title: Promethazine use among chronic pain patients.
abstract: BACKGROUND
  Concomitant use of opioids and promethazine has been reported in various subpopulations, including methadone maintenance patients, injection drug users, and at-risk teenagers. Promethazine is thought to potentiate the "high" from opioids. However, to date, the prevalence of promethazine use has not been determined among patients prescribed opioids for chronic pain.
  
  
  METHODS
  Urine samples from 921 patients prescribed opioids for chronic pain were analyzed for promethazine. Demographic data, toxicology results, and opioid prescription information were obtained through medical record abstraction. We assessed the prevalence and factors associated with promethazine use with bivariable and multivariable statistics.
  
  
  RESULTS
  The prevalence of promethazine-positive urine samples among chronic pain patients was 9%. Only 50% of promethazine-positive patients had an active prescription for promethazine. Having benzodiazepine-positive urine with no prescription for a benzodiazepine was statistically associated with promethazine use. Also, having a prescription for methadone for pain or being in methadone maintenance for the treatment of opioid dependence were both statistically associated with promethazine use. Chronic pain patients prescribed only a long-acting opioid were more likely to have promethazine-positive urines than patients prescribed a short-acting opioid.
  
  
  CONCLUSIONS
  The study provides compelling evidence of significant promethazine use in chronic pain patients. Promethazine should be considered as a potential drug of abuse that could cause increased morbidity in opioid-using populations.
authors.affiliation: Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA, United States. Electronic address: kara.lynch@ucsf.edu.
authors.forename: Kara L
authors.initials: KL
authors.lastname: Lynch
authors.affiliation: Department of Family and Community Medicine, University of California San Francisco, San Francisco, CA, United States; Department of Psychiatry, University of California San Francisco, San Francisco, CA, United States.
authors.forename: Brad J
authors.initials: BJ
authors.lastname: Shapiro
authors.affiliation: Department of Family and Community Medicine, University of California San Francisco, San Francisco, CA, United States.
authors.forename: Diana
authors.initials: D
authors.lastname: Coffa
authors.affiliation: RTI International, Behavioral Health Epidemiology, Research Triangle Park, NC, United States.
authors.forename: Scott P
authors.initials: SP
authors.lastname: Novak
authors.affiliation: RTI International, Urban Health Program, San Francisco, CA, United States.
authors.forename: Alex H
authors.initials: AH
authors.lastname: Kral
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000701:Analgesics, Opioid / Q000627:therapeutic use; D059350:Chronic Pain / Q000188:drug therapy*; D005260:Female; D006634:Histamine H1 Antagonists / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008691:Methadone / Q000627:therapeutic use; D008875:Middle Aged; D009294:Narcotics / Q000627:therapeutic use; D058850:Opiate Substitution Treatment; D009293:Opioid-Related Disorders / Q000534:rehabilitation; D063487:Prescription Drug Misuse / Q000706:statistics & numerical data*; D011398:Promethazine / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D006634:Histamine H1 Antagonists; D009294:Narcotics; D011398:Promethazine; D008691:Methadone
keywords: Chronic pain; Opioids; Pain management; Prescription drug abuse; Promethazine