My 4-month old son was recently prescribed oral drops with pseudoephedrine hydrochloride as the main ingredient. Soon after, approximiately two days later his head and arms started shaking uncontrollably as if he was having a seizure. I took him back to the doctor who suggested I stop giving him this medication, which I had already done the day before. He is still having episodes of seizure-like symptoms even after being off this medication for four days.