Psychiatry
A 2015 Cochrane review found no evidence of benefit in anxiety disorders as of 2015. Another review found preliminary evidence of benefit. Evidence for use in addiction is tentative but also unclear. Mechanism of action
Cycloserine works as an antibiotic by inhibiting cell-wall biosynthesis in bacteria. As a cyclic analogue of D-alanine, cycloserine acts against two crucial enzymes important in the cytosolic stages of peptidoglycan synthesis: alanine racemase (Alr) and D-alanine:D-alanine ligase (Ddl). The first enzyme is a pyridoxal 5-phosphate-dependent enzyme which converts the L-alanine to the D-alanine form. The second enzyme is involved in joining two of these D-alanine residues together by catalyzing the formation of the ATP-dependent D-alanine-D-alanine dipeptide bond between the resulting D-alanine molecules. If both of these enzymes are inhibited, then D-alanine residues cannot form and previously formed D-alanine molecules cannot be joined together. This effectively leads to inhibition of peptidoglycan synthesis. Chemical properties
Under mildly acidic conditions, cycloserine hydrolyzes to give hydroxylamine and D-serine. Cycloserine can be conceptualized as a cyclized version of serine, with an oxidative loss of dihydrogen to form the nitrogen-oxygen bond.Cycloserine is stable under basic conditions, with the greatest stability at pH = 11.5. History
The compound was first isolated nearly simultaneously by two teams. Workers at Merck isolated the compound, which they called oxamycin, from a species of Streptomyces. The same team prepared the molecule synthetically. Workers at Eli Lilly isolated the compound from strains of Streptomyces orchidaceus. It was shown to hydrolyze to serine and hydroxylamine.
The combination drug acetylsalicylic acid/dipyridamole (trade names Aggrenox, Asasantin) is a drug combination of:
Acetylsalicylic acid (Aspirin) - An extremely common NSAID that has anticoagulant effects
Dipyridamole, a drug that inhibits platelet activation when given chronically and causes vasodilation when given at high doses over short time.The combination acts as an extended release formulation and is primarily used for platelet inhibition in patients suffering, or at risk from, acute coronary events and stroke. Its use has been shown to be better than the use of either dipyridamole or aspirin alone. == References ==