Cystadane

The usual dosage used in adult and pediatric patients is 6 grams per day administered orally in divided doses of 3 grams two times per day. Dosages of up to 20 grams per day have been necessary to control homocysteine levels in some patients. In pediatric patients less than 3 years of age, dosage may be started at 100 mg/kg/day and then increased weekly by 50 mg/kg increments. In one study by Matthewsi et al., pharmacokinetic and pharmacodynamic simulation indicated minimal benefit from exceeding a twice-daily dosing schedule and a 150 mg/kg/day dosage for betaine. Dosage in all patients can be gradually increased until plasma total homocysteine is undetectable or present only in small amounts. Plasma methionine concentrations should be monitored in patients with CBS-deficiency. See PRECAUTIONS: Hypermethioninemia.

The prescribed amount of Cystadane (betaine anhydrous for oral solution) should be measured with the measuring scoop provided (one level 1.7 cc scoop is equal to 1 gram of betaine anhydrous powder) and then dissolved in 4 to 6 ounces (120 to 180 mL) of water, juice, milk, or formula, or mixed with food for immediate ingestion.

2.1 Dosage

The usual dosage in adult and pediatric patients is 6 grams per day administered orally in divided doses of 3 grams twice daily.  In pediatric patients less than 3 years of age, dosage may be started at 100 mg/kg/day divided in twice daily doses, and then increased weekly by 50 mg/kg increments. 
Therapy with Cystadane should be directed by physicians knowledgeable in the management of patients with homocystinuria.  Patient response to Cystadane can be monitored by homocysteine plasma levels.  Dosage in all patients can be gradually increased until plasma total homocysteine is undetectable or present only in small amounts. Response (by homocysteine plasma levels) usually occurs within several days and steady state within a month.  Plasma methionine concentrations should be monitored in patients with CBS deficiency [See Warnings and Precautions (5.1)].

Dosages of up to 20 grams per day have been necessary to control homocysteine levels in some patients.  However, one pharmacokinetic and pharmacodynamic in vitro simulation study indicated minimal benefit from exceeding a twice-daily dosing schedule and a 150 mg/kg/day dosage for Cystadane.

2.2 Administration

The prescribed amount of Cystadane should be measured with the measuring scoop provided (one level 1.7 mL scoop is equal to 1 gram of betaine anhydrous powder) and then dissolved in 4 to 6 ounces (120 to 180 mL) of water, juice, milk, or formula, or mixed with food for immediate ingestion.