Anaphylactic reaction to methotrexate

Hypersensitivity reaction to high-dose methotrexate and successful rechallenge in a pediatric patient with osteosarcoma

Hypersensitivity reactions to methotrexate are rare, but have been reported. Methotrexate has shown activity against many malignancies, and omission of methotrexate therapy may increase the risk of cancer-related death in some patients. Therefore, rechallenging patients with methotrexate following hypersensitivity may be beneficial. We report a case of a child with metastatic osteosarcoma who experienced a hypersensitivity reaction to high-dose methotrexate and was successfully rechallenged with methotrexate using a 6-hour infusion. Using this regimen, adequate peak methotrexate plasma concentrations were achieved and no further hypersensitivity reactions were noted.

Anaphylactoid reaction to high-dose methotrexate and successful desensitization

Anaphylactic/anaphylactoid reaction to methotrexate (MTX) is uncommon. It may occur with the first dose (non-allergic reactions) or after a previous exposure to the drug (allergic or specific reactions). Desensitization has been shown effective in children with allergic-type reactions permitting the continuation of high-dose methotrexate (HDMTX) therapy. We report the case of a child with localized osteosarcoma who developed an anaphylactoid reaction after a first HDMTX course. A desensitization protocol was successfully applied allowing the administration of four additional courses. In our experience, desensitization can be a safe and effective procedure in children with anaphylactoid reactions to HDMTX.

Delayed renal excretion of methotrexate after a severe anaphylactic reaction to methotrexate in a child with osteosarcoma

Although methotrexate is an agent widely used in the practice of pediatric oncology, allergic reactions to methotrexate are most unusual. Most of these reactions typically occur after repeated administration. Here, we report a severe anaphylactoid reaction to the first dose of high-dose methotrexate infusion in a child with osteosarcoma who has also experienced a delayed excretion of methotrexate. Clinicians must be aware of the possibility of a systemic, near-fatal anaphylactic reactions with methotrexate and patients who experience severe anaphylactic reactions should be followed carefully because of the possibility of delayed methotrexate excretion.

Management and successful desensitization in methotrexate-induced anaphylaxis

Anaphylactic/anaphylactoid reactions to methotrexate are rare. In patients with methotrexate-induced anaphylaxis, discontinuation of treatment may increase the risk of death due to cancer progression. In such patients, desensitization may enable the patient to continue treatment with methotrexate. We report the case of a child with metastatic osteosarcoma, who experienced an anaphylactic/anaphylactoid reaction to methotrexate. Skin tests with methotrexate were not performed because their diagnostic value is controversial. Desensitization with methotrexate was successful and allowed the patient to complete 12 additional courses of chemotherapy. Thus, we confirm that desensitization may be a safe procedure in patients with cancer who experience methotrexate-induced anaphylaxis.

Anaphylactoid reaction to high-dose methotrexate and re-administration after a successful desensitization

Methotrexate (MTX) is an antimetabolite with a major role in the treatment of acute lymphoblastic leukaemia (ALL). The authors report the management of a 9-year-old boy who developed an anaphylactoid reaction to high-dose MTX infusion, after a first challenge with intrathecal administration, during induction therapy for ALL. A desensitization protocol was followed and MTX tolerance has been successfully achieved, allowing this patient to complete the needed chemotherapy.

A Rare Drug Reaction to Methotrexate After Treatment for Ectopic Pregnancy

BACKGROUND

Ectopic pregnancies are commonly diagnosed and treated in physicians' offices. In the hemodynamically stable patient, therapy often includes treatment with methotrexate. Well-known adverse effects of this drug include mucositis, abdominal cramping, and malaise. We report a case of a rare drug reaction after treatment with methotrexate.

CASE

A 34-year-old, gravida 2, para 0, at 7 weeks of gestation by last menstrual period was diagnosed with an ectopic pregnancy and treated with methotrexate. The patient had an anaphylactoid reaction shortly after administration of methotrexate.

CONCLUSION

Methotrexate is a commonly used therapy for ectopic pregnancies in the outpatient setting. Practitioners should be aware of the potential adverse reactions to methotrexate.