Diffuse Muscle Weakness

Okay. There are a number of reasons that these muscles may become weak. Certain medications can do it, and that's one of the most common causes. While there's a long list of medications that occasionally cause muscle weakness, the most common are corticosteroids (such as prednisone), statin-type cholesterol-lowering medicines (such as lovastatin, simvastatin or atorvastatin), and the anti-HIV drug, AZT (also called zidovudine or azidothymidine).

Have you started any new medications lately? Are you taking a corticosteroid medication, a statin, or AZT?

Yes, I take one of those or just started a new medicine.

Nope, no new medicines and none of those you mention.