From the Research
To convert subcutaneous (SC) hydromorphone to an oral dose, multiply the SC dose by 2.5, as this is the established conversion ratio from intravenous (IV) to oral hydromorphone, and SC administration has a similar bioavailability to IV administration. For example, if a patient is receiving 2 mg of SC hydromorphone, the equivalent oral dose would be 5 mg. This conversion factor is based on the study by 1, which found a median conversion ratio of 2.5 from IV to oral hydromorphone. When switching from SC to oral administration, it's essential to ensure the patient receives an adequate dose to maintain pain control. However, individual patient factors such as age, renal function, and previous opioid exposure may necessitate dose adjustments. Monitor the patient closely after conversion for signs of either inadequate pain control or excessive sedation, and adjust the dose accordingly. Remember that hydromorphone is a potent opioid, and patients should be educated about potential side effects including constipation, nausea, and respiratory depression.
Some key points to consider when converting SC hydromorphone to oral dose include:
- The conversion ratio may vary depending on individual patient factors, such as liver and kidney function, and previous opioid exposure.
- The study by 1 found that the conversion ratio was consistent across different doses of IV hydromorphone, but higher doses (≥30 mg/day) may require a lower conversion ratio.
- Other studies, such as 2, 3, 4, and 5, provide additional information on the pharmacokinetics and pharmacodynamics of opioids, but do not directly address the conversion ratio from SC to oral hydromorphone.
- It's crucial to prioritize patient safety and monitor for signs of respiratory depression, as opioids can cause serious health complications, as discussed in 5.
The most recent and highest quality study, 1, provides the best evidence for the conversion ratio, and its findings should be prioritized when making clinical decisions.