Why do my body feel numb after eating medicine?

My body feels slightly numb whenever I ate fedac (flu) and lysoyme (inflammation) why is this so? It has never happen to me before with other medicine and it's bothering me a little. For the first day when I ate it , it was really numb, especially when I go to sleep and wake up, the part where I place the hand under the pillow hurts a little. but it don't happen when I don't eat the pills,Why is that so, I go according to the prescription, and then lesser and it still hapens