Ramelteon was approved by the United States (U.S.) in July 2005, and the Japanese Ministry of Health, Labour and Welfare in April 2010. It is currently available in the USA and Japan as ROZEREM and is indicated for the treatment of insomnia characterized by difficulty with sleep onset. In October 7, 2011, Takeda has decided to discontinue the development of ramelteon in Europe for the treatment of insomnia in order to best optimize Takeda’s resources for its research and development activities. Ramelteon is a melatonin receptor agonist with both high affinity for melatonin MT1 and MT2 receptors and selectivity over the MT3 receptor. Ramelteon demonstrates full agonist activity in vitro in cells expressing human MT1 or MT2 receptors, and high selectivity for human MT1 and MT2 receptors compared to the MT3 receptor. The activity of ramelteon at the MT1 and MT2 receptors is believed to contribute to its sleep-promoting properties since these receptors are acted upon by endogenous melatonin and are thought to be involved in the maintenance of the circadian rhythm underlying normal sleep-wake cycles. Ramelteon has no appreciable affinity for the GABA receptor complex or for receptors that bind neuropeptides, cytokines, serotonin, dopamine, noradrenaline, acetylcholine, and opiates.

Arranon is a nucleoside metabolic inhibitor indicated for the treatment of patients with T-cell acute lymphoblastic leukemia and T-cell lymphoblastic lymphoma. It is a purine nucleoside analog converted to its corresponding arabinosylguanine nucleotide triphosphate (araGTP), resulting in inhibition of DNA synthesis and cytotoxicity. Administration of nelarabine in combination with adenosine deaminase inhibitors, such 195 as pentostatin, is not recommended. The most common (≥20%) adverse reactions were: anemia, thrombocytopenia, neutropenia, nausea, diarrhea, vomiting, constipation, fatigue, pyrexia, cough, and dyspnea

BARACLUDE® is the tradename for entecavir, a guanosine nucleoside analogue with selective activity against hepatitis B virus (HBV). It inhibits all three steps in the viral replication process. By competing with the natural substrate deoxyguanosine triphosphate, entecavir functionally inhibits all three activities of the HBV polymerase (reverse transcriptase, rt): (1) base priming, (2) reverse transcription of the negative strand from the pregenomic messenger RNA, and (3) synthesis of the positive strand of HBV DNA. Upon activation by kinases, the drug can be incorporated into the DNA which has the ultimate effect of inhibiting the HBV polymerase activity. Entecavir is used for the treatment of chronic hepatitis B virus infection in adults with evidence of active viral replication and either evidence of persistent elevations in serum aminotransferases (ALT or AST) or histologically active disease.

Clofarabine is a anti-cancer drug which was approved by FDA for the treatment of pediatric patients with relapsed or refractory acute lymphoblastic leukemia. After crossing the cell membrane the drug is rapidly metabolized by deoxycytidine kinase to diphosphate and triphosphate metabolites and these metabolites reversibly inhibit hRNR by binding to alpha subunit. Also the triphosphate is incorporated to DNA where it acts as a chain terminator.

Glutamine is a non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes. It is synthesized from glutamic acid and ammonia. It is the principal carrier of nitrogen in the body and is an important energy source for many cells. Supplemental L-glutamine's possible immunomodulatory role may be accounted for in a number of ways. L-glutamine appears to play a major role in protecting the integrity of the gastrointestinal tract and, in particular, the large intestine. During catabolic states, the integrity of the intestinal mucosa may be compromised with consequent increased intestinal permeability and translocation of Gram-negative bacteria from the large intestine into the body. The demand for L-glutamine by the intestine, as well as by cells such as lymphocytes, appears to be much greater than that supplied by skeletal muscle, the major storage tissue for L-glutamine. L-glutamine is the preferred respiratory fuel for enterocytes, colonocytes and lymphocytes. Therefore, supplying supplemental L-glutamine under these conditions may do a number of things. For one, it may reverse the catabolic state by sparing skeletal muscle L-glutamine. It also may inhibit translocation of Gram-negative bacteria from the large intestine. L-glutamine helps maintain secretory IgA, which functions primarily by preventing the attachment of bacteria to mucosal cells. L-glutamine appears to be required to support the proliferation of mitogen-stimulated lymphocytes, as well as the production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma). It is also required for the maintenance of lymphokine-activated killer cells (LAK). L-glutamine can enhance phagocytosis by neutrophils and monocytes. It can lead to an increased synthesis of glutathione in the intestine, which may also play a role in maintaining the integrity of the intestinal mucosa by ameliorating oxidative stress. The exact mechanism of the possible immunomodulatory action of supplemental L-glutamine, however, remains unclear. It is conceivable that the major effect of L-glutamine occurs at the level of the intestine. Perhaps enteral L-glutamine acts directly on intestine-associated lymphoid tissue and stimulates overall immune function by that mechanism, without passing beyond the splanchnic bed. Glutamine is used for nutritional supplementation, also for treating dietary shortage or imbalance.

Darifenacin is a selective muscarinic receptor M3 antagonist which was approved by FDA for the treatment of overactive bladder.

Acamprosate was the third medication, after disulfiram and naltrexone, to receive U.S. Food and Drug Administration (FDA) approval for postwithdrawal maintenance of alcohol abstinence. The French pharmaceutical company Laboratoires Meram began clinical development and testing of acamprosate in 1982. From 1982 to 1988, acamprosate was tested for safety and for efficacy as a treatment for alcohol dependence. Based on these studies, in 1989 Laboratoires Meram was granted marketing authorization for acamprosate in France under the trade name Aotal®. Since then, acamprosate has been extensively used and studied throughout Europe and, subsequently, in the United States. Although acamprosate has been used in Europe for more than 20 years, it was not approved by FDA until July 2004. Acamprosate became available for use in the United States in January 2005, under the trade name Campral® Delayed-Release Tablets (Merck Santé, a subsidiary of Merck KGaA, Darmstadt, Germany). Campral is currently marketed in the United States by Forest Pharmaceuticals. The mechanism of action of acamprosate in maintenance of alcohol abstinence is not completely understood. Chronic alcohol exposure is hypothesized to alter the normal balance between neuronal excitation and inhibition. in vitro and in vivo studies in animals have provided evidence to suggest acamprosate may interact with glutamate and GABA neurotransmitter systems centrally, and has led to the hypothesis that acamprosate restores this balance. It seems to inhibit NMDA receptors while activating GABA receptors.

Tinidazole is a synthetic antiprotozoal agent, formally known as 1-[2-(ethylsulfonyl)ethyl]-2-methyl-5-nitroimidazole and a second-generation 2-methyl-5-nitroimidazole. Tinidazole is a prodrug and antiprotozoal agent. The nitro group of tinidazole is reduced in Trichomonas by a ferredoxin-mediated electron transport system. The free nitro radical generated as a result of this reduction is believed to be responsible for the antiprotozoal activity. It is suggested that the toxic free radicals covalently bind to DNA, causing DNA damage and leading to cell death. The mechanism by which tinidazole exhibits activity against Giardia and Entamoeba species is not known. Tindamax oral tablets are indicated for the treatment of trichomoniasis caused by T. vaginalis in both female and male patients assuming the organism has been identified by appropriate diagnostic procedures. Because trichomoniasis is a sexually transmitted disease with potentially serious sequelae, partners of infected patients should be treated simultaneously in order to prevent re-infection. Tindamax oral tablets are also indicated for the treatment of giardiasis caused by G. duodenalis (also termed G. lamblia) in both adults and pediatric patients older than three years of age. Another indication for Tindamax oral tablets is the treatment of intestinal amebiasis and amebic liver abscess caused by E. histolytica in both adults and pediatric patients older than three years of age. It is not indicated in the treatment of asymptomatic cyst passage. The most common side effects reported with tinidazole are upset stomach, bitter taste and itchiness. Other side effects include headache, physical fatigue, and dizziness. Anecdotally, people who have taken both metronidazole and tinidazole report toxicity is much the same except the side effects don't last as long with the latter. Drinking alcohol while taking tinidazole causes an unpleasant disulfiram-like reaction which includes nausea, vomiting, headache, increased blood pressure, flushing, and shortness of breath.

Azacitidine (Vidaza; Pharmion), an inhibitor of DNA methylation, was approved by the US FDA for the treatment of myelodysplastic syndromes in May 2004. It is the first drug to be approved by the FDA for treating this rare family of bone-marrow disorders, and has been given orphan-drug status. It is also a pioneering example of an agent that targets 'epigenetic' gene silencing, a mechanism that is exploited by cancer cells to inhibit the expression of genes that counteract the malignant phenotype. VIDAZA is used for the treatment of patients with the following FAB myelodysplastic syndrome (MDS) subtypes: Refractory anemia (RA) or refractory anemia with ringed sideroblasts (RARS), refractory anemia with excess blasts (RAEB), refractory anemia with excess blasts in transformation (RAEB-T), and chronic myelomonocytic leukemia (CMMoL). Azacitidine is a pyrimidine nucleoside analog of cytidine. It is believed to exert its antineoplastic effects by causing hypomethylation of DNA and direct cytotoxicity on abnormal hematopoietic cells in the bone marrow. The concentration of azacitidine required for maximum inhibition of DNA methylation in vitro does not cause major suppression of DNA synthesis. Hypomethylation may restore normal function to genes that are critical for differentiation and proliferation. As azacitidine is a ribonucleoside, it incorporates into RNA to a larger extent than into DNA. The incorporation into RNA leads to the dissemble of polyribosomes, defective methylation and acceptor function of transfer RNA, and inhibition of the production of protein. Its incorporation into DNA leads to a covalent binding with DNA methyltransferases, which prevents DNA synthesis and subsequent cytotoxicity. The cytotoxic effects of azacitidine cause the death of rapidly dividing cells, including cancer cells that are no longer responsive to normal growth control mechanisms. Non-proliferating cells are relatively insensitive to azacitidine.