Opioid-Induced Hyperalgesia — When Painkillers Make Pain Worse

Understanding the increased pain sensitivity linked to opioid use

What opioid-induced hyperalgesia is

Opioids are powerful pain medicines often used for short-term relief after injury or surgery and, in some cases, for chronic pain. Paradoxically, opioid-induced hyperalgesia (OIH) refers to a situation where ongoing exposure to opioids makes the nervous system more sensitive to painful stimuli instead of less. This means pain intensity may increase even while taking stronger or higher doses of the same medication.

Why it can feel confusing

OIH may look similar to other responses to opioids like tolerance (needing higher doses to achieve the same relief) or progression of the underlying condition. However, with OIH, pain becomes more widespread, diffuse, or different in quality — sometimes felt in areas not previously painful — despite increased opioid doses. Increasing the dose can actually worsen pain sensitivity rather than improve it.

How opioids affect pain processing

Long-term or high-dose opioid exposure can change how the nervous system interprets pain signals. These changes likely involve adaptations at multiple levels of the nervous system, where pathways that dampen pain are diminished and pathways that amplify pain become more active. These complex mechanisms underscore why OIH can occur even when opioids are used as prescribed.

Signs that suggest OIH

You might consider OIH if:

• Your pain becomes worse rather than better despite steady or increasing opioid doses

• Pain spreads beyond the original injury site

• You feel more sensitive to normal sensations (even light touch)

• Increasing opioids does not meaningfully improve discomfort
  These patterns differ from expected recovery or worsening of the original condition.

How a GP distinguishes OIH from other causes

Pain that worsens may relate to multiple factors — disease progression, tolerance, withdrawal, inflammation, nerve pain, or other medical issues. A GP carefully reviews your pain history, opioid dose and duration, pain pattern, and co-existing conditions. This helps differentiate OIH from other explanations and avoids simply increasing opioid doses when it is unlikely to help.

Managing suspected OIH

If OIH is considered likely, safe adjustments often involve gradually reducing or rotating opioids, or introducing non-opioid pain strategies. These may include multimodal pain relief such as acetaminophen, anti-inflammatory medicines, physical therapy, psychological support for coping strategies, and other interventions tailored to your situation. Stopping or tapering opioids should be done under GP guidance to avoid withdrawal symptoms and to maintain effective overall pain control.

Why open discussion with your GP matters

Persistent or worsening pain can be distressing and may have many causes. Discuss your experience openly with your GP, especially if pain feels different or more intense despite treatment. Your GP provides safe assessment, helps interpret patterns of pain, and supports a care plan that focuses on function, comfort, and quality of life.

Understanding when opioids help — and when they might contribute to increased pain — supports safer, more effective pain management.

This article provides general health information only and does not replace medical advice. Please speak with your GP for personalised care.