed effects perhaps relating to how they act on specific NMDA subtypes. Taken together, ketamine may act not only on sensory systems affecting pain intensity, but also on a constellation of brain regions that are involved in the pain phentype. [sic, phenotype]“

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Side Effects

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Ketamine is more frequently used in babies and children than in adults because high doses of ketamine can induce hallucinations in the adult. Importantly, it is used in high dose in adults for treatment of Complex Regional Pain Syndrome.

Low doses, cause little or no side effects in adults. If present, they are transient and often resolve in 20 minutes. Patient who respond to ketamine report good acceptance as they find the relief of pain and/or depression far outweighs any short term minimal discomfort.

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Pain care reform is urgently needed.

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Research funding for pain is less than half of one percent of the NIH budget. More research is needed, but research on low dose ketamine for treatment of pain and depression has gone on for twenty years.

The public health crisis of untreated pain, which often results in disability, parallels the country’s struggle to halt the cost of health care. The longer a person remains with untreated pain, the less likely they are to return to work or to be employable.

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Conclusion

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Pain control requires urgent attention. It is past time to put into practice the use of this valuable medication so people can get on with life instead of being mired in chronic pain that for many risks suicide and ensures continuing decades of disability. Academic studies are usually limited by defining a predetermined dose rather than clinically titrating to effect. Thus no surprise, they find no effect as every patient will have no response until they reach their dose. And that dose, in my experience, falls into a bell shaped curve. One size does not fit all. Some respond at very low dose, others require much more, and the majority fall between.

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In my experience prescribing ketamine for ten years, only a rare person has problems. Almost all find it has returned function or significantly relieved pain. Some have been able to entirely eliminate opioids that did nothing for their pain for decades, though they dutifully returned to the MD every month to chronicle that pain. Pain continued to be rated ten on a scale of ten; patient always compliant despite side effects of constipation and often depression. My patients find the benefits of nasal ketamine far outweigh the relief of oral ketamine and at much lower doses with fewer side effects.

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Further, while the pain relief may be short lived, some find it gets better with repeat dosing, and relief of depression may last one to two weeks with a single dose.

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References

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http://www.wjgnet.com/1007-9327/10/1028.asp  Ketamine suppresses intestinal NF-kappa B activation and proinflammatory cytokine in endotoxic rats.

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CONCLUSION: Ketamine can suppress endotoxin-induced production of proinflammatory cytokines such as TNF-a and IL-6 production in the intestine. This suppressive effect may act through inhibiting NF-kappa B.

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http://informahealthcare.com/doi/abs/10.1080/J354v16n03_03  Ketamine as an Analgesic Parenteral, Oral, Rectal, Subcutaneous, Transdermal and Intranasal Administration

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Ketamine is a parenteral anesthetic agent that provides analgesic activity at sub-anesthetic doses. It is an N-methyl-D-aspartate (NMDA) receptor antagonist with opioid receptor activity. Controlled studies and case reports on ketamine demonstrate efficacy in neuropathic and nociceptive pain. Because ketamine is a phencyclidine analogue, it has some of the psychological adverse effects found with that hallucinogen, especially in adults. Therefore, ketamine is not routinely used as an anesthetic in adult patients. It is a frequently used veterinary anesthetic, and is used more frequently in children than in adults. The psychotomimetic effects have prompted the DEA to classify ketamine as a Schedule III Controlled Substance. A review of the literature documents the analgesic use of ketamine by anesthesiologists and pain specialists in patients who have been refractory to standard analgesic medication regimens. Most reports demonstrate no or mild psychotomimetic effects when ketamine is dosed at sub-anesthetic doses. Patients who respond to ketamine tend to demonstrate dramatic pain relief that obviates the desire to stop treatment due to psychotomimetic effects (including hallucinations and extracorporeal experiences). Ketamine is approved by the FDA for intravenous and intramuscular administration. Use of this drug by the oral, intranasal, transdermal, rectal, and subcutaneous routes has been reported with analgesic efficacy in treating nociceptive and neuropathic pain.
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http://www.ncbi.nlm.nih.gov/pubmed/15109503  Safety and efficacy of intranasal ketamine for the treatment of breakthrough pain in patients with chronic pain: a randomized, double-blind, placebo-controlled, crossover study  Daniel Carr, et al, 2004
Crossover, 20 patients. Ketamine reduced breakthrough pain within 10min of dosing, lasting up to 60min
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http://www.ncbi.nlm.nih.gov/pubmed/15288418  Safety and efficacy of intranasal ketamine in a mixed population with chronic pain
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The intranasal route for ketamine administration has been applied only for pain of dressing changes in a single case study (Kulbe, 1998). In this patient, oxycodone and acetaminophen were ineffective to control pain during burn dressing changes in a 96-year-old woman cared for at home. She tolerated the burn dressing changes after three intranasal sprays of 0.1 ml each, in rapid succession, each containing 5 mg ketamine (15 mg total) (Kulbe, 1998).
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http://www.acutepainjournal.com/article/S1366-0071%2807%2900167-2/abstract  Safety and efficacy of intranasal ketamine for acute postoperative pain
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Ketamine delivered intranasally was well tolerated. Statistically significant analgesia, superior to placebo, was observed with the highest dose tested, 50 mg, over a 3 h period. Rapid onset of analgesia was reported (<10 min), and meaningful pain relief was achieved within 15 min of the 50 mg dose. The majority of adverse events were mild/weak and transient. No untoward effects were observed on vital signs, pulse oximetry, and nasal examination. At the doses tested, no significant dissociative effects were evident using the Side Effects Rating Scale for Dissociative Anaesthetics.
The safety profile following treatment with ketamine was comparable to that seen with placebo.
Although patients did report side effects of fatigue, dizziness and feelings of unreality more often following treatment with ketamine than following treatment with placebo, no patient reported hallucinations and the side effects were generally reported to be of mild or moderate severity, and transient. No serious adverse events were reported and the incidences of associated adverse events were comparable for ketamine and placebo. Although study medication was administered intranasally, nasal signs and symptoms were few and inconsequential. A distinctive taste, however, was reported more often following treatment with ketamine than following treatment with placebo.In conclusion this randomized, placebo-controlled, double-blind study, in 20 patients, has demonstrated that intranasal ketamine is safe and effective for BTP [breakthrough pain]. Our findings augment an early but promising literature documenting the effectiveness of nasal administration of a variety of opioids for pain management in adults (Dale et al., 2002) .
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~http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2875542/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2875542/  Ketamine and chronic pain – Going the distance, David Barsook, 2009

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This important paper covers essential points not mentioned by many, thus quoted at length below:

“Ketamine, brain function and therapeutic effect – neuroprotective or neurotoxic

With the onset of chronic pain (including CRPS) a number of changes in brain function occur in the human brain including but not limited to: (1) central sensitization ; (2) functional plasticity in chronic pain and in CRPS; (3) gray matter volume loss in CRPS ; (4) chemical alterations ; and (5) altered modulatory controls. Such changes are thought to be in part a result of excitatory amino acid release in chronic pain. Excitatory amino acids are present throughout the brain and are normally involved in neural transmission but may contribute to altered function with excessive release producing increased influx of calcium and potentially neural death. Here lies the conundrum the use of an agent that potentially deleteriously affect neurons that may already be compromised but may also have neuroprotective properties by mechanisms that include reducing phosphorylation of glutamate receptors resulting in decreased glutamatergic synaptic transmission and reduced potential excitotoxicity . Alternatively, ketamine may affect glia regulation of glutamate and inhibit glutamate release within glia. However, by whatever mechanism ketamine acts on CRPS pain, there does seem to be a dose/duration effect in that longer doses at levels tolerated by patients seem to prove more effective in terms of the duration of effects.

So what could be happening in the brain and what is required to alter brain systems and reverse the symptomatic state? Ketamine may diminish glutamate transmission and “resets” brain circuits, but it seems that a minimal dose and/or duration of treatment is required. Alternatively, ketamine may produce neurotoxicity and damage or produce a chemical lesion of affected neurons. These two issues are important to be understood in future trials. Reports from patients who have had anesthetic doses have included prolonged pain relief for many months. While the authors did not address issues such as the effect of dosing duration or repetitive dosing at say 6weeks, they did show a level of efficacy based on NNT that equals or betters most drug trials for this condition.”

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“Conclusions

As a community we have a major opportunity to define the efficacy and use of a drug that may offer more to CRPS (and perhaps other) patients than is currently available. This is clearly an opportunity that needs urgent attention and a number of questions remain to be answered. For example, is ketamine more effective in early stage disease? How does ketamine provide long-term effects? Further controlled trials evaluating dose, duration, anesthetic vs. non-anesthetic dosing are needed. Few of us really understand what it is like to suffer from a chronic pain condition such as CRPS. Ketamine therapy may be a way forward that can be brought into our clinical practice through further controlled studies that will allow for appropriate standards for use in patients.”

 

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The material on this site is for informational purposes only, and is not a substitute for medical advice,
diagnosis or treatment provided by a qualified health care provider.
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For My Home Page, click here:  Welcome to my Weblog on Pain Management!
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Opioids Create Pain via Molecular and Genetic Changes

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Chronic use of opioid pain medication

causes molecular and genetic changes that result in pain

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A brief update

American Pain Society May 2009 Symposia: Anti-analgesic Effects of Mu-opioids: Molecular and Genetic Mechanisms

The clinical benefits of opioid analgesics have not been fully realized due to substantial side effects, which include tolerance, dependence and opioid-induced hyperalgesia. Although the precise molecular mechanism of these phenomenon is not understood yet, it is generally thought to result from cellular excitatory effects of mu-opioids which contrast the major inhibitory effects.

Mark Hutchinson, PhD, discussed the new discovery that every clinically relevant class of opioid analgesics non-stereoselectively activates glial cells through TRL4 receptor. Activation of this receptor, primarily expressed by microglia, leads to the release of proinflammatory mediators that counter-regulate acute opioid analgesia.

How can opioid-induced glial activation oppose & augment different aspects of opioid action?

Opioid analgesia is opposed by opioid-induced spinal glial activation since increased neuronal excitability leads to elevated nociception. Increased brain opioid-induced glial activation also leads to increased neuronal excitability & within reward & dependence centers this is believed to increase opioid reward & dependence. Therefore analgesia is decreased & reward/dependence is increased.

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Counteracting hyperalgesia with naltrexone and dextromethorphan

In summary, Dr. Hutchinson describes the TRL4 receptor where opioids act to induce activation of microglia, releasing proinflammatory mediators that counteract analgesia and produce more pain.

Naltrexone, a mu opioid antagonist, has profound anti-inflammatory effects centrally on the microglia to produce analgesia.  This mechanism of action of low dose naltrexone is discussed here.

Dextromethorphan acts centrally on microglia by the same mechanism, producing analgesia.  Both naltrexone and dextromethorphan are classified as morphinans, morphine-like.·

More is less:  increasing the dose causes pain.

A steep road to climb, much less to understand.

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The material on this site is for informational purposes only, and

is not a substitute for medical advice, diagnosis or treatment provided by a qualified health care provider.

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For My Home Page, click here:  

Welcome to my Weblog on Pain Management!

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