Since FMS is a condition characterized by central sensitization (nervous system hypersensitivity), it is therefore most appropriate to go for neuropathic (nerve pain) medication that may have the best chance of controlling symptoms.
General simple analgesics can be given first such as paracetamol and various strengths of codeine, taken individually or in combination.
NSAIDs (Non steroidal Anti-inflammatory drugs)can be tried if there are local muscular components where the pain is worse.
Tramadol may also be considered in some patients but it has its share of side effects and is not very well tolerated by a lots of patients..
Opioids, especially strong opioids such as morphine, are not recommended without specialist advice and support.
Corticosteroids were also recommended against because of lack of significant benefit and risk of significant side effects.
There is some evidence for the use of antiepileptics such as pregabalin and gabapentin. Pregabalin has been more extensively studied and the quality of evidence is good but side effects profile is high.
Amitryptiline is an old-school drug belonging to the tricyclic group and has been extensively studied in a variety of neuropathic pain conditions.
Fluoxetine/ duloxetine and more recently milnaciparan(not available in the UK as yet) are another group of antidepressants which have been tried in fibromyalgia with some effect but again there is no benefit that it will help in the long term.
However some medications which work well for one patient may not be successful in another. Therefore it is important that medication choices are discussed with your GP or your specialist. There is also the possibility that some drugs may not even be available for being prescribed locally by your GP.
At the Royal Berkshire Hospital, we have prepared a handy list of pain medication that we prescribe and recommend to the GP and you can download it here