Fast Fact and Concept #018; Oral Opioid Dosing Intervals

2nd Edition

Author(s): David E. Weissman, MD

Oral opioids are among the most commonly prescribed drugs in palliative care. Despite national analgesic guidelines, the use of excessive intervals for short-acting oral opioids continues to pose a significant barrier to good analgesic care. Understanding the pharmacological rational for dosing intervals is key to proper prescribing and patient counseling.

Short-Acting Oral Opioids

Short-acting products are administered as either single agents (oral morphine, hydromorphone, oxycodone and codeine) or as combination products containing acetaminophen, aspirin or ibuprofen. For all these products, the peak analgesic effect occurs in 60-90 minutes with an expected total duration of analgesia of 2-4 hours. Standard reference sources generally cite a 4 hour dosing interval for the single-agent opioids, but 4-6 or 6 hour intervals for combination products (PDR, Micromedex). However, the Agency for Health Care Policy and Research (AHCPR) Clinical Practice Guideline (1994) recommends dosing intervals for all short-acting opioids at an interval or every 3-4 hours, an interval more consistent with patient reports of pain relief and the half-life of oral opioids.

Is there a danger to more frequent drug administration? There is no danger of dosing intervals as often as every 2 hours for single agent products (e.g. morphine), in patients with normal renal function, as the peak effect will be reached in 60-90 minutes and there is rapid renal excretion. For combination products, the concern is excessive acetaminophen; and thus, if patients need opioids on an every four hour basis, it is appropriate to change to single agents without acetaminophen and/or add a long-acting opioid product so as to keep the total daily acetaminophen dose at less than 4 grams.

Summary

• Prescribe the products listed above at intervals no greater than every 4 hours.
• Closely monitor daily acetaminophen intake when combination products are used.
• Provide explicit patient/family counseling regarding safe and allowable dosing intervals.
• Review your institutional opioid policies--ask if there is a hospital policy or guidelines for oral opioid doing intervals; if not, such guidelines should be developed to help guide practice.

See related analgesic Fast Facts:

# 20 Opioid dose escalation

# 51 Opioid combination products

# 70 PRN range orders

# 74 Good and Bad analgesic orders

# 82 Why patients do not take their opioids

# 94 Writing discharge/outpatient opioid prescriptions

References:

1. Acute Pain Management Guideline Panel. Acute Pain Management: Operative or Medical Procedures and Trauma Clinical Practice Guideline. AHCPR Publication No. 92-0032. Rockville, MD. Agency for Health Care Policy and Research, US Department of Health and Human Services, Public Health. Service, 1992. (see also Management of Cancer Pain, 1994).
2. Physicians Desk Reference; PDR.Net;
3. Micromedex.com

Fast Facts were edited by David Weissman MD, Palliative Care Center, Medical College of Wisconsin until January 2007.  For comments/questions write to the current editor, Drew Rosielle MD: drosiell@mcw.edu. The complete set of Fast Facts is available at EPERC: www.eperc.mcw.edu

Copyright/Referencing Information : Users are free to download and distribute Fast Facts for educational purposes only. Citation for referencing: Weissman DE . Oral Opioid Dosing Intervals. Fast Fact and Concept #18; 2nd Edition, July 2005. End-of-Life Palliative Education Resource Center www.eperc.mcw.edu.

Disclaimer: Fast Facts provide educational information, this information is not medical advice. Health care providers should exercise their own independent clinical judgment. Some Fast Fact information cites the use of a product in dosage, for an indication, or in a manner other than that recommended in the product labeling. Accordingly, the official prescribing information should be consulted before any such product is used.

Creation Date: 6/2000; 2nd Edition, July 2005.

Purpose: Instructional Aid, Teaching

Audience(s)

ACGME Competencies: Medical Knowledge, Patient Care

Keyword(s): Pain>opioids