From the Guidelines
Intravenous (IV) hydromorphone is generally less constipating than oral (PO) hydromorphone. This difference occurs because IV administration bypasses first-pass metabolism in the liver, resulting in less drug exposure to the gastrointestinal tract where opioids exert their constipating effects by binding to mu-opioid receptors. When hydromorphone is given orally, a larger portion of the drug directly interacts with receptors in the gut, slowing intestinal motility, decreasing secretions, and increasing water absorption from the bowel. However, it's essential to note that all opioids, including hydromorphone, can cause constipation regardless of administration route, as highlighted in a study on palliative care in the ICU 1.
For patients receiving hydromorphone by either route, prophylactic bowel regimens should be implemented, typically including:
- Stool softeners like docusate sodium (100-300 mg daily)
- Stimulant laxatives such as senna (8.6-17.2 mg daily)
- Osmotic agents like polyethylene glycol (17 g daily) Adequate hydration and physical activity, when possible, should also be encouraged to minimize constipation risk. The management of cancer pain guidelines also support the use of opioids like hydromorphone for moderate to severe pain, with consideration of their potential side effects, including constipation 1.
It's crucial to weigh the benefits and risks of long-term opioid use, considering not only pain relief but also improvements in function and quality of life, especially in cancer survivors 1. Given the potential for constipation with all opioids, regardless of the route of administration, a proactive approach to managing this side effect is necessary to optimize patient outcomes in terms of morbidity, mortality, and quality of life.
From the Research
Opioid-Induced Constipation
- Opioid-induced constipation (OIC) is a common adverse effect of opioid analgesic therapy that significantly affects the patient's quality of life and may lead to poor adherence and treatment failure 2.
- The degree of constipation can be evaluated using the Bowel Function Index (BFI), with higher scores indicating more severe constipation 2.
Hydromorphone and Constipation
- There is no direct comparison between IV hydromorphone and PO hydromorphone in terms of constipation in the provided studies.
- However, it is known that oral bioavailability of hydromorphone is low, and the kidney excretes hydromorphone and its metabolites 3.
- A study comparing the pharmacokinetics of intravenous, oral immediate-release, and oral extended-release formulations of hydromorphone found that the bioavailability of hydromorphone was higher for the extended-release formulation compared to the immediate-release formulation 4.
Opioid Comparison
- Tapentadol, oxycodone/naloxone, and some transcutaneous opioids were associated with less frequent OIC than morphine or oxycodone in controlled clinical trials 2.
- Hydromorphone was found to be associated with more severe constipation in a multiple linear regression analysis, especially when interacting with morphine equivalent dose 2.
Constipation Treatment
- There is good evidence to support the use of polyethylene glycol (PEG), tegaserod, lactulose, and psyllium for the treatment of chronic constipation 5.
- Stimulant laxatives, such as bisacodyl and sodium picosulfate, are associated with harmful long-term colonic effects and possible carcinogenic risk, and evidence does not support their use for more than four weeks 6.