Asthma methotrexate

Folic Acid Antagonists. Folic acid antagonists block the biosynthesis of purine nucleotides. Methotrexate (7.76) is the prototypic fohc acid antagonist and functions by binding to the active catalytic site of dihydrofolate reductase, thereby interfering with the synthesis of the reduced form that accepts one-carbon units lack of this cofactor blocks the synthesis of purine nucleotides. As well as being used in the treatment of cancer, methotrexate has been used in the management of rheumatoid arthritis, psoriasis, and even asthma. 

An older patient with rheumatoid arthritis died after receiving an overdose of methotrexate—a 10-milligram daily dose of the drug rather than the intended 10-milligram weekly dose. Some dosing mix-ups have occurred because daily dosing of methotrexate is typically used to treat people with cancer, while low weekly doses of the drug have been prescribed for other conditions, such as arthritis, asthma, and inflammatory bowel disease. 

Anakinra is the first IL-1 Ra to be approved for use in adults with moderate to severe active rheumatoid arthritis who have not responded adequately to conventional DMARD therapy. It may be used either alone or in combination with methotrexate. Anakinra Is supplied in single-use, prefilled, glass syringes as sterile, clear, preservative-free solution that is administered daily as a self-administered subcutaneous injection under the skin. Some potential side effects include injection site reactions, decreased white blood cell counts, headache, and an increase in upper respiratory infections. There may be a slightly higher rate of respiratory infections in people who have asthma or chronic obstructive pulmonary disease. Persons with an active infection are advised not to use anakinra. Its elimination half-life after sc administration is 4 to 6 hours. 

The apparent elearanee of theophylline (given as oral aminophylline, eholine theophyllinate or theophylline) was reduced by 19% in 8 patients with severe, steroid-dependent asthma after 6 weeks of treatment with in-tramuseular methotrexate 15 mg weekly. Three patients complained of nausea and the theophylline dosage was reduced in one of them as the theophylline level was more than 20 mierograms/mL. ... 

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