Introduction

Reasonably one can be concerned in patients with known drug dependence that their dependence will interfere with pain treatment, particularly treatment of pain with opioids. Concerns centre mainly on fears of addiction relapse when patients are given addictive drugs in the medical setting, but there may also be issues with drug interactions, with dosing for active users or with drug seeking for recreational use. Drug dependence does not preclude using addictive drugs during medical treatment of pain, but it does introduce several complications that must be considered when treating these patients. The acute pain, pain at the end of life and chronic pain situations are different, and are treated as separate entities in this chapter. The chapter focuses on dependence during chronic pain treatment, since this is where most of the complexities of concurrent pain and substance dependence arise.

Defining Addiction

Much effort has been placed towards developing uniform criteria and descriptors for addiction, so that it becomes a recognised medical condition and patients with addiction can thereby gain access to addiction treatment. These efforts have culminated in the American Psychiatric Association’s DSM IV criteria (Table 11.1), reflected also in the ICD-10 and WHO classifications of addiction and addiction terminology, which use the term ‘substance dependence’ to denote what would in general parlance be termed ‘drug addiction’. Unfortunately, although the definitions did satisfy the need to medicalise addiction, it later became difficult to define and identify addiction in patients treated with opioids for pain, because these patients develop opioid dependence without necessarily reaching the criteria for addiction. This has produced much confusion and a great deal of difficulty in defining addiction and assessing addiction rates in opioid treated pain patients, to the extent that as new criteria are being developed in DSM V the word, dependence, will be dropped.

Source: American Psychiatric Association (1994) Diagnostic and Statistical Manual of Mental Disorders, 4th edn. Washington, DC: American Psychiatric Association.

Table 11.1 DSM IV Substance abuse and dependence criteria

Source: Savage, S, Covington, EC, Ehit, HA, Hunt, J, Joranson, D & Schnoll, SH (2001) Definitions related to the use of opioids for the treatment of pain. A Consensus Document From the American Academy of Pain Medicine, the American Pain Society, and the American Society of Addiction Medicine.

DSM-IV Substance Abuse Criteria
A. A maladaptive pattern of substance use leading to clinically significant impairment or distress, as manifested by one (or more) of the following, occurring within a 12-month period:	recurrent substance use resulting in a failure to fulfill major role obligations at work, school or home recurrent substance use in situations in which it is physically hazardous recurrent substance-related legal problems continued substance use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of the substance
B. The symptoms have never met the criteria for Substance Dependence for this class of substance
DSM-IV Substance Dependence Criteria
Addiction (termed substance dependence by the American Psychiatric Association) is a maladaptive pattern of substance use leading to clinically significant impairment or distress, as manifested by one (or more) of the following, occurring within a 12-month period:	Tolerance, as defined by either of the following: (a) A need for markedly increased amount of the substance to achieve intoxication or the desired effect or (b) Markedly diminished effect with continued use of the same amount of the substance Withdrawal, as manifested by either of the following: (a) The characteristic withdrawal syndrome for the substance or (b) the same (or closely related) substance is taken to relieve or avoid withdrawal symptoms The substance is often taken in larger amounts or over a longer period than intended. There is a persistent desire or unsuccessful efforts to cut down or control substance use. A great deal of time is spent in activities necessary to obtain the substance, use the substance, or recover from its effects. Important social, occupational, or recreational activities are given up or reduced because of substance use. The substance use is continued despite knowledge of having a persistent physical or psychological problem that is likely to have been caused or exacerbated by the substance (for example, current cocaine use despite recognition of cocaine-induced depression or continued drinking despite recognition that an ulcer was made worse by alcohol consumption)
Substance dependence may be:	with physiologic dependence (evidence of tolerance or withdrawal) or without physiologic dependence (no evidence of tolerance or withdrawal)

NOTE: Unlike the criteria for Substance Dependence, the criteria for Substance Abuse do not include tolerance, withdrawal or a pattern of compulsive use, and instead include only the harmful consequences of repeated use. The term abuse should be applied only to a pattern of substance use that meets the criteria for this disorder; the term should not be used as a synonym for ‘use’, ‘misuse’, or ‘hazardous use’. The term will not often apply to opioid-treated pain patients who generally receive continuous opioid treatment, and therefore develop tolerance and dependence.

For the purposes of this chapter, it should be considered that ‘substance dependence’ describes patients who reach DSM IV criteria for substance dependence (addiction), which includes drug tolerance, drug dependence (manifest as withdrawal when drug is tapered or withdrawn) and at least one of the aberrant behaviours described by criteria. It is important to note here that all patients treated chronically with opioids may demonstrate opioid tolerance and dependence, but unless they also exhibit opioid seeking behaviours, such as compulsive use and craving, they do not meet the criteria for addiction (Table 11.2).

Table 11.2 Definitions related to the use of opioids for the treatment of pain

I Addiction

Addiction is a primary, chronic, neurobiologic disease, with genetic, psychosocial, and environmental factors influencing its development and manifestations. It is characterized by behaviours that include one or more of the following: impaired control over drug use, compulsive use, continued use despite harm, and craving.

II Physical Dependence

Physical dependence is a state of adaptation that is manifested by a drug class specific withdrawal syndrome that can be produced by abrupt cessation, rapid dose reduction, decreasing blood level of the drug, and/or administration of an antagonist.

III Tolerance

Tolerance is a state of adaptation in which exposure to a drug induces changes that result in a diminution of one or more of the drug’s effects over time.

Treating Acute Pain

It is safe to say that addiction virtually never develops de novo from opioid treatment of acute pain. The exception might be the case when acute pain progresses through subacute pain to chronic pain, and opioid use becomes long term rather than short term. Provided opioid use is structured and supervised, as it usually is in the acute pain setting, particularly when treating post-operative or post-trauma pain, addiction rarely develops. There may be a concern, however, in patients who already carry a current or past substance dependence diagnosis, that opioid treatment of pain could trigger a worsening or relapse of the condition. When a patient with a substance dependence diagnosis expresses such concern it may be helpful to avoid opioids or other addictive medications (e.g. benzodiazepines) wherever possible.

In general, the principle of management of acute pain in substance-dependent patients is to treat pain using whatever treatment best relieves the pain, including using opioids as needed. The acute pain setting is not the right setting for initiating or continuing active addiction treatment, but when known substance abusers are under care, plans should be made for addiction treatment after the acute pain episode. A number of drug interactions may arise during surgery and anaesthesia, and during acute pain treatment, when substance dependence is active; these are summarised in Table 11.3. In particular, substance-dependent patients using opioids will manifest tolerance as resistance to opioids, and the need to use large opioid doses to achieve analgesia. Another feature of chronic opioid use is a narrowing of the therapeutic window, reducing the safety margin and risking respiratory depression despite inadequate analgesia. This makes it advisable to maximise the use of non-opioid pain interventions, such as neuraxial and regional anesthesia and non-steroidal anti-inflammatory drugs (NSAIDs), to obviate the need for opioids wherever possible.

Source: Ballantyne, JC (2008) Psychiatric disease, chronic pain and substance abuse. In:Sweitzer, B-J (ed.) Handbook of Preoperative Assessment and Managment, 2nd edn. Philadelphia, PA:Lippincott Williams and Wilkins.

Table 11.3

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