You have given the age of the patient as 2 (two) years and weight of 17 kg. For fever at 38.3 degree C, only paracetamol should be more than adequate that too as and when required i.e. if the temperature goes above 38 degree. There is no need to give paracetamol every 4 hours (which actually means 6 times a day). One should use the normal paediatric suspension (Calpol) that contains 125 mg, per ml (and never double strength suspension that contains 250 mg, per 5 ml so as to avoid overdose). The dose of paracetamol for a two year old should be 8 ml of low-dose suspension as and when required. Generally 2-3 times a day is adequate. No need to give ibuprofen in addition to paracetamol. Such a combination in such a high dose may have adverse effect on the liver.