What Causes Excessive Sleepiness And Fatigue After Stopping Lyrica?

hi. My husbands doctor recently doubled his Lyrica from 75mg once a day to twice. Don is 84, has advanced diabetes with restless legs. Lyrica was prescribed for leg pain a few years ago. He went from almost normal to hallucinations, extreme drowsiness, confusion, blurred vision and abnormal gait after just the second double dose. It was extremely scary. Saw the nurse practitioner who said it could take a Week to get over. He s not taken any Lyrica since. It s been a week. No more hallucinations. His co fusion has stopped, but he s sleeping most of the time and is extremely slow to respond. Walking at a snails pace and falling asleep at the drop of a hat. Any thoughts? Thank you My question is. How lo g could these side effects last