Magnesium salicylate is a common analgesic and nonsteroidal anti-inflammatory drug (NSAID) used to treat mild to moderate musculoskeletal pain such as in tendons and muscles. It is also used to treat joint pain like arthritis, general back pain, and headaches.It is found in a variety of over-the-counter (OTC) medications, most notably the brand Doans Pills, as an anti-inflammatory, primarily for back-pain relief. Magnesium salicylate can be an effective OTC alternative to prescription NSAIDs, with both anti-inflammatory and pain-relieving effects. Controversy
While magnesium salicylate is sold as an alternative for pain relief, it is still a nonsteroidal anti-inflammatory drug and, like others in this class, can cause stomach ulcers,  without any proven superiority to other over-the-counter pain relievers. Novartis, the company (formerly known as Ciba or Ciba-Geigy Corp.) that produces Doans Pills, has claimed that the product is superior in providing back pain relief. In June 1996, the US Federal Trade Commission (FTC) charged the company with violating federal law with its unsubstantiated claim. In March 1998, the court ruled in favor of the FTC, but there was no stipulation about how the company should or would have to amend its advertising/packaging. Thus, Doans was able to continue marketing as a "superior treatment for back pain".
Myokymia is an involuntary, spontaneous, localized quivering of a few muscles, or bundles within a muscle, but which are insufficient to move a joint. One type is superior oblique myokymia. Myokymia is commonly used to describe an involuntary eyelid muscle contraction, typically involving the lower eyelid or less often the upper eyelid. It occurs in normal individuals and typically starts and disappears spontaneously. However, it can sometimes last up to three weeks. Since the condition typically resolves itself, medical professionals do not consider it to be serious or a cause for concern. In contrast, facial myokymia is a fine rippling of muscles on one side of the face and may reflect an underlying tumor in the brainstem (typically a brainstem glioma), loss of myelin in the brainstem (associated with multiple sclerosis) or in the recovery stage of Miller-Fisher syndrome, a variant of Guillain–Barré syndrome, an inflammatory polyneuropathy that may affect the facial nerve.Myokymia in otherwise unrelated body parts may occur in neuromyotonia. Causes
Frequent contributing factors include: too much caffeine, high levels of anxiety, fatigue, dehydration, stress, overwork, and a lack of sleep. Use of certain drugs or alcohol may also be factors, as can magnesium deficiency. It can be also seen in patients with multiple sclerosis.