Pain: patient summary

Now you’ve heard from the team about the science of morphine. Let’s think about how this information is relevant to Ari, our patient with chronic back pain. You’ve heard how the interaction of morphine with its receptor relies on its rigid structure, and how the binding of morphine to neuroceptors provides pain relief. You’ve also heard that morphine itself has quite a short half life, but it is formulated to be slow release, allowing it to be taken twice daily for long acting pain relief. Morphine has a lot of side effects and is one of the last medications used for pain relief when other medication has failed to control pain.

Many side effects occur because neuroceptors are found in the brain stem, where multiple physiological functions are regulated. These side effects include reduced rate of breathing, which is the leading cause of death from morphine, nausea and vomiting, which affects up to 40% of patients, severe constipation, drowsiness, and cough suppression. Morphine, and similar medicines, can cause significant tolerance. Tolerance is the gradual decrease in effectiveness when a drug is given repeatedly over a sustained time. So when tolerance occurs, a larger dose is required for the patient to have the same effect. Tolerance can develop to the analgesic effects of morphine, but also to the side effects, such as sedation, nausea, and vomiting.

On talking to Ari, he may not be managing his pain in the best way. You may remember from the introduction that Ari is taking a number of different medications to help manage his back pain. It is concerning that he’s taking two opiates, both morphine and codeine, and two non-steroidal anti-inflammatory drugs, diclofenac and ibuprofen. Ideally, Ari should not be taking morphine at all, or at least only using it sometimes when the pain is severe and not controlled by other measures. One possible alternative for him to manage his pain relief is to use regular paracetamol and take an anti-inflammatory medication, only one, when needed. That is, he would only take morphine as a last resort.

And given morphine’s common side effect of drowsiness, it may be better for Ari to only take morphine at night so it doesn’t make him sleepy during the day, especially if he’s driving.