Cystadane

/ Medison

Cystadane treatment should be supervised by a physician experienced in the treatment of patients with homocystinuria.
Adult: The recommended total daily dose in adult is 6 g per day administered orally in divided doses of 3 g two times per day.
Paediatric population: The recommended total daily dose in paediatric patients over 10 years of age is the same as adult. However, dose titration may be preferable in paediatric patients.
In paediatric patients less than 10 years of age, the usual effective dose regimen is 100 mg/kg/day given in 2 doses daily; increasing the frequency above twice daily and/or the dose above 150 mg/kg/day does not improve the homocysteine-lowering effect.
Hepatic or renal impairment: Experience with betaine anhydrous therapy in patients with renal insufficiency or nonalcoholic hepatic steatosis has demonstrated no need to adapt the dose regimen of Cystadane.
Method of administration: The bottle should be lightly shaken before opening.Measuring spoons are provided which dispense 1 g of betaine anhydrous. It is recommended that a heaped measuring spoon is removed from the container and a flat surface e.g. base of a knife is drawn across the top of the measure. This will give 1 g of betaine anhydrous.
The powder should be mixed with water, juice, milk, formula or food until completely dissolved and ingested immediately after mixing.
Therapeutic monitoring: The aim of treatment is to keep plasma levels of total homocysteine below 15 μM or as low as possible. The steady-state response usually occurs within a month.

Treatment of homocystinuria.
Cystadane should be used as supplement to other therapies such as vitamin B6 (pyridoxine), vitamin B12 (cobalamin), folate and a specific diet.

Hypersensitivity to the active substance.

Uncommon cases of severe cerebral oedema and hypermethioninemia were reported within 2 weeks to 6 months of starting betaine anhydrous therapy in patients with CBS deficiency. Complete recovery was seen after treatment discontinuation:
– Plasma methionine level should be monitored, at start of treatment and periodically thereafter. The plasma methionine concentrations should be kept below 1000 μM.
– If any symptoms of cerebral oedema like morning headaches with vomiting and/or visual changes appear, plasma methionine level and compliance to the diet should be checked and treatment with Cystadane interrupted.
– If symptoms of cerebral oedema recur after re-introduction of treatment then betaine anhydrous therapy should be discontinued indefinitely.
To minimise the risk of potential drug interactions, it is advisable to leave 30 minutes between the intake of betaine anhydrous and amino acids mixtures and/or medicinal products containing vigabatrin and GABA analogues.
See prescribing information for full details.

In general, adverse reactions seen with betaine anhydrous therapy appeared to be not serious and are mainly related to the gastrointestinal system. Gastrointestinal disorders like diarrhoea, glossitis, nausea, stomach discomfort, vomiting and dental disorders may occur uncommonly.
The most commonly reported adverse reaction during treatment is blood methionine increased. Complete recovery was seen after treatment discontinuation.
See prescribing information for full details.

No interaction studies have been performed.
Based on in vitro data, betaine anhydrous might interact with amino acids mixtures and medicinal products containing vigabatrin and GABA analogues.

Pregnancy: Data on a limited number of exposed pregnancies indicate no adverse event of betaine anhydrous on pregnancy or on the health of the foetus/newborn child. To date, no other relevant epidemiologic data are available. Animal reproduction studies have not been conducted. During pregnancy, administering betaine anhydrous in addition to pyridoxine, folate, anticoagulant and diet under close monitoring of plasma homocysteine would be compatible with good maternal and foetal outcomes. However, Cystadane should not be used during pregnancy unless clearly necessary.
Breastfeeding: It is not known whether betaine anhydrous is excreted in human milk (although its metabolic precursor, choline, occurs at high levels in human milk). Because of lack of data, caution should be exercised when prescribing Cystadane to breast-feeding women.

No case of overdose has been reported.