Special issues and concerns in the evaluation of older adults who have pain

Options for treating postherpetic neuralgia in the medically complicated patient

Patients with postherpetic neuralgia (PHN) are often of advanced age or immunocompromised and likely to have ≥1 comorbid medical condition for which they receive ≥1 medication (polypharmacy). Comorbidities affecting renal or hepatic function can alter pharmacokinetics, thereby impacting the efficacy or tolerability of PHN analgesic therapies. Cardiovascular, cerebrovascular, or psychiatric comorbidities may increase patient vulnerability to potential adverse events associated with some PHN analgesic therapies. Because PHN is a localized condition, localized therapy with a topical analgesic (lidocaine patch 5% and capsaicin 8% patch or cream) may provide adequate efficacy while mitigating the risk of systemic adverse events compared with oral analgesics (eg, tricyclic antidepressants, anticonvulsants, opioids). However, combined therapy with a topical and an oral analgesic or with >1 oral analgesic may be needed for optimal pain management in some patients. This review summarizes how comorbidities and concomitant medications should be taken into account when selecting among available pharmacotherapies for PHN and provides recommendations for the selection of therapies that will provide analgesia while minimizing the risk of adverse events.

Correlates of non-medical prescription drug use among a cohort of injection drug users in Baltimore City

Despite reports of increasing non-medical prescription drug use, relatively few studies have systematically evaluated the prevalence and correlates of non-medical prescription drug use, particularly in populations that might be especially vulnerable (e.g., injection drug users [IDUs]). We examined factors associated with non-medical prescription drug use among a community-based cohort of current and former IDUs in Baltimore (The ALIVE Study). We conducted a cross-sectional analysis of data from cohort participants that responded to a survey that included questions on non-medical prescription drug use between 2005-06 (n=1320). Non-medical prescription drug use was considered to be use of any of the following: Opiates (Oxycontin, Percocet), Benzodiazepines or Clonidine, purchased on the street and taken orally within the last six months. Data on other covariates of interest (e.g., demographics, substance use, general health) was obtained through a standardized interview. The median age was 46 years; 66% were male, 85% were African-American. Twenty one percent reported any non-medical prescription drug use; 12% reported using more than one drug. Non-medical use of opiates was most common (17%). In multivariate analysis, non-medical prescription drug use was significantly associated with Caucasian race (prevalence ratio [PR]: 1.79), self-reported bodily pain (PR: 1.58), hazardous alcohol use (PR: 1.47), marijuana use (PR: 1.65), non-injection cocaine/heroin use (PR: 1.70), diverted use of buprenorphine (PR: 1.51) or methadone (PR: 2.51), and active injection drug use (PR: 3.50; p<0.05 for all). The association between bodily pain and non-medical prescription drug use was stronger among persons that were not using substances (marijuana, injecting drugs, snorting/smoking heroin, cocaine, using crack) as compared to those using these substances. The high prevalence of non-medical prescription drug use among this population warrants further research and action. Information on the risks of nonmedical prescription drug use especially overdose, should be incorporated into interventions targeted at IDUs.

Opioid therapy for osteoarthritis and chronic low back pain

BACKGROUND

Chronic low back pain (CLBP) and osteoarthritis (OA) of any joint are highly prevalent, occurring in > 50% of US adults aged ≥ 60 years. Opioids are prescribed more frequently for CLBP and OA than for any other noncancer pain, and the judicious use of opioids is recommended by treatment guidelines for the management of CLBP and OA pain.

OBJECTIVE

To review the appropriate role of opioid analgesics in the treatment of patients with moderate-to-severe pain due to CLBP or OA and provide recommendations for best practices when prescribing opioids.

METHODS

Articles were identified through a search of PubMed. Additional references were identified for inclusion from the reference lists of articles identified via the literature search, treatment guidelines, and Cochrane Reviews.

RESULTS

The available data suggest that opioid therapy represents a valuable treatment option in patients who do not respond to other analgesics and in whom the potential benefits of treatment outweigh the potential risks. Prescribing physicians need to perform vigilant patient screening and monitoring for signs of abuse, intervene promptly to manage or prevent adverse events and drug interactions, tailor opioid therapy to individual patients' comorbidities, and know how to switch or rotate opioids to find the best treatment option.

CONCLUSIONS

Prescribers need to understand the place of opioid therapy in a multimodal treatment program that includes patient rehabilitation to reduce pain and improve function. The analgesic benefits of opioids must be balanced against concerns about addiction and abuse, adverse events, and their potential impact on other aspects of treatment.

Implications of opioid analgesia for medically complicated patients

Opioid analgesics have an established role in the management of postoperative pain and cancer pain, and are gaining acceptance for the management of moderate to severe chronic noncancer pain, most notably chronic low back pain and osteoarthritis, that does not respond to other interventions. Many patients with chronic pain have co-morbid medical conditions that may complicate opioid therapy. Selecting the appropriate opioid requires knowledge of how individual opioids differ with respect to metabolism and interaction with concurrent medications, as well as the reasons why specific medical conditions may influence their efficacy and tolerability. Polypharmacy is a common complicating condition in the elderly and in patients with psychiatric illness, cancer, cardiovascular disease, diabetes mellitus or other chronic illnesses. Polypharmacy, though often necessary for patients with multiple medical conditions, also multiplies the risk of drug interactions. Pharmacokinetic drug interactions can increase or reduce exposure to the opioid or concurrent medications, reducing efficacy and/or tolerability and increasing toxicity. Pharmacodynamic interactions can enhance the depressive effects of opioids, compromising safety. Patients with impaired renal or hepatic function may have difficulty clearing or metabolizing opioids and concurrent medications, leading to increased risk of adverse events. Patients with cardiovascular, cerebrovascular or respiratory disease (including smokers of >/=2 packs/day with no other diagnosis) may be more susceptible to respiratory depression, bradycardia and hypotension with any opioid, and a few specific opioids pose additional risks. Patients with cerebrovascular disease, dementia, brain injury or psychiatric illness are more susceptible to opioid effects on the CNS, which can include euphoria, cognitive impairment and sedation. Appropriate opioid selection may mitigate these effects. Even in older patients, addiction, abuse and misdirection of prescribed opioids are of concern. Higher risk exists for patients with psychiatric illness, history of substance abuse, and identifiable substance abuse risk factors. Screening for abuse potential and vigilant patient monitoring should be routine. Opioids differ in their ability to produce euphoria, based on opioid receptor agonism, but substance abusers may be more influenced by availability, familiarity and cost factors. Consequently, opioid selection has limited influence on abuse potential but can facilitate ease of monitoring. This review provides an overview of opioid use in medically complicated patients and recommendations on how to optimize analgesia while avoiding adverse events and drug interactions in the clinical setting. Articles cited in this review were identified via a search of EMBASE and PubMed. Articles selected for inclusion discussed characteristics of specific opioids and general physiological aspects of opioid therapy in important patient populations.