Antidepressants in the treatment of pain

By 14 January 2016articles
Antidepressants in the treatment of pain

Antidepressant medications have long been used in the treatment of pain. Naturally, the original medications were designed to treat depression. They achieve this by increasing the amount of Serotonin and Noradrenalin in the nerve pathways that control mood. These two chemicals are ‘transmitters’ that send messages from one nerve to another.

Latterly as our understanding of pain pathways developed it was apparent that Serotonin and Noradrenalin levels are also important in the transmission and modulation of pain messages. As a consequence antidepressants became increasingly used in the treatment of pain.

As far back as the late 1960s an antidepressant medication called Amitriptyline was identified as a powerful pain-killer. In particular this medication and others subsequently developed are very helpful in treating ‘neuropathic pain’. This type of pain occurs where nerves have been damaged either by direct trauma or by other disease processes such as Diabetes or poor circulation. Indeed Amitriptyline is the number one choice for treating Shingles pain. Its immediate use reduces the acute pain and lessens the chance of patients suffering this awful condition from developing a long term pain syndrome called Post Herpetic Neuralgia, which is very incapacitating and difficult to treat.

Sadly, there is often a stigma attached to using antidepressants. A significant number of patients are unwilling to try such medications as they feel that their doctor assumes that there pain is imaginary… it’s ‘all in your head’. This is simply not the case. These medications are very commonly used for pain when there is no sign of depression at all. This is a really important point to understand. Prescribing antidepressants is not a way of dismissing the problem.

How to use antidepressants

These medications need to be taken regularly. The dose of the medication should be small to begin with and gradually increased in case side-effects occur (see below). The medication is often taken before bed at night as some patients find that it makes them sleepy. Of course if the pain is causing sleep disturbance, this can be a very positive benefit. It takes days and sometimes several weeks for the full benefits to become apparent. Therefore it is important to persevere and give the medication time.

The antidepressant needs to be maintained for weeks and months till the problem causing the pain subsides, or more permanent solutions can be found. When discontinuing the medication, it is wise to reduce the dose over several weeks, to make sure that the underlying pain has settled. It is uncommon, but some patients suffer a with-drawl phenomenon when stopping such medications and so a slow reduction in dose is again wise.

Side-effects

You should always read the information leaflet that comes with the medication. Often the list, as with ALL medications, can be quite daunting. The pharmaceutical company that makes the product is obliged to record any negative effect however uncommon. If these problems develop for you soon after taking the antidepressant, then it is wise to discontinue its use and contact the person who prescribed it.

If you are taking any other regular medications, you should check with your doctor or pharmacist that the combination is safe.

Most patients do tolerate antidepressants very well.

Mild side-effects

  • Dry mouth
  • Sleepiness
  • Nausea
  • Constipation

Severe side-effects (uncommon)

  • Confusion / disorientation
  • Blurred vision
  • Difficulty passing urine
  • Irregular heart beat

This is not a comprehensive list. These medications should be avoided when breast feeding.

The role of antidepressants in treating pain

These medications are principally used when abnormal nerve function or damage is generating the pain. They can be used on their own or in combination with other sorts of pain-killers such as Paracetamol or Codeine and many others. There are many examples where antidepressants have a role to play:

  • Many patients who have an incision for an operation find that the scar can be sensitive long after it has healed. This is particularly common after breast surgery.
    Patients suffering from Diabetes can develop a ‘painful neuropathy’. The Diabetes damages the small nerve endings in the feet and hands. They often complain of a burning sensation.
  • Pain from the gut. It is interesting that after the brain, the organ containing the largest umber of nerves is the intestine. Complicated networks of nerves are required for the gut to perform its complex role in digestion. When the gut has become inflamed or damaged, often antidepressants can be helpful.
  • Headache. There are many causes of headache. Most are tension headaches from tightness of muscles in the scalp. These respond to anti-inflammatory medications or muscle relaxing drugs. However, antidepressants can help with more atypical persistent headaches.

These are just a few examples, there are many more.

Other indications for antidepressants

Of course the commonest use for antidepressants is indeed depression. Depression is often as a consequence of unhappy personal circumstances; however it can sometimes develop unexpectedly with no apparent obvious cause.

When patients are suffering from pain, particularly if it has been persisting for weeks and months, it is little wonder that their mood becomes affected. The incapacity that pain brings, coupled with sleep disturbance is a combination that is increasingly difficult to cope with. Anger, frustration, mood swings and feeling miserable are hardly surprising.

There is a link between pain and depressed mood. If pain is severe then the patient’s mood suffers. If depression is present then being able to cope with the pain becomes increasingly difficult and the knock-on effects are all the greater. This is a cycle where pain and depression feed off each other and a downward spiral can result.

When an antidepressant is prescribed in these circumstances and the patient gains benefit, it is hard to know whether the medication is directly treating the pain, relieving the depression or both. In reality it does not matter, as long as the pain and mood both improve.

Summary

  • Antidepressants a re a powerful tool in treating pain.
  • There are many situations where antidepressants can be helpful.
  • Caution should be employed when starting and stopping the medication.
  • Prescribing antidepressants is not a way of ‘dismissing the pain’ as imaginary.
  • If understandable mood changes occur as a consequence of the pain, then such medications are doubly important so that patients can cope with the situation, till a better solution is found.