Amitriptyline and nortriptyline are similar medications that your pain team may recommend you consider taking for pain management. These medications were initially designed to treat depression and anxiety. However, there are now more specific medications for those conditions; instead, we use these medications to help manage your pain.
Your brain has many neurotransmitters (messaging chemicals) that work on the nerves within your brain – these medications were initially designed to normalise those to reduce depression and anxiety. However, it was found that many people who took these medications improved their pains. These medications reducing pain makes sense, as the same neurotransmitters in our brain are also the ones that can send pain signals.
If you have experienced pain for more than 12 weeks, we call this chronic pain. We know that for people with chronic pain, these neurotransmitters change and they adapt to get ‘better’ at giving you pain. We call this process sensitisation.
Sometimes, the pain you experience stops you from doing what you want to do and participating in rehabilitation and exercises to help heal your body. Amitriptyline and nortriptyline work to try and normalise these neurotransmitters back to normal levels, reduce sensitisation, and ultimately reduce your pain to allow you to participate in rehabilitation.
Unfortunately, there is no way to know in advance if these medications will help your specific type of pain. No blood tests or imaging can tell us if your neurotransmitters are misfiring in a way that these medications may be able to help. The only way is to initially trial these medications at low doses, then up the required amount to try and reduce your pain. We know that if we give these medications to 3.5 people, 1 of those people will have a reduction in their pain of >50%. Others may experience less relief or no relief.
Some people will experience side effects, and the medication will need to bechanged or stopped. We cannot predict who may have side effects but we always start at low doses, so it is easier to cease if the medication does not suit you. The most common side effects of amitriptyline include dry mouth, mild constipation, and sleepiness.
Sometimes these side effects wear off over a week or two. In rare circumstances, people may gain 2-3 kg of weight (though everyone is different – some people can even lose weight). Nortriptyline is a cousin of amitriptyline, and we do not have as much research on nortriptyline on pain. However, it works similarly and is less likely to cause the above side effects, but it is still expected to be helpful for pain.
If you have further questions or want more information, talk to your pain team, your GP, or your pharmacist.