Are Trump's problems with walking, drinking water due to hydroxychloroquine?

Physicians have rightly been concerned about the cardiac effects of this medication on the heart’s rhythm. But hydroxychloroquine has some other, less frequently cited adverse effects. If you read the FDA required package insert under adverse effects, here is what you will find:

“Musculoskeletal and connective tissue disorders: Sensorimotor disorder, skeletal muscle myopathy or neuromyopathy leading to progressive weakness and atrophy of proximal muscle groups, depression of tendon reflexes and abnormal nerve conduction.” [Emphasis added]

Proximal muscles are those closest to our body, like the muscles of the upper arm that raise the arm and hand. Or the muscles of the thigh that are actively involved in all phases of walking. It is not an overly common adverse side effect. It is probably relatively rare, but a quick search uncovered a review of 10 cases of hydroxychloroquine associated neuromyopathy.