It appears that you have suffered from statin induced myopathy secondary to your simvastatin. Statins are commonly prescribed to to treat hypercholesterolemia (high cholesterol) and have a relatively low rate of side effects. The most common side effects are muscle myopathies which range from an asymptomatic rise in creatine phosphokinase (a byproduct of muscle breakdown) to mild myalgia (muscle pain) to rhabdomyalysis (rapid, fulminant muscle breakdown). Muscular side effects can be expected in 10 to 15% of statin users.
The prognosis varies depending on the condition: a patient who has suffered statin induced rhabdomyalysis – a rapid, fulminant destruction of muscle tissue – will have a much longer recovery time than a patient suffering from statin induced myalgia. Diagnosis of rhabdomyalsis includes an elevation in creatine phosphokinase, elevation in potassium, deterioration of kidney function, dark urine, as well as extreme weakness and muscle pain. From what you are describing, it appears that you have a statin induced myalgia. The overall prognosis of this condition is extremely favorable as long as it is recognized and treated promptly.
The first line of treatment is to discontinue the statin. Secondly, adequate hydration must be maintained to prevent any kidney damage. Recent trials have shown vitamin D therapy, for those deficient in vitamin D, to be effective in treating and aiding recovery from statin induced myopathy. There have been clinical trials of coenzyme Q10 supplementation in patients with statin myopathy but the results have been inconcusive and there is no evidence to support its use to treat statin induced myopathy.
In my experience, elderly patients who have had statin induced myopathy take anywhere from 3 months to over a year after stopping statins to recover from the muscle aches. The most important factor in these patient’s recovery is to resume as much of their daily activities and exercise as they can tolerate. Bedrest is not advised, especially in the elderly, as it will deteriorate their muscles even further and further compromise their strength.