Sickle Cell Disease and Opioid Induced Hyperalgesia
By Stephen Agyenim-Boateng, Pharm.D.,RPh and Cassandra Trimnell
Sickle cell disease is a condition that involves chronic pain due to “sickled” cells clogging arteries and preventing blood flow and oxygen to various tissues and organs. For this reason, most sickle cell patients manage their pain with opioids and other therapies.
Opioids are usually the main stay for chronic pain management. However, the long-term use of opioids may result in a condition called opioid induced hyperalgesia (OIH). Hyperalgesia is from the Greek words hyper and algesia which means “over” and “pain”; or an increased sensitivity to pain. There are many studies that provide evidence that supports OIH as a real clinical issue that may affect patients living with sickle cell disease who use opioids for pain management.
In hyperalgesia, the systems that respond to opioids and provide pain relief are thought to change over time in a way that actually enhances pain upon contact with opioids. This pain is not necessarily located at the source of injury or disease, but rather occurs as a generalized, hard-to-define pain. It occurs even when opioid doses are increased.
OIH can often be confused with opioid tolerance or even withdrawal because symptoms can be very similar. In both tolerance and OIH, there is a decrease in the effectiveness of opioids. However, you can tell the difference between the two when a higher dose of opioids is administered. A higher dose of opioid usually provides pain relief only in tolerance and not in OIH.
Similarly, side effects such as muscle pain, cramping and abdominal pain can be found in both opioid withdrawal and OIH, in which one could easily be mistaken for the other.
Treatment for OIH is often very challenging, which is why a collaborative patient–physician relationship along with a strong support system is encouraged for successful OIH management and treatment.
One of the main management options include weaning off opioids. It can be a prolonged process and can even cause an increase of pain or mild withdrawal symptoms which emphasises the need for a patient-physician collaborative effort to ensure success. Another option to manage OIH is to switch to a different class of opioid or add alternative medications such as NSAIDs, acetaminophen, anticonvulsants or an antidepressant, which can help reduce the need for opioids. These alternative medications use different pain pathways, which reduces symptoms.
More research is warranted to further understand OIH. However for sickle cell patients on chronic opioids, it is definitely worth the conversation with their primary care providers if they experience any symptoms that mimic OIH.
