Information about Betaine
Betaine is a modified amino acid consisting of glycine with three methyl groups that serves as a methyl donor in several metabolic pathways and is used to treat the rare genetic causes of homocystinuria.
Liver safety of Betaine
Betaine has had only limited clinical use, but has not been linked to instances of serum enzyme elevations during therapy or to clinically apparent liver injury.
Betaine (bee' ta een) is a naturally occurring modified amino acid that is used therapeutically to treat genetic homocystinuria. Homocystinuria can be caused by several inherited defects in sulfur amino acid metabolism, the most common of which are cystathionine β-synthase deficiency (CβS) and 5,10-methylenetetrahydrofolate reductase (MTHRF) deficiency. Typically, plasma levels of homocysteine and methionine are elevated while cysteine is decreased. Children with these deficiencies develop [[mental retardation[[, ocular lens dislocations, skeletal deformities and early onset atherosclerosis. Most evidence indicates that the high levels of homocysteine are the major cause of the clinical complications.
Mechanism of action of Betaine
Therapy of homocystinuria includes a low methionine diet, pyridoxine, a cofactor for cystathionine beta-synthase, and betaine which results in a decrease in homocysteine levels and amelioration of the clinical manifestations. Betaine is believed to act by increasing methylation reactions, one of which causes homocysteine to be metabolized to methionine. Betaine is an important nutrient that can be obtained from foods (such as beets), synthesized endogenously from choline, or provided as a supplement in patients with impaired folate status or inherited deficiencies of enzymes involved in transsulfuration pathways. The liver is rich in betaine but levels may be somewhat reduced in patients with liver disease.
FDA approval information for Betaine
Betaine was approved as an orphan drug for use in homocystinuria in 1996 and is available as a powder for reconstitution in bottles of 180 grams under the brand name Cystadane.
Dosage and administration for Betaine
The typical dose of Betaine is 3 to 10 grams twice daily.
Side effects of Betaine
Side effects are dose related and can include gastrointestinal upset with diarrhea, bloating, cramps, dyspepsia, nausea and vomiting. Rare, but potentially severe side effects include excessive increases in serum methionine concentrations which may lead to life-threatening cerebral edema.
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Huntington disease agents
Urea Cycle Disorder Agents