Hello I'm new to the forum. I've had asthma for more years than I care to remember. In recent years it has been managed by taking a preventer everyday along with a reliever, prednisolone and antibiotics when bad. Now at 65 I've had a cough and breathlessness that never goes away so have been prescribed slo-phyllin. After two days of taking it I've hardly slept due to a fizzing feeling all over, a headache so intense I could hardly get my head off the pillow and a strong pain in my left leg, along with heartburn, and feeling sick. My blood levels haven't been checked. I was hoping to feel better for a flight to the US in a weeks time but have concerns now whether to continue with it in the hope these symptoms will go! I would welcome any thoughts or advice.