Parenteral treatments (either subcutaneous or intravenous) are frequently used in rheumatology practice. In this study, drug side effects in patients who were followed up with a rheumatic disease and treated with parenteral administration methods were evaluated. The drug side effects in children who were followed up with a rheumatic disease and treated with parenteral treatments between 2010 and 2019 were recorded, retrospectively. All parenteral treatments are applied by a clinical nurse specialist (CNS) who is experienced in pediatric rheumatology for 10 years. Four hundred and thirteen patients were evaluated in this study. The mean age was 12.09 ± 5.05 years. Most of them were diagnosed with juvenile idiopathic arthritis (n = 317) and colchicine-resistant familial Mediterranean fever (n = 57). Among the patients, 287 was treated with methotrexate, 130 with etanercept, 90 with adalimumab, 71 with anakinra, 64 with canakinumab, 55 with tocilizumab, seven with rituximab, six with infliximab, and four with abatacept. Two of the patients had a history of drug allergy (ceftriaxone = 1, ranitidine = 1). The most common adverse reactions were as follows: nausea-vomiting in 52, rash in 11, itching in three, chest tightening in two, bruising in two, headache in two, and abdominal pain in one of the patients. Drug side effects were observed after an average of three (1-4) administrations. Antihistaminic and steroids (tocilizumab = 3, infliximab = 1, methotrexate = 1) were administered to five patients due to hypersensitivity reactions. Considering the possible side effects and preparation protocols of parenteral treatments, experienced physicians and nurses are required in the field.