Incidence of constipation associated with long-acting opioid therapy: a comparative study.
BACKGROUND
Opioid therapy plays a key role in the management of chronic pain. Constipation is one of the more frequently occurring adverse effects associated with opioid therapy.


METHODS
A retrospective cohort design study was conducted to determine the incidence of constipation in chronic pain patients who received three different long-acting opioids (transdermal fentanyl, oxycodone HCl controlled-release [CR], or morphine CR) for malignant or nonmalignant chronic pain. The data source was claims data (January 1996 through March 2001) from a 20% random sample of the California Medicaid (Medi-Cal) database. Claims data were from adult patients with chronic pain (malignant or nonmalignant) who had no prior diagnosis of constipation and no prior usage of long-acting opioids for at least 3 months before the observation period. Patients were followed for at least 3 months after the initiation of opioid therapy. ICD-9 code for diagnosis of constipation was the main outcome variable. Crude rates of constipation, annual incidence density, relative risk, and adjusted odds ratios were compared.


RESULTS
A total of 1,836 patients (601 receiving transdermal fentanyl, 721 receiving oxycodone CR, and 514 receiving morphine CR) were included in the analysis. Crude (unadjusted) rates of constipation were 3.7% for transdermal fentanyl, 6.1% for oxycodone CR, and 5.1% for morphine CR (P > 0.05). Transdermal fentanyl had a lower annual incidence density and risk of constipation than oxycodone CR and morphine CR (P > 0.05). After adjusting for confounding variables, including race and supplemental opioid use, the adjusted risk of constipation was 78% greater in the oxycodone CR group (P = 0.0337) and 44% greater in the morphine CR group (P = 0.2242) than in the transdermal fentanyl group.


CONCLUSIONS
In this population, patients receiving transdermal fentanyl had a lower risk of developing constipation compared with those receiving oxycodone CR or morphine CR.
Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. pstaats@jhmi.edu
Peter S
PS
Staats
Jeffrey
J
Markowitz
Jeffrey
J
Schein
D000368:Aged; D000701:Analgesics, Opioid / Q000009:adverse effects*; D002140:California / Q000453:epidemiology; D003248:Constipation / Q000139:chemically induced* / Q000453:epidemiology; D005260:Female; D005283:Fentanyl; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009020:Morphine; D010098:Oxycodone; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D012189:Retrospective Studies
D000701:Analgesics, Opioid; D009020:Morphine; D010098:Oxycodone; D005283:Fentanyl