Doctor says that simvastatin should be considered among the causes of peripheral neuropathy

This study was published in the Journal of Neurology, Neurosurgery and Psychiatry 1995 May;58(5):625-8

Study title and authors:
Peripheral neuropathy associated with simvastatin.

Phan T, McLeod JG, Pollard JD, Peiris O, Rohan A, Halpern JP.
Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Australia.

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/7745415

This paper describes four patients who developed sensorimotor neuropathy (sensorimotor neuropathy is a type of peripheral neuropathy that damages the motor nerves and the sensory nerves) while being treated with simvastatin and had complete or partial recovery after the withdrawal of statin treatment.

Case 1
A man aged 52 started treatment with simvastatin (10 mg/day).

Soon after he noticed generalised muscle weakness and fatigue. The weakness became progressively worse and he had difficulty in ascending stairs and running. After six months his right foot and subsequently his left foot became numb.

Treatment with simvastatin was withdrawn and on review six weeks later muscle cramps and weakness had improved although he still had the symptoms and signs of peripheral neuropathy.

On his last review, 18 months after the withdrawal of simvastatin, there had been furter clinical improvement.

Case 2
A women of 66 had started two years previously with simvastatin (10 mg/daily) which was subsequently gradually increased to 40 mg/daily after one year.

After the two years of statins the woman had weakness of the lower limbs and difficulty in rising from a chair. After three more months she was severely incapacitated and confined to a wheelchair. By four months she was unable to feed herself or to comb her hair and was admitted to a nursing home. She had pain in the fingers, the front of her legs, lower chest and abdominal wall.

Simvastatin was stopped and improvement followed. Nine months later she could feed herself, comb her hair and walk with the aid of a stick. Power in all muscle groups in the lower limbs also increased greatly.

Case 3
A women of 65 had started two years previously with simvastatin (10 mg/daily) which was subsequently increased to 20 mg/daily after one year.

After two years of statins the woman developed upper and lower limb weakness. Initially she had difficulty in rising out of chairs and climbing stairs and weakness progressed over a period of six weeks untill she was unable to lift her arms above her head, rise from a chair unaided, or walk without support. She complained of a burning sensation in her left foot.

Simvastatin treatment was withdrawn and four months later she had completely recovered clinically.

Case 4
A women ages 39 was given a daily dose of 10 mg of simvastatin.

Within 24 hours of starting the drug she developed pain in her right calf, and later pain in her right groin and pains down both arms. These symptoms were followed by the development of a sensation of pins and needles in her fingertips and later the toes.

Simvastatin was discontinued after a total dose of 180 mg. On review three months later she reported almost complete recovery from her symptoms except for a few patches of tenderness over her body.

Conclusion

The researchers suggest that statins may damage the peripheral nerves because they block the production of ubiquinone (Coenzyme Q10). Without the presence of ubiquinone within the body’s cells, cellular energy cannot be generated or sustained.

The head of the study, Dr Tai Phan, concluded that: "Simvastatin should be considered among the causes of peripheral neuropathy".