Therapy with Cystadane should be directed by physicians knowledgeable in the management of patients with homocystinuria.
Hypermethioninemia
Patients with homocystinuria due to cystathionine beta-synthase (CBS) deficiency may also have elevated plasma methionine concentrations. Treatment with Cystadane may further increase methionine concentrations due to the remethylation of homocysteine to methionine. Cerebral edema has been reported in patients with hypermethioninemia, including a few patients treated with Cystadane. Plasma methionine concentrations should be monitored in patients with CBS deficiency. Plasma methionine concentrations should be kept below 1,000 umol/L through dietary modification and, if necessary, a reduction of Cystadane dose.
Information for patients
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Shake bottle lightly before removing cap.
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Measure with the scoop provided.
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One level scoop (1.7 cc) is equivalent to 1 gram of betaine anhydrous powder. Measure the number of scoops your physician has prescribed.
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Mix with 4 to 6 ounces (120 to 180 mL) of water, juice, milk, or formula until completely dissolved, or mix with food, then ingest immediately.
Always replace the cap tightly after using. Protect from moisture.
Carcinogenesis, mutagenesis, impairment of fertility
Long-term carcinogenicity and fertility studies have not been conducted on betaine. No evidence of genotoxicity was demonstrated in the following tests: Metaphase Analysis of Human Lymphocytes; Bacterial Reverse Mutation Assay; and Mouse Micronucleus Test.
Pregnancy
Pregnancy Category C. Animal reproduction studies have not been conducted with betaine. It is also not known whether betaine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Cystadane (betaine anhydrous for oral solution) should be given to a pregnant woman only if clearly needed.
Nursing mothers
It is not known whether betaine is excreted in human milk (although its metabolic precursor, choline, occurs at high levels in human milk). Because many drugs are excreted in human milk, caution should be exercised when Cystadane is administered to a nursing woman.
Pediatric use
The majority of case studies of homocystinuria patients treated with betaine have been pediatric patients. The disorder, in its most severe form, can be manifested within the first months or years of life by lethargy, failure to thrive, developmental delays, seizures, or optic lens displacement. Patients have been treated successfully without adverse effects within the first months or years of life with dosages of 6 grams per day or more of betaine with resultant biochemical and clinical improvement. However, dosage titration may be preferable in pediatric patients (see DOSAGE AND ADMINISTRATION).
ADVERSE REACTIONS
Adverse reactions to betaine have been minimal. In a survey study of physicians who had treated a total of 111 homocystinuria patients with betaine, the types of adverse effects and the number of patients experiencing them were as follows:
|
Nausea |
2 |
“Caused odor” |
1 |
|
GI distress |
2 |
Questionable psychological changes |
1 |
|
Diarrhea |
1 |
“Aspirated the powder” |
1 |
|
Unspecified problem |
|
