What is the brand name of methotrexate?

A. Flexeril is the brand name for cyclobenzaprine hydrochloride, a skeletal muscle relaxant. It acts on the locus coeruleus to reduce tonic somatic motor activity. It does not possess the antimetabolite properties characteristic of the drug methotrexate specified in the question. B. Xalatan is the brand name for latanoprost, a prostaglandin F2-alpha analog used in ophthalmology. It increases uveoscleral outflow to reduce intraocular pressure. It is not chemically or therapeutically related to the folic acid antagonist methotrexate mentioned in the question stem. C. Trexall is a proprietary brand name for methotrexate, an antimetabolite and antifolate agent. It competitively inhibits dihydrofolate reductase, preventing the conversion of dihydrofolate to tetrahydrofolate. This action disrupts DNA synthesis and cellular replication in neoplastic and inflammatory cells. D. Zanaflex is the brand name for tizanidine, a central alpha-2 adrenergic agonist used for spasticity. It increases presynaptic inhibition of motor neurons to reduce muscle tone. It lacks the immunosuppressive and cytotoxic mechanisms of action that define the molecule methotrexate.