Cystadane (betaine)

Betaine is a methyl group donor that functions in the normal metabolic cycle of methionine and reduces homocystinuria in patients with inborn errors of methionine metabolism.

Betaine, a methyl group donor that functions in the normal metabolic cycle of methionine, occurs naturally in the body as a metabolite of choline and is present in foods such as beets, spinach, cereals, and seafood. However, natural dietary sources provide betaine in amounts insufficient to be therapeutic in patients with homocystinuria.

In patients with inborn errors of methionine metabolism and resultant homocystinuria, oral administration of betaine at recommended pharmacologic dosages results in reduction of elevated plasma concentrations of homocysteine through the action of betaine functioning as a methyl group donor in the remethylation of homocysteine to methionine. Remethylation of homocysteine to methionine is catalyzed by betaine-homocysteine S-methyltransferase and does not require 5-methyltetrahydrofolate or methylcobalamin cofactors. Because this reaction does not depend on these cofactors, betaine is effective in all 3 primary forms of homocystinuria (i.e., cystathionine beta-synthase (CBS) deficiency, 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency, and cobalamin cofactor metabolism (cbl) defect).

Betaine also can increase low plasma methionine and S-adenosylmethionine (SAM) concentrations in patients with MTHFR deficiency or cbl defect. Elevations in plasma homocysteine concentrations in conditions other than homocystinuria also have been reported.

Betaine is commercially available as an anhydrous powder, and potency of the drug is expressed on the anhydrous basis.

SumMon(R) (see Users Guide). For additional information on this drug until a more detailed monograph is developed and published, the manufacturer's labeling should be consulted. It is essential that the labeling be consulted for detailed information on the usual cautions, precautions, and contraindications.

USES: This medication is used to treat high levels of a certain important body chemical (homocysteine) due to an inherited disorder (homocystinuria). Decreasing high homocysteine levels may help prevent serious blood clots, abnormal bone formation, brittle bones (osteoporosis), and eye problems (such as dislocated eye lens, nearsightedness). This medication works by decreasing blood levels of homocysteine.

It does not correct the inherited disorder that causes the disease.

Generic name: betaine
Pronunciation: (BEE-ta-een)
Drug class: Betaine
Therapeutic class: Metabolic Modifiers

The following indications are listed for Cystadane:

• Homocystinuria

Also known as: Cystathionine Synthase Deficiency.