The most common adverse effects include: hepatotoxicity (liver damage), ulcerative stomatitis, leukopenia and thus predisposition to infection, nausea, abdominal pain, fatigue, fever, dizziness, acute pneumonitis, rarely pulmonary fibrosis, and kidney failure.<unk>  is teratogenic and hence is not advised for either the prospective father to take it before or for the mother to take it before or during pregnancy (pregnancy category X) and for a period after birth.<unk>  can also cause mucositis. Central nervous system reactions to<unk>  have been reported, especially when given via the intrathecal route (directly into the cerebrospinal fluid), which include myelopathies and leukoencephalopathies. It has a variety of cutaneous side effects, particularly when administered in high doses. Another little understood but serious possible adverse effect of<unk>  is neurological damage and memory loss. Neurotoxicity may result from the drug crossing the blood–brain barrier and damaging neurons in the cerebral cortex. People with cancer who receive the medication often nickname these effects "chemo brain" or "chemo fog". Drug interactions Penicillins may decrease the elimination of<unk> , so increase the risk of toxicity. While they may be used together, increased monitoring is recommended. The aminoglycosides, neomycin and paromomycin, have been found to reduce gastrointestinal (GI) absorption of<unk> . Probenecid inhibits<unk>  excretion, which increases the risk of<unk>  toxicity. Likewise, retinoids and trimethoprim have been known to interact with<unk>  to produce additive hepatotoxicity and haematotoxicity, respectively. Other immunosuppressants like cyclosporins may potentiate<unk> 's haematologic effects, hence potentially leading to toxicity. NSAIDs have also been found to fatally interact with<unk>  in numerous case reports. Nitrous oxide potentiating the haematological toxicity of<unk>  has also been documented. Proton-pump inhibitors such as omeprazole and the anticonvulsant valproate have been found to increase the plasma concentrations of<unk> , as have nephrotoxic agents such as cisplatin, the GI drug colestyramine, and dantrolene.
Methotrexate
Phototrexate
Cyclophosphamide
Azathioprine
Lenalidomide
Etanercept
Prednisolone
Thalidomide