Search PubMed⌕ Search

Biomedical subjects

Douglas Gourlay

Publications and source records attributed to Douglas Gourlay.

7 recordsLinked to original sources
PubMed2005

Review article: perioperative pain management of patients on methadone therapy.

PURPOSE: Methadone, an opioid traditionally associated with the management of opioid addictive disorders, has been prescribed increasingly as an analgesic for the management of various chronic pain conditions. Despite the increasing popularity of methadone, most anesthesiologists are not familiar with its complex pharmacology. The purpose of this article is to review the pharmacology of methadone and to suggest a management algorithm for the perioperative care of methadone patients. SOURCE: A Medline search was performed to obtain the published literature on the pharmacology of methadone and its use perioperatively. PRINCIPAL FINDINGS: The complexity of methadone's pharmacology is characterized by a high inter-individual variability, a potential for interaction with other medications, and a long elimination half-life. The postoperative management of methadone patients may be difficult as they are often 'opioid-tolerant' but may be 'pain-intolerant'. For those patients who are taking part in methadone-maintenance programs, there is a potential for the problematic use of opioids or other substances. The management plan for patients taking methadone may differ depending on the type of surgery and the associated perioperative differences in fasting status and gastrointestinal function. In consideration of all the factors listed above, a management algorithm is outlined for the perioperative care of methadone patients. CONCLUSION: Methadone is an opioid with complex properties, and a patient that is taking methadone can represent a unique challenge to the anesthesiologist. A good understanding of the pharmacology of methadone and of the type of patients on this medication will help to improve their perioperative care.

Drug Interactions↗
PubMed2005

Addiction and pain medicine.

The adequate cotreatment of chronic pain and addiction disorders is a complex and challenging problem for health care professionals. There is great potential for cannabinoids in the treatment of pain; however, the increasing prevalence of recreational cannabis use has led to a considerable increase in the number of people seeking treatment for cannabis use disorders. Evidence that cannabis abuse liability is higher than previously thought suggests that individuals with a history of substance abuse may be at an increased risk after taking cannabinoids, even for medicinal purposes. Smoked cannabis is significantly more reinforcing than other cannabinoid administration methods. In addition, it is clear that the smoked route of cannabis delivery is associated with a number of adverse health consequences. Thus, there is a need for pharmaceutical-grade products of known purity and concentration using delivery systems optimized for safety. Another factor that needs to be considered when assessing the practicality of prescribing medicinal cannabinoids is the difficulty in differentiating illicit from prescribed cannabinoids in urine drug testing. Overall, a thorough assessment of the risk/benefit profile of cannabinoids as they relate to a patient's substance abuse history is suggested.

Analgesics↗
PubMed2004

Prescription opioid abuse in patients presenting for methadone maintenance treatment.

To characterize prescription opioid dependent patients in a methadone maintenance treatment (MMT) program, a detailed retrospective chart review of new admissions (1997-1999, n=178, mean age=34.5+/-0.7 years, 65% male) was conducted. At admission most patients (83%) had been using prescription opioids (+/-heroin). Four groups were identified: 24% had used prescription opioids only; 24% used prescription opioids initially and heroin later; 35% used heroin first and prescription opioids subsequently; and 17% had used heroin only (this group was significantly younger: mean age 26+/-1 years, P=0.0001). Subjects reported regular use of prescription opioids at higher than therapeutic dosages. For example, in the 'prescription opioid only' group the reported mean (+/-S.E.) number of codeine or oxycodone-containing tablets consumed daily was 23 (+/-6) tablets and 21 (+/-3) tablets, respectively. There were no significant differences found amongst the groups in measures of social stability. Those dependent on prescription opioids alone were less likely to use illicit non-opioid drugs or to be associated with injection drug use. Those that used prescription opioids only or initially were more likely to have ongoing pain problems and to be involved in psychiatric treatment. Further research is required to better elucidate the complex relationships between pain, mental health and addiction in order to develop optimal prevention and treatment strategies for prescription opioid dependence.

Adult↗
PubMedDate not supplied

Evidence of morphine metabolism to hydromorphone in pain patients chronically treated with morphine.

Minor metabolic pathways in human subjects have been shown to exist for the conversion of codeine to hydrocodone but have not been reported for the metabolic conversion of morphine to hydromorphone. In this study, urine specimens were collected in an out-patient setting from 13 pain patients who were chronically treated with morphine and other opioids (methadone, oxycodone, and fentanyl). The chronic pain patients were chosen for study because they were treated with high-dose morphine and had no personal or family history of addiction. Results of the initial evaluation and follow up of these patients with random urine tests did not indicate opioid misuse. The specimens were analyzed by GC-MS for the presence of hydromorphone. The reporting limit for hydromorphone was 100 ng/mL. Ten of the 13 morphine-treated patients excreted hydromorphone in minor amounts ranging 120 to 1400 ng/mL. Concurrent morphine concentrations were exceedingly high in these 10 patients and frequently exceeded the upper limit of linearity (> 10,000 ng/mL) of the assay. The ratio of hydromorphone to morphine ranged from 0.015 to 0.024. Morphine concentrations in the three patients in which hydromorphone was not detected tended to be lower than those observed in other patients. For comparison, one additional patient was included in the study, who was prescribed both morphine and hydromorphone. Concentrations of hydromorphone in this patient were in the range of 3400-13,000 ng/mL, while concurrent morphine concentrations were in the range of 3200-6600 ng/mL. These data are highly suggestive that hydromorphone can be produced as a minor metabolite of morphine in humans. Although additional studies in more restricted settings are needed, it is recommended that interpretation of low urinary concentrations of hydromorphone in combination with high concentrations of morphine in morphine-treated pain patients should not be considered as conclusive evidence of hydromorphone misuse.

Adult↗