Designing medication therapies for FMS
I Jon Russell, M.D. PhD
Associate Professor of Medicine at The University of Texas Health Science Center at San Antonio
In many studies undertaken to determine the numbers of those who may have FMS it was shown that if you took any number of people 60% would be likely to be pain free, 30% would have some pain while the last 10% would loosely fit FMS criteria. Of that 10% only 20% would fully fit the criteria. There is a wide variation between pain that is purely chronic in nature and pain originating from FMS neurochemical dysfunctions.
An interesting incidental finding was that those who were aged 70 or over appeared to have a lot less pain or complained a lot less.
For doctors various means of assessment are available currently but the primary mode is to:
1: Confirm the general history and background.
2: Patient history/examination.
3. Identify any trigger/tender points being careful to properly determine each accurately.
4: Confirm the diagnosis of FMS in the absence of any other more serious rheumatology (or other) condition.
5: Identify any other comorbid conditions.
Primary FMS is singular with no other conditions associated with it.
Secondary is more common where there is more than 1 other comorbid condition either rheumatic (SLE, SJS, RA etc), infectious (Lyme disease) or endocrine (diabetes).
FMS causes chronic widespread allodynia and affects other aspects of pain modulation accordingly resulting in a very low pain threshold, temperature summation, abnormal neurochemistry and objective allodynia on more recent studies e.g. fMRI.
A physician’s role is always aiming towards gaining balanced nociception:
CSF biologic amines are low in the CFS of those with FMS. Nerve Growth Factor promotes Substance P production and again has been shown to be reduced in FSM.
Insomnia in FMS is more prevalent in the 30s. Interestingly it has been shown that the sleep patterns in those with FMS are very similar to those in the elderly and research is now assessing this to determine possible reasons. However, it has already been shown quite dramatically that there is accelerated gray matter loss in the brains of those with FMS causing premature aging of the brain cells. Gray matter neurons are important processing centres dealing with much of the daily cognitive requirements, hence it follows that this may indeed account for the high number of those with FMS who consider this to be an area of huge dysfunction for them. The rate of the loss is quite high and intriguingly if someone has chronic pain on one side of their body only it can account for a drop in brain matter on the opposite side of the brain.
PATHWAYS THROUGH FMS:
There is certainly a familial predisposition to the condition as shown by the chemical abnormalities, lower pain threshold, symptoms and social consequences within many families. In certain instances attempts have been made to repair systems by administration of NGF, however, this led to biological consequences with increased Subs P which led to further clinical consequences of pain, insomnia, fatigue and depression.
A possible management model thus may be the following:
A – Attitude of the physician and the patient – respect on both sides aiming towards a respectful working relationship to enable progression.
D – Always ensure there is no differential diagnosis of similar if not greater value – too many doctors provide a dx of FMS too quickly and once given rarely reassess despite further symptoms of concern.
E - Education for both doctor and patient including cognitive behavioural therapy for the patient.
P - Physical health – aim to enable the patient to recover some mode of fitness through home PT or other suitable exercise programmes.
T – Treatments – start with the least injurious/invasive and give time for a true assessment of usefulness. Stop within 6 weeks if not obviously efficacious. Ensure all drugs are tapered on and off slowly. Provide patient with a treatment plan and give them some responsibility for progression with it.
ADEPT – a model for as holistic an approach that can be made through the medical systems. Ensure that all of the above are followed up on regularly.
Of the various drug modalities available currently some stand out over others. Tramadol is very effective at reducing depression if used at appropriate dosages as it has an SSRI effect as well as analgesic. However, it requires to be carefully tapered upwards in dosing otherwise it can cause some difficult side effects such as nausea and severe headaches which tend to then put patients off dose increases.
Duloxetine (Cymbalta) is another newer and very important additive to the analgesic arsenal.
Pregabalin (Lyrica) is currently about one of the most efficacious drugs available and would normally be prescribed at doses ranging from 175 mg up to 400 mg max depending on weight. The first dose should be given at night, doubled at night and rarely provided during the daytime to prevent daytime somnolence.
Sodium oxybate (GHB and Xyrem) is now also proving highly effective for pain and sleep in particular as it increases growth hormone production which in turn impacts NGF production. It has also been shown to reduce the number and intensity of tender points.
Pain normally causes insomnia and/or depression – if a patient only suffers pain without depression then tramadol may help, but if they have two issues then Lyrica or duloxetine may prove more useful. And if they suffer all three problems then start with the SSRIs and add in the other drugs if necessary.