Pharmacodynamics refers to the relationship between drug concentration at the site of action and the resulting effect, including the time course and intensity of therapeutic and adverse effects (Ashp.org, 2015). Folic acid is required as a one-carbon donator in the de novo synthesis of nucleoproteins and in maintaining sufficient erythropoiesis. Co-factors of folic acid in the form of tetrahydrofolate participate in transformation reactions, with one of these essential reactions producing deoxythymidine monophosphate (dTMP), one of three enzymes involved in the synthesis of thymidine, a nucleic acid of DNA. This reaction is achieved by thymidylate synthase catalyzing the transfer of the one-carbon unit of N5, N10-methylenetetrahydrofolate to
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Methotrexate can lower the concentration of folate in plasma, and thus may cause a megaloblastic anaemia. Other co-factors of tetrahydrofolate are responsible for metabolic reactions such amino acid interconversion (e.g., the conversion of homocysteine to methionine [a vitamin B12-dependent process] and the conversion of serine to glycine), histidine metabolism, formate generation and synthesis of essential purines. Folate molecules are highly hydrophilic, and thus tend to be transported actively across cell membranes rather than passively. Highly-specific transport systems utilizing folate receptors, the reduced folate carrier and the proton-coupled folate transporter mediate the passage of folates into the systemic tissues receptors. The anionic reduced folate carrier, which is found in all eukaryotic cells, delivers folates to systemic tissues at physiological pH (pH 7.4), whilst folate receptors transport folate via receptor-mediated at slightly acid and neutral pH (pH
Methotrexate can lower the concentration of folate in plasma, and thus may cause a megaloblastic anaemia. Other co-factors of tetrahydrofolate are responsible for metabolic reactions such amino acid interconversion (e.g., the conversion of homocysteine to methionine [a vitamin B12-dependent process] and the conversion of serine to glycine), histidine metabolism, formate generation and synthesis of essential purines. Folate molecules are highly hydrophilic, and thus tend to be transported actively across cell membranes rather than passively. Highly-specific transport systems utilizing folate receptors, the reduced folate carrier and the proton-coupled folate transporter mediate the passage of folates into the systemic tissues receptors. The anionic reduced folate carrier, which is found in all eukaryotic cells, delivers folates to systemic tissues at physiological pH (pH 7.4), whilst folate receptors transport folate via receptor-mediated at slightly acid and neutral pH (pH