Drug Interactions between Bactrim and niraparib

Using niraparib together with sulfamethoxazole may have additive effects on the immune system, possibly increasing the risk of low blood cell counts (e.G., red blood cells, white blood cells, platelets) and infections. Less commonly, the risk of more serious side effects known as myelodysplastic syndrome or acute myeloid leukemia could increase. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. Let your doctor know if you experience pale skin, weakness, fatigue, fever, weight loss, infections, shortness of breath, unusual bleeding or bruising, or blood in urine or stool. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.