Cycloserine, sold under the brand name Seromycin, is a GABA transaminase inhibitor and an antibiotic, used to treat tuberculosis.

[2] Common side effects include allergic reactions, seizures, sleepiness, unsteadiness, and numbness.

[2] Cycloserine is similar in structure to the amino acid D-alanine and works by interfering with the formation of the bacteria's cell wall.

Another reason for limited use of this drug is the neurological side effects it causes, since it is able to penetrate into the central nervous system (CNS) and cause headaches, drowsiness, depression, dizziness, vertigo, confusion, paresthesias, dysarthria, hyperirritability, psychosis, convulsions, and shaking (tremors).

[6] Coadministration of pyridoxine can reduce the incidence of some of these CNS side effects (e.g. convulsions) caused by cycloserine.

[11] Psychiatric use is suggested based on partial NMDA receptor agonism, which improves neural plasticity in lab animals.

[12][13] Cycloserine can be conceptualized as a cyclized version of serine, with an oxidative loss of dihydrogen to form the nitrogen-oxygen bond.

[12] Initial approaches to synthesize the compound was first published in 1955, when the Stammer group produced a racemic synthesis from DL‐β‐aminoxyalanine ethyl ester.

Chemical synthesis of the compound was revolutionized in the 2010s, when several approaches starting with the cheap D-serine (mirror form of normal L-serine) were published by different groups.

[19] In the U.S., the price of cycloserine increased from $500 for 30 pills to $10,800 in 2015 after the Chao Center for Industrial Pharmacy and Contract Manufacturing changed ownership to Rodelis Therapeutics in August 2015.