Patients experiencing muscle pain and weakness as a result of statin treatment may continue to suffer symptoms long after stopping the drugs, French researchers reported.
Almost a third of patients who stopped statin treatment because of neuromuscular symptoms still showed myalgia six months later, and creatine kinase levels above 200 units/L persisted in 17%, according to Andoni Echaniz-Laguna, MD, PhD, of Hopitaux Universitaires in Strasbourg.
Writing in the Feb. 11 issue of the New England Journal of Medicine, researchers suggested that creatine kinase measurements at the start of statin therapy could help identify patients with underlying neuromuscular diseases.
Action Points
- Explain to interested patients that muscle pain and weakness are known side effects of statin therapy. In most patients, they resolve quickly when the drugs are stopped.
- Explain that this study reported on a small number of patients in whom symptoms persisted for six months after statins were discontinued. It did not address severity of symptoms, nor whether they eventually resolved.
For their study, Echaniz-Laguna and colleagues reported on 52 consecutive patients at their center who discontinued statin therapy as a result of muscle weakness and/or pain.
Creatine kinase levels were measured and myalgia assessed immediately on cessation of the drugs and again six months later. No data were available on creatine kinase levels when statins were begun.
About 40% of patients were taking simvastatin (Zocor), while 25% were on pravastatin (Pravachol) and 21% had taken atorvastatin (Lipitor), with other statins used in the remaining patients. Mean treatment duration was 30 months, with a range of six to 72 months.
The researchers indicated that no patients were taking other drugs that might increase the risk of statin-related myopathy.
Fifty of the 52 patients developed myalgia. Two reported muscle weakness. The mean creatine kinase level when treatment stopped was 1,000 units/L (range 300 to 6,000).
Echaniz-Laguna and colleagues determined that five of the patients had underlying neuromuscular diseases such as amyotrophic lateral sclerosis, paraneoplastic polymyositis, and muscle phosphorylase b kinase deficiency.
Those patients tended to be older, with a mean age of 67 (range 60 to 82), compared with 53 (range 22 to 86) among those with likely statin-related myotoxicity. The patients with underlying myopathies also were more likely to have muscle weakness and creatine kinase levels above 1,000 units/mL.
The researchers suggested that measuring creatine kinase might have identified the patients with underlying neuromuscular diseases before they started statin therapy.
Among those whose symptoms appeared related to statins, 11 of 36 patients available for follow-up at six months (31%) were still reporting muscle pain, and creatine kinase remained elevated in 17%.
Echaniz-Laguna and colleagues added that electromyography would be "an excellent screening test" in determining whether muscle biopsy is needed in patients with muscle symptoms while on statin therapy.
Patients with abnormal electromyographic findings also had pathologies in the biopsy studies, and negative electromyography results were confirmed in the biopsies, too.
Disclosures
No external funding for the work was reported.
Study authors declared they had no potential conflicts of interest.
Primary Source
New England Journal of Medicine
Echaniz-Laguna A, et al "Neuromuscular symptoms and elevated creatine kinase after statin withdrawal" N Eng J Med 2010; 564-65.