Cystadane

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Cystadane

Classes

Homocystinuria Agents

Administration
Oral Administration

Regular administration of betaine is required to maintain the effects of the drug; betaine effects will cease upon discontinuation of therapy.
Shake bottle lightly before removing the cap.
Measure the appropriate number of scoops for the prescribed dose with the scoop provided. One level scoop (1.7 mL) of powder equals 1 g of betaine anhydrous.
Mix the dose with 4 to 6 ounces (120 to 180 mL) of water, juice, milk, or formula until completely dissolved. Alternatively, mix the dose with food. Ingest immediately.
Replace the cap tightly after use and protect the bottle from moisture.[57277]

Adverse Reactions
Severe

cerebral edema / Early / Incidence not known

Moderate

glossitis / Early / Incidence not known
depression / Delayed / Incidence not known
urinary incontinence / Early / Incidence not known

Mild

diarrhea / Early / 0-1.0
nausea / Early / 2.0
dyspepsia / Early / 2.0
abdominal pain / Early / Incidence not known
vomiting / Early / Incidence not known
anorexia / Delayed / Incidence not known
emotional lability / Early / Incidence not known
irritability / Delayed / Incidence not known
insomnia / Early / Incidence not known
agitation / Early / Incidence not known
drug-induced body odor / Delayed / Incidence not known
alopecia / Delayed / Incidence not known
urticaria / Rapid / Incidence not known

Common Brand Names

Cystadane

Dea Class

Rx

Description

Orally administered methyl group donor
Used for the treatment of homocystinuria; monitor plasma homocysteine concentrations
Do not confuse with betaine HCl salt form

Dosage And Indications
For the adjunct treatment of homocystinuria in order to reduce plasma homocysteine levels; including in those patients with deficiencies or defects in 1) cystathionine beta-synthase (CBS); 2) 5,10-methylenetetrahydrofolate reductase (MTHFR); and 3) cobalamin cofactor metabolism (cbl).
NOTE: Betaine is designated as an orphan drug by the FDA for this indication.
NOTE: In patients with CBS-deficiency, monitor plasma methionine concentrations.
NOTE: Response to treatment is usually evident within 1 week, and steady state is reached within roughly 1 month.
Oral dosage Adults

The usual dosage is 3 g PO twice daily (6 g/day total). Higher dosages (up to 20 g/day) have been necessary to control plasma homocysteine levels in some patients. However, dosages in all patients can be gradually increased until plasma homocysteine concentrations are undetectable or present only in small amounts. One pharmacokinetic and pharmacodynamic study of 6 children (6 to 17 years of age) indicated a potential plateau of benefit at roughly 150 mg/kg/day PO.

Children and Adolescents 3 years and older

The usual dosage is 3 g PO twice daily (6 g/day total). Higher dosages (up to 20 g/day) have been necessary to control plasma homocysteine levels in some patients. However, dosages in all patients can be gradually increased until plasma homocysteine concentrations are undetectable or present only in small amounts. One pharmacokinetic and pharmacodynamic study of 6 children (6 to 17 years of age) indicated a potential plateau of benefit at roughly 150 mg/kg/day PO.

Neonates, Infants, and Children younger than 3 years

Dosage may be started at 100 mg/kg/day PO given in divided doses twice daily. Dosage may be increased weekly by 50 mg/kg increments. Dosages in all patients can be gradually increased until plasma homocysteine concentrations are undetectable or present only in small amounts. Of note, one pharmacokinetic and pharmacodynamic study of 6 children (6 to 17 years of age) indicated a potential plateau of benefit at roughly 150 mg/kg/day PO.

Dosing Considerations
Hepatic Impairment

No data are available.

Renal Impairment

No data are available.
 

Drug Interactions

There are no drug interactions associated with Betaine Anhydrous products.

How Supplied

Betaine, Anhydrous/Cystadane Oral Pwd F/Recon: 1g

Maximum Dosage

Maximum dosage information is not available. Dosage and therapy should be guided by clinical status and the reduction of plasma homocysteine levels to undetectable or small amounts.

Mechanism Of Action

Betaine serves as a methyl donor in one of the two pathways in humans that methylate homocysteine to methionine. In therapeutic doses, betaine facilitates the remethylation of homocysteine to methionine. Administration of betaine reduces elevated plasma homocysteine levels by roughly 20—30% and improves the clinical symptoms of the disease. Response usually occurs within 1 week and steady-state response to any given dosage within 1 month.

Pharmacokinetics

Betaine is administered orally. Detailed pharmacokinetic data are not available. The plasma levels of betaine have not been measured in patients and have not been correlated with plasma homocysteine levels. However, the measurement of homocysteine levels in the presence of betaine administration indicate that betaine's onset of action is within a few days of beginning therapy and that a steady-state response to any given dose is achieved within several weeks to 1 month's time.

Pregnancy And Lactation
Pregnancy

Available data from a limited number of published case reports and postmarketing experience with betaine use in pregnancy have not identified any drug associated risks for major birth defects, miscarriage, or adverse maternal or fetal outcomes. Animal reproduction studies have not been performed with betaine.[57277] Betaine should be given to pregnant women only when clearly needed. There is a published case report of the continuation of betaine and other management therapies in a pregnant woman with homocystinuria; the woman experienced two successful pregnancies, and 2 healthy infants were delivered. However, the woman had experienced a miscarriage in a prior pregnancy, details of which were unknown.[32038] Because of the rarity of the base disease, it is unlikely that sufficient data will be available to judge whether betaine, when given in pharmacologic doses, can affect reproduction capacity or cause fetal harm. Clearly, because betaine is found naturally in the diet, the normal daily intake of betaine from dietary food sources is not thought harmful.

It is not known whether betaine is excreted in human milk (although its metabolic precursor, choline, occurs at high levels in human milk). As many drugs are excreted in human milk, caution should be exercised when betaine is administered to a woman who is breast-feeding. Because of the rarity of homocystinuria it is unlikely that sufficient data will be available to judge whether betaine, when given in pharmacologic doses, has an effect on breast-feeding. Clearly, because betaine is found naturally in the diet, the normal daily intake of betaine from dietary food sources is not thought harmful.