Updates on Diagnosis and Clinical Management of Fibromyalgia

Approved Treatments

For most patients with fibromyalgia, pharmacologic manage­ment aims to reduce symptoms such as pain and improve quality-of-life. The FDA has approved 3 medications for the treatment of fibromyalgia: pregabalin, duloxetine, and milnacipran (Table).¹²

Pregabalin, approved by the FDA for the treatment of fibro­myalgia in 2007, is an anticonvulsant and analgesic that works by binding to the α-2-Δ subunit of voltage-gated calcium channels in the central nervous system.¹¹ The usual starting dose is 75 mg twice daily, titrated up to 225 mg twice daily. Patients taking pregabalin should have complete metabolic panels checked regularly to monitor creatinine clearance.¹

Duloxetine and milnacipran, approved in 2008 and 2009, respectively, are serotonin and norepinephrine reuptake inhibitor agents.¹¹ These drugs alter levels and function of neurotransmitters and address the anxiety and depression that often affect patients with fibromyalgia.⁵ The usual starting dose of duloxetine is 30 mg once daily, titrated to 60 mg after 1 week. Milnacipran usually is started at 12.5 mg daily and titrated to 50 mg twice daily.¹²

Off-Label Treatments

Although not approved by the FDA for this indication, the tricyclic antidepressant amitriptyline is the most common off-label medication prescribed to treat fibromyalgia. Patients generally are prescribed 25 to 50 mg of amitriptyline daily and report an improvement in pain, sleep disturbance, and fatigue. Reported adverse reactions include dry mouth, somnolence, gastrointestinal disturbances, and weight gain, which may limit the drug’s rate of titration.¹¹

Cyclobenzaprine is a muscle relaxant that also is used for the management of fibromyalgia symptoms including pain and sleep disturbances. However, many patients report adverse effects, including drowsiness, dry mouth, fatigue, dizziness, nausea, and heartburn.^11,12

Tramadol, a synthetic opioid receptor agonist, is considered by some to be an alternative option that offers additional analgesic effects through enhanced serotonin release and inhibition of norepinephrine reuptake.^5,11

Despite some evidence showing their efficacy, nonsteroidal anti-inflammatory drugs seldom are used in combination with antidepressants or anticonvulsants because they may suppress the antidepressant action of these agents.¹¹

When deciding on which agents to prescribe to treat fibromy­algia, clinicians should consider patient preferences, risk factors, and comorbidities. If medications are prescribed, they should be started at low doses and prudently titrated as needed. Patients who do not report an improvement in their fibromyalgia symptoms or are unable to tolerate adverse effects are advised to discon­tinue these medications and consider alternative therapies.^5,10-12

Summary

Fibromyalgia is a chronic pain condition characterized by wide­spread musculoskeletal pain, sleep disturbance, fatigue, and func­tional impairment. To optimize care of this complex condition, health care practitioners should work with patients to develop individualized management plans tailored to their symptoms.

References

1. American College of Rheumatology. Fibromyalgia. https://www. rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/ Fibromyalgia. Accessed August 3, 2020.
2. Stewart JA, Mailler-Burch S, Muller D, et al.  Rethinking the criteria for fibromyalgia in 2019: the ABC indicators.  J Pain Res. 2019;12:2115-2124.
3. Wolfe F, Clauw DJ, Fitzcharles MA, et al. Fibromyalgia criteria and severity scales for clinical and epidemiological studies: a modification of the ACR preliminary diagnostic criteria for fibromyalgia. J Rheumatol. 2011;38(6):1113–1122.
4. Wolfe F, Clauw DJ, Fitzcharles MA, et al.  2016 Revisions to the 2010/2011 fibromyalgia diagnostic criteria.  Seminar Arthritis Rheum.  2016;46(3):319-329.
5. Rahman A, Underwood M, Carnes D.  Fibromyalgia. BMJ. 2014;348:g2870.
6. Weir P, Halan GA, Nkoy FL, Jones SS, et al. The incidence of fibromyalgia and its associated comorbidities: a population-based retrospective cohort study based on International Classification of Diseases, 9th Revision codes.  J Clin Rheumatol. 2006;12(3):124-128.
7. Abeles A, Pillinger MH, Solitar BM, Abeles M. Narrative review: the pathophysiology of fibromyalgia.  Ann Intern Med. 2007;146(10):726-734.
8. Price DD, Staud R.  Neurobiology of fibromyalgia syndrome.  J Rheumatol Suppl. 2005;75: 22-28.
9. International Association for the Study of Pain (IASP). IASP Council adopts task force recommendation for third mechanistic descriptor of pain. November 14, 2017. https://www.iasp-pain.org/PublicationsNews/NewsDetail.aspx?ItemNumber=6862. Accessed August 3, 2020.
10. Kwiatek R. Treatment of fibromyalgia. Aust Prescr. 2017;40(5):179-183.
11. Thomas SA, Knight L, Balian A. Treatment of fibromyalgia pain. US Pharm. 2016;41(3):51-54
12. Arnold LM, Clauw DJ, Dunegan LJ, Turk, DC, FibroCollaborative.  A framework for fibromyalgia management for primary care providers. Mayo Clin Proc. 2012;87(5):488-496.

This article originally appeared on Clinical Advisor

From the September 2020 Issue of Rheumatology Advisor