Sapropterin dihydrochloride, the active pharmaceutical ingredient in Kuvan Tablets, is a synthetic preparation of the dihydrochloride salt of naturally occurring tetrahydrobiopterin (BH4). Kuvan is indicated to reduce blood phenylalanine (Phe) levels in patients with hyperphenylalaninemia (HPA) due to tetrahydrobiopterin- (BH4-) responsive Phenylketonuria (PKU). Kuvan is to be used in conjunction with a Phe-restricted diet. Kuvan has received orphan drug designation from both the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMEA). Kuvan is a synthetic form of BH4, the cofactor for the enzyme phenylalanine hydroxylase (PAH). PAH hydroxylates Phe through an oxidative reaction to form tyrosine. In patients with PKU, PAH activity is absent or deficient. Treatment with BH4 can activate residual PAH enzyme, improve the normal oxidative metabolism of Phe, and decrease Phe levels in some patients.

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.

Mesna is an organosulfur compound used as an adjuvant in cancer chemotherapy involving cyclophosphamide and ifosfamide. No clinical drug interaction studies have been conducted with mesna. Mesna concentrates in the bladder where acrolein accumulates after administration of chemotherapy and through a Michael addition, forms a conjugate with acrolein and other urotoxic metabolites. This conjugation reaction inactivates the urotoxic compounds to harmless metabolites. The most common adverse reactions (> 10%) when MESNEX is given with ifosfamide are nausea, vomiting, constipation, leukopenia, fatigue, fever, anorexia, thrombocytopenia, anemia, granulocytopenia, diarrhea, asthenia, abdominal pain, headache, alopecia, and somnolence.

Hemin (trade name Panhematin) is a protoporphyrin IX containing a ferric iron ion (heme B) with a chloride ligand, which is is indicated for the amelioration of recurrent attacks of acute intermittent porphyria temporally related to the menstrual cycle in susceptible women. Manifestations such as pain, hypertension, tachycardia, abnormal mental status and mild to progressive neurologic signs may be controlled in selected patients with this disorder. the therapy for the acute porphyrias is not curative. Heme acts to limit the hepatic and/or marrow synthesis of porphyrin. This action is likely due to the inhibition of δ-aminolevulinic acid synthetase, the enzyme which limits the rate of the porphyrin/heme biosynthetic pathway. The exact mechanism by which hematin produces symptomatic improvement in patients with acute episodes of the hepatic porphyrias has not been elucidated.

Bromocriptine is an ergot derivative with potent dopamine receptor agonist activity, which activates post-synaptic dopamine receptors. Bromocriptine is indicated for the treatment of dysfunctions associated with hyperprolactinemia. Bromocriptine therapy is indicated in the treatment of acromegaly and in the treatment of the signs and symptoms of idiopathic or postencephalitic Parkinson’s disease. It is approved as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Some commonly reported adverse reactions include nausea, fatigue, dizziness, vomiting and headache. Bromocriptine may interact with dopamine antagonists, butyrophenones and certain other agents.