Study Suggests Chronic Pain is Widespread and Undertreated in MMT Programs By Guest Author Stewart B. Leavitt

shutterstock_119720380Pain is a worldwide epidemic and more than a third of all adults, or 100 million persons, in the U. S. alone suffer from chronic pain conditions of some sort, as estimated by the U.S. Institute of Medicine (IOM 2011). Even more troubling, newly published research suggests that the prevalence of clinically significant, persistent pain among patients in methadone maintenance treatment (MMT) programs is nearly twice that  of  the general population—and most of that chronic pain is going untreated.

Survey Provides Bleak Picture of Pain in MMT

Writing recently in the journal Pain Medicine, Kelly E. Dunn, PhD, and colleagues reported on a survey of MMT patients at the Johns Hopkins Bayview Medical Center in Baltimore, Maryland (Dunn et al. 2014). Approximately 80 percent of all patients at the clinic responded to a self-report questionnaire widely used in the pain field—the Brief Pain Inventory (BPI)—which assesses severity of pain and its interference with daily activities. Additional data were gathered on patient demographics, pain location, drug use, and current treatments for pain and addiction.

Overall, the 227 survey participants were 45 years old, had been in MMT for 4.5 years on average, and roughly half were male (47%) and Caucasian (49%). Sixty percent of respondents (N=137) indicated on the BPI that they had chronic pain. Also, there were some statistically significant differences in this group compared with MMT patients not reporting such pain: Patients with chronic pain were older (mean age 46 vs. 42 years, respectively), had higher average daily methadone doses (86 mg/d vs. 71 mg/d), and had a higher rate of benzodiazepine-positive urine samples in the past 90 days (7% vs. 3%).

Chronic pain was reported in multiple body areas by roughly a third (36%) of patients with pain, but the most common locations were the back (51%) and lower extremities (59%). Average pain during the past 24 hours on a 0-to-10 scale was reported as 5.8, with worst pain averaging 7.2. Also, using a 10-point scale to rate how pain affected daily life, interference with sleep was ranked highest (6.0 on average), followed by interference with general activity, normal work, and enjoyment of life. Interference in relationships with other people was least affected by chronic pain (rated 4.1 on average).

Merely 13 percent (N=18) of study participants with chronic pain reported receiving pain management treatment, and these patients were significantly more likely to be female, report less income from employment, and have a lower rate of benzodiazepine use. MMT patients being treated for pain most commonly reported back pain, and the majority of those being treated (89%) were prescribed medications; half received short-acting opioids and a third received nonopioid medications (eg., NSAIDs, gabapentin). Only 28 percent received nonpharmacologic therapies for their pain, such as physical therapy. Overall, those treatments were effective; study participants indicated that pain management provided, on average, 51 percent relief from their pain (range 0%-90%).

In sum, this study found that a substantial proportion of patients in a large MMT program reported clinically significant and persistent pain, for which only a relative handful were receiving pain management therapy. Dunn and her coauthors state, “Overall these data suggest that pain was not being adequately evaluated or treated in the majority of this sample. These findings are remarkable . . . and they illustrate what little progress has been made in the past 10 years regarding the concurrent treatment of pain and opioid use disorders.

Better and More Research is Needed

Similar to Dunn et al., in 2008, Cruciani and colleagues reported a study that found 61 percent of 390 MMT patients had experienced persistent pain for more than 6 months, and greater than a third of those patients (37%) had severe chronic pain (Cruciani et al. 2008). In an Addiction Treatment Forum interview article last year (see AT Forum, Winter 2013), it was noted that pain in patients attending MMT programs is commonplace, and a recent study of 489 patients had found that 237 (48.5%) had clinically significant chronic pain. Generally, past research surveys have reported high but varying prevalences of chronic pain among MMT patients, ranging from approximately 27 percent to 80 percent, with relatively few receiving pain care (references in Dunn et al. 2014).

While the newly reported study by Dunn and colleagues is consistent with most of the past research, it also exhibits many of the limitations in this area of scientific inquiry:

  • Dunn et al. gathered data for their study between December 2006 and January 2007, but were just reporting on results now in 2014; so, the outcomes may or may not reflect current circumstances. Unfortunately, it is not unusual in the pain research literature or government surveys for the reporting of data to come long after its collection.
  • Chronic pain was defined in the Dunn et al. study as answering “yes” to the BPI question, “Have you had pain other than everyday kinds of pain today?” And, even though locations of pain also were reported by patients and recorded by the investigators, this was a somewhat vague definition of chronic pain.This is a common problem encountered in most surveys of chronic pain, since there usually are no readily observable clinical signs or imaging evidence (eg., on X-ray, MRI) of pathology to confirm the presence, severity, or duration of pain. Pain most often is what the patient says it is, without sufficient clinical confirmation; so, it is understandable that there are wide variations in the prevalence of pain reported in different studies of pain in MMT patients, as well as in the general population.
  • There was a small, but significant, increase in benzodiazepine use among patients with pain (small differences between groups in illicit opioid and cocaine use were not statistically significant). However, considering that sleep disturbance was ranked high in persons with pain, this might account for their greater use of sedatives like benzodiazepines; additionally, Dunn et al. did not distinguish between prescribed vs. illicit use of these medications.
  • There was no assessment by Dunn et al. of which came first, pain or addiction, patients’ histories of pain or its treatment, and how MMT might have affected chronic pain. For example, although patients with pain were receiving higher average methadone doses (86 mg/day), the researchers acknowledge that persistent symptoms of opioid withdrawal in some persons were likely confused with chronic pain. Dunn and coauthors also note that some patients might have been receiving certain treatments in the MMT clinic—eg., antidepressants, cognitive behavioral therapy, biofeedback—that were intended for pain management, but not identified as such.
  • In general, the study by Dunn and colleagues surveyed a relatively small sampling of MMT patients in a single clinic setting, which cannot be assumed to represent the larger MMT population. While they present statistical data on those patients receiving pain care during MMT, their numbers were so small (N=18) that the validity of results in this group need confirmation in a larger sampling. For example, the findings that patients receiving pain care were more likely to be women, making less money from employment, and less likely to be using benzodiazepines should be cautiously considered in view of such small numbers.

Dunn et al. do not speculate as to why there is such a high prevalence of chronic pain among MMT patients, or why so few patients receive pain management for those conditions. Clearly, more and better research is needed to understand these problems and to develop strategies for providing effective pain management in the presence of the disease of addiction. At the least, there is a need for prospective studies examining large numbers of patients upon entry to MMT—or buprenorphine therapy—for addiction and during long-term follow-up to determine the progress of those with clinically diagnosed pain conditions.

Challenges and Opportunities

As Dunn and colleagues point out, patients with opioid addiction are likely being “systematically undertreated for pain.” And, while surveys have found that MMT clinic staff are interested in receiving education on treating pain in persons with substance-use disorders, there could be important barriers for MMT patients when it comes to receiving adequate pain care.

Opioid analgesics have been demonstrated as effective for relieving most types of moderate to severe pain, although their long-term use for chronic pain needs further investigation. Dunn and colleagues found that half of their respondents being treated for pain (N=9) were administered short-acting opioids, and Cruciani et al. similarly had noted that 47 percent of MMT patients with pain in their survey were receiving opioid pain relievers. Methadone itself is an excellent analgesic; however, to be effective for pain, it requires more frequent administration than the once-daily (or even split-dose) regimen provided during MMT for addiction. At the same time, many staff in MMT programs are uneducated in, or uncomfortable with, the concurrent administration of methadone and other opioids.

Often multiple types of pain treatment are necessary—spanning the medication and nondrug spectrums—which can be costly and required for extended periods of time. Yet, Dunn and her coauthors note, patients in addiction treatment have historically had limited access to insurance or other financial resources for such care. Furthermore, the pain-care field is highly fragmented, with the various specialists—eg., rheumatologists, orthopedists, neurologists, physiatrists—in high demand and short supply in most communities.

Dunn et al. conclude that their study should illustrate to health care professionals in both the substance abuse treatment and pain management fields that “patients with both disorders are not necessarily intractable hopeless cases and that they deserve the same level of attention and clinical care as chronic pain patients in the general population.” However, unless the many challenges are overcome, the plights of persons with chronic pain in methadone or buprenorphine maintenance treatment are unlikely to improve. There is an important opportunity here for the addiction treatment and pain care fields to forge alliances that can serve the mutual goal of achieving better care for patients with co-occurring pain and opioid use disorders.

References

Cruciani RA, Esteban S, Seewald RM, et al. MMTP patients with chronic pain switching to pain management clinics. A problem or an acceptable practice? Pain Med. 2008;9(3):359-364. doi: 10.1111/j.1526-4637.2006.00224.x. http://www.ncbi.nlm.nih.gov/pubmed/18366514

Dunn KE, Brooner RK, Clark MR. Severity and interference of chronic pain in methadone-maintained outpatients [Epub ahead of print April 7, 2014]. Pain Med. doi:10.1111/pme.12430. http://www.ncbi.nlm.nih.gov/pubmed/24703517

IOM (U.S. Institute of Medicine). Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research. June 2011. http://www.iom.edu/Reports/2011/Relieving-Pain-in-America-A-Blueprint-for-Transforming-Prevention-Care-Education-Research.aspx.

————————————————————————————
Stewart B. Leavitt, MA, PhD, is a former editor of Addiction Treatment Forum and most recently was director/editor of Pain Treatment Topics.

Conferences/Meetings

events1American Mental Health Counselors Association (AMHCA) Annual Conference
July 10-12, 2014
Seattle, Washington
Contact: http://www.amhca.org/

 

National Association for Court Management (NACM) 2014 Annual Conference
July 13-17, 2014
Scottsdale, Arizona
Contact: http://www.nacmnet.org/conferences/index.html

 

Virginia Summer Institute for Addiction Studies
July 14-16, 2014
Williamsburg, Virginia
Contact: http://www.vsias.org/

 

C.O.R.E. (Clinical Overview of the Recovery Experience 2014 Conference
July 20-23, 2014
Amelia Island, Florida
Contact: http://core-conference.com/

 

Community Anti-Drug Coalitions of America (CADCA) Mid-Year Training Institute
July 20-24, 2014
Orlando, Florida
Contact: http://www.cadca.org/trainingevents/conference-event

 

National Association of Social Workers (NASW) 2014 Conference
July 23-26, 2014
Washington DC
Contact: http://www.socialworkers.org/

News & Updates – May 29, 2014; Issue 201

The Hidden Dangers of Benzodiazepines (Infographic)

benzos 5-28-14“In the last year there have been several studies/stories about the risks associated with benzodiazepine abuse.  And while benzodiazepines have been prescribed for decades to treat anxiety and seizure disorders, the possible threat of overusing them is real and with that comes dependency, overdose and the potentiality of death.  Did you know that since 2010, there have been 6,507 US drug overdose deaths that involved benzodiazepines?  Because of this rising number, Foundations Recovery Networkcreated an infographic to help familiarize those about benzodiazepines but most importantly help create awareness regarding the possible addiction with benzodiazepines.”

Broken down in sections, the infographic (http://www.dualdiagnosis.org/benzodiazepine-addiction/) goes into detail about:

  • What are benzodiazepines: their brand names and the amount of prescriptions filled in the US in 2011, the number of related ER visits in 2010 and the confiscations by law enforcement for each associated drug.
  • Why prescribe benzodiazepines, specifically the disorders that are treated
  • Common side effects and contraindications with benzodiazepine use
  • Key statistics related to the dangers of abuse
  • Symptoms of overdose

Source: Foundations Recovery Network– May 2014

 

Sharp Rise in ER Visits Tied to Abuse of Sedative, Study Finds

“There’s been a steep increase in the number of Americans being treated at emergency departments for abuse of the sedative alprazolam, best known as Xanax, federal officials reported Thursday.

The number of emergency department visits related to abuse of alprazolam (brand names Xanax, Xanax XR, and Niravam) climbed from more than 57,000 in 2005 to nearly 124,000 in 2011, according to the U.S. Substance Abuse and Mental Health Services Administration (SAMHSA).

In the United States, alprazolam was the most commonly prescribed psychiatric medication in 2011 and the 13th highest-selling medication in 2012, the report said.”

http://consumer.healthday.com/mental-health-information-25/addiction-news-6/jump-in-er-visits-tied-to-xanax-abuse-study-finds-688047.html

Source: HealthDay.com -May 22, 2014

Methadone Programs Can be Key in Educating, Treating Hepatitis C Patients

liver“People who inject drugs and are enrolled in a drug treatment program are receptive to education about, and treatment for, hepatitis C virus, according to a study by researchers at several institutions, including the University at Buffalo.

That finding, published online this week in the Journal of Addiction Medicine will be welcome news to health care providers. “One of the most important findings of this work is that people who inject drugs do want to be educated about the disease and that education is associated with willingness to be treated,” says senior author Andrew H. Talal, MD, professor of medicine in the Division of Gastroenterology, Hepatology and Nutrition at UB and adjunct associate professor of medicine at Weill Cornell Medical College. research assistant professor of medicine at UB.”

http://www.sciencedaily.com/releases/2014/05/140516203359.htm

Source: ScienceDaily.com -May 16, 2014

Blog By Jana Burson: The COWS Score: How Helpful Is It?

“COWS stands for Clinical Opioid Withdrawal Scale, and it’s probably the most commonly used tool to determine the degree of opioid withdrawal experienced by the patient. The scale has eleven items related to opioid withdrawal. Some are subjective, like the question about the degree of anxiety or irritability the patient is feeling. Some items are strictly objective, such as pupil size and pulse rate. And some are sort of a combination of objective and subjective, like the question asking about both nausea and vomiting. The patient may report nausea and score points on the scale, and if the patient vomits, this scores more points.

I think it’s a good tool, but has some drawbacks. I use it during dose induction, particularly on a patient new to medication-assisted treatment. Sometimes patients aren’t sure how they’re “supposed” to feel on replacement medication, and a COWS score gives me a better idea of how much withdrawal they are in.”

The blog can be accessed at: http://janaburson.wordpress.com/2014/05/25/the-cows-score-how-helpful-is-it/

Source: JanaBurson.com – May 25, 2014

See Who’s Being Hurt by America’s Growing Prescription Drug Addiction

pills 12-20-12America’s burgeoning prescription drug addiction affects wide segments of society, including women, veterans, teens, healthcare providers and the middle and upper-middle class. This article provides some interesting statistics on these segments of society.

http://cironline.org/blog/post/see-who%E2%80%99s-being-hurt-americas-growing-prescription-drug-addiction-6359

Source: The Center for Investigative Reporting – May 13, 2014

Seniors and Prescription Drugs: As Misuse Rises, So Do the Toll

seniors“To assess the scope and impact of the prescription drug problem among older Americans, USA TODAY studied data from an array of federal agencies and private firms. Key findings:

  •  More prescriptions: The medical community is increasingly giving older patients prescriptions for two especially addictive drug classes: opioid pain relievers and benzodiazepines, psychoactive medications such as Xanax and Valium often used for anxiety. According to data collected from IMS Health, which tracks drug dispensing for the government, the 55 million opioid prescriptions written last year for people 65 and over marked a 20% increase over five years — nearly double the growth rate of the senior population. The number of benzodiazepine prescriptions climbed 12% over that period, to 28.4 million.
  • More misuse: In 2012, the average number of seniors misusing or dependent on prescription pain relievers in the past year grew to an estimated 336,000, up from 132,000 a decade earlier, according to survey data from the Substance Abuse and Mental Health Services Administration (SAMHSA). Misuse is defined as using the drugs without a prescription or not as prescribed.
  •  More damage: Among people 55 and older seeking substance abuse treatment from 2007-11, there was a 46% jump in the share of cases involving prescription narcotics, SAMHSA data show. Annual emergency room visits by people 65 and over for misuse of pharmaceuticals climbed more than 50% during that time, to more than 94,000 a year. And the rate of overdose deaths among people 55 and older, regardless of drug type, nearly tripled from 1999-2010, to 9.4 fatalities per 100,000 people, based on data from by the Centers for Disease Control and Prevention.”

http://www.usatoday.com/story/news/nation/2014/05/20/seniors-addiction-prescription-drugs-painkillers/9277489/

Source: USAToday.com – May 25, 2014

Pioneer Voices Blog by William White

“When I launched my website in 2010, it seemed a perfect venue to create an archive where interviews could be made available worldwide at the click of a mouse.  Since then, I have more than 100 interviews with addiction treatment and recovery advocacy pioneers.  I would like to call your attention to several of these recently posted interviews.”

  • Dr. Stephanie Covington explores the evolution of her pioneering work in the development of gender-specific treatment and recovery support services in the United States.
  • Karen Moyer and Brian Maus discuss the needs of children affected by addiction and the unique program they have developed to enhance the health and development of such children.
  • A.J. Senerchia is one of the leaders of a new organization, Young People in Recovery (YPR).  Young people are playing an increasingly important role in the new recovery advocacy movement, and the interview with A.J. provides background on YPR and the role of young people in this larger movement.  Very inspiring.
  • Dr. Joan Zweben has made significant contributions to the clinical treatment of addiction.   She was an early voice calling for recovery-oriented psychotherapy within addiction treatment, and she has been one of the pioneers in elevating the quality and recovery orientation of medication-assisted treatment in the U.S.  In this engaging interview, she describes her life and work.

“At the near-end of my career, I have had the pleasure of learning insights gleaned from the lives of these and other pioneers in the addictions field.  What I would have given to have had such access when I began this work in the 1960s.  For those at all stages of your careers, here is such an opportunity.” The 100+ interviews are posted at: http://www.williamwhitepapers.com/leadership_interviews/

Source: WilliamWhitePapers.com – May 24, 2014

Painkiller Overdose Deaths Have Tripled: Government Report

“Overdose deaths from prescription narcotics tripled from 2009-2010, compared with a decade earlier, according to a new government report. Almost half of Americans are taking one or more prescription medications, the report found. An estimated 10.5 percent are prescribed painkillers.

The report found a large jump in the percentage of Americans taking prescription medication, according to HealthDay. From 2007 to 2010, about 48 percent of people said they were taking a prescription drug, up from 39 percent from 1988 to 1994.

About 90 percent of adults ages 64 and older took prescription medication in the past month, while 25 percent of children did so. About 10 percent of Americans said they had taken five or more prescription drugs in the previous month.”

http://www.drugfree.org/join-together/prescription-drugs/painkiller-overdose-deaths-have-tripled-government-report

Source: JoinTogether.org – May 15, 2014

Now Available From SAMHSA – Prescription Drug Abuse Fact Sheets

ROUND PILLSWould you like to add your organization’s name to any of a growing list of 20 SAMHSA prescription drug abuse fact sheets?

SAMHSA’s Preventing Prescription Abuse Workplace (PAW) Technical Assistance Center is pleased to offer reproducible PDFs of its 30 fact sheets with customized names added at no charge. The fact sheets are not copyrighted, and you are free to download them from the link, reproduce or print them in bulk, or reuse our text in your materials.

Two of the fact sheets introduced in May include: Prescription Drug Misuse Among Older Adults and Understanding The Problem and Youth and Prescription Drug Abuse.

The fact sheets can be accessed at: http://www.hsc.wvu.edu/icrc/Pages/SAMHSA-Prevention-of-Prescription-Drug-Abuse-in-th/SAMHSA-Fact-Sheets

Source: The Substance Abuse Mental Health Services Administration- May 2014

Other National News of Interest

State News of Interest

New York – New York Senator Requests $100 Million in Federal Funding to Curb Heroin Trade – 5/27/14
http://www.drugfree.org/join-together/new-york-senator-requests-100-million-in-federal-funding-to-curb-heroin-trade

News & Updates – May 16, 2014; Issue 200

Compiled & Edited by Sue Emerson – Publisher

Prior Edition: April 25, 2014

List of all News/Updates

MEDICATION-ASSISTED TREATMENT (MAT) AND OPIOID ABUSE/ADDICTION

GOVERNMENT

PRESCRIPTION DRUG MONITORING

OTHER NATIONAL NEWS OF INTEREST

NEWS FROM THE STATES

Buprenorphine, Methadone and Opiate Replacement Therapy Blog Series from Psychology Today

blog1This three part blog by Joseph Troncale, MD, FASAM, published online on the Psychology Todaywebsite provides a historical overview of opioid addiction and the rise of opioid replacement medication.  The three parts include:

Part 1: Lessons From History – April 30, 2014

Part II: Where the Harrison Act has Brought Us – May 10, 2014

Part III: The Plight of the Opiate Addict from 1914 until Now, and the Rise of Substitution Therapy – May 10, 2014

Dr. Troncale concluded, “There is no perfect drug or therapy, but it is still a certainty that the use of street heroin or synthetic opiates is extremely lethal. I have seen people use NA or AA and get clean, and I have seen people use a combination of buprenorphine or methadone and/or AA and live normal lives. The hope of change is still there. Why people make destructive choices is the question that cannot be explained except by an understanding of the power of the limbic system.”

Source: PsychologyToday.com – April/May 2014

Opioid Substitution Therapy Is Linked to Lowered HIV Risk

“Methadone maintenance therapy and treatment with buprenorphine-naloxone are equally effective at reducing HIV injecting risk behaviours among people who inject drugs, investigators from the United States report in the online edition of the Journal of Acquired Immune Deficiency Syndromes.

Both treatments were associated with significant reductions in injecting practices linked to a risk of HIV transmission. Sexual risk behaviour also decreased in women taking both therapies. However, drop-out rates were higher among people treated with buprenorphine-naloxone and men taking this therapy reported significantly higher rates of sexual risk-taking.”

http://www.aidsmap.com/Methadone-and-buprenorphine-naloxone-both-associated-with-reduced-HIV-risk-among-people-who-inject-drugs/page/2849368/

Source: Aidsmap.com – April 29, 2014

NYC: National Development and Research Institutes, Inc. (NDRI) Honors Dr. Beny J. Primm for Lifetime Contribution to the Fields of Addiction and Its Related Diseases

Primm“Dr. Beny J. Primm was recently honored by the National Development and Research Institutes, Inc. (NDRI) and presented with the Lifetime Contribution Award by Dr. H. Westley Clark, MD, and Mr. Joseph Lunievicz at The Masonic Temple on at 71 West 23rd Street, NY, NY.

Dr. Primm is the co-founder of Addiction Research Treatment Corporation (Now known as SMART) served as its Executive Director for more than 40 years, and as President of the Urban Resource Institute since its creation in 1980. Selected by four U.S. Presidents to serve as a consultant on a variety of substance abuse and public health issues, he was appointed to the Commission on AIDS by President Ronald Reagan, selected as the first Director of the Center for Substance Abuse Treatment of the US Department of Health and Human Services by President George Bush, and named U.S. Representative on issues of drug addiction and AIDS to the World Health Organization in Geneva.”

http://wcalvinanderson.wordpress.com/tag/american-association-for-the-treatment-of-opioid-dependence/

Source: Calvin Anderson – April 28, 2014

E-mail Communication from AATOD President Mark Parrino on MAT for Opioid Addiction in the Criminal Justice System

AATOD“I am providing a link to an important letter to Attorney General Eric Holder, dated April 10, 2014, which was signed by sixteen US Senators. The Senators are urging the Attorney General to work with all of the branches in the Department of Justice to utilize the federally approved medications to treat opioid addiction “in combination with counseling”. “Specifically, the Department should initiate a multi-state program utilizing anti-addiction medications to support successful reentry into society of opioid addicted offenders from various correctional settings.” I know that you will join me in supporting this approach and clearly the sixteen Senators understand the benefit of providing access to Medication Assisted Treatment for opioid addiction in the Criminal Justice setting.”

The AATOD letter can be accessed at: http://www.aatod.org/wp-content/uploads/2014/04/Letter-to-AG-Holder-on-Prescription-opioid-and-heroin-addiction.pdf

Source: American Association for the Treatment of Opioid Dependence – April 28, 2014

Blog by Jana Burson Methadone and Buprenorphine During Incarceration

jail-cropped“As a health care provider, of course I’m opposed to any refusal to treatment a patient while incarcerated. I think it’s a violation of the 8th Amendment about cruel and unusual punishment, but since I’m no legal scholar, I’ve searched the internet for more information about this situation. I found a great article co-authored by a doctor and a lawyer. They make the point that opioid addiction is a complex illness, and forced withdrawal causes severe physical and psychological suffering. Also, because opioid withdrawal makes people especially vulnerable, they may be coerced into giving testimony that incriminates themselves. They are less able to make decisions.

Prisons are charged to provide as much care as is available to prisoners as general population, yet opioid addicts are denied access to medication-assisted treatments for addiction. These treatments are, as you probably know if you’re a regular reader of this blog, one of the most evidenced-based medical treatments in all of medicine.”

http://janaburson.wordpress.com/2014/05/11/methadone-and-buprenorphine-during-incarceration/

Source: JanaBurson.com – May 11, 2014

Site last updated July 17, 2014 @ 5:55 pm