Others visual disturbances may occur very rarely in patients who received higher doses than recommended. • Muscle and joint disorders - joint, muscle and bone pain, leg cramps and abnormal weakness of certain muscles (myasthenia). • Nerve disorders - numbness and tingling of your skin (which resolved in about 40 to 60% of patients), tiredness, dizziness, nervousness, depression, abnormal thoughts, insomnia, reduced mobility (hypokinesia), reduced sensory perception (hypaesthesia), gait disorders, altered taste and headache.