Aching joints, a headache that will not go away, or a fever.Common side effects include:Nausea, vomiting, or loss of appetite.Diarrhea.Itching or a rash.MethotrexateCall your doctor if you have:Hives.Signs of an infection, such as a sore throat, fever, sneezing, or coughing.Bloody vomit.Signs of unusual bleeding or bruising, such as black and tarry stools or blood in the urine.Diarr