Betaine Drug Information

Betaine Anhydrous for Oral Solution is indicated for the treatment of homocystinuria to decrease elevated homocysteine blood concentrations in pediatric and adult patients. Included within the category of homocystinuria are Cystathionine beta-synthase (CBS) deficiency 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency Cobalamin cofactor metabolism (cbl) defect Betaine Anhydrous for Oral Solution is a methylating agent indicated in pediatric and adult patients for the treatment of homocystinuria to decrease elevated homocysteine blood concentrations. Included within the category of homocystinuria are: Cystathionine beta-synthase (CBS) deficiency 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency Cobalamin cofactor metabolism (cbl) defect

Dosage Therapy with Betaine Anhydrous for Oral Solution should be directed by

physicians knowledgeable in the management of patients with homocystinuria. Adults and Pediatric Patients 3 Years of Age and Older The recommended dosage is 6 grams per day, administered orally in divided doses of 3 grams twice daily. Pediatric Patients Less than 3 Years of Age The recommended starting dosage is 100 mg/kg/day divided in twice daily doses, and then increased weekly by 50 mg/kg increments.

Monitoring Monitor patient response to Betaine Anhydrous for Oral Solution by homocysteine plasma concentration. Increase the dosage in all patients gradually until the plasma total homocysteine concentration is undetectable or present only in small amounts. An initial response in homocysteine plasma concentrations usually occurs within several days and steady state plasma concentrations occur within a month.

Monitor plasma methionine concentrations in patients with CBS deficiency. Maximum Dosage Dosages of up to 20 grams/day have been necessary to control homocysteine concentrations 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 Betaine Anhydrous for Oral Solution.

Preparation and

Administration Instructions Shake bottle lightly before removing cap. Measure the number of scoops for the patient's dose with the scoop provided. One level scoop (1.9cc) is equivalent to 1 gram of betaine anhydrous powder.

Mix powder with 4 to 6 ounces (120 to 180 mL) of water, juice, milk, or formula until completely dissolved, or mix with food, then ingest mixture immediately. Always replace the cap tightly after using and protect the bottle from moisture.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The assessment of clinical adverse reactions is based on a survey study of 41 physicians, who treated a total of 111 homocystinuria patients with Betaine Anhydrous for Oral Solution. Adverse reactions were retrospectively recalled and were not collected systematically in this open-label, uncontrolled, physician survey.

Thus, this list may not encompass all types of potential adverse reactions, reliably estimate their frequency, or establish a causal relationship to drug exposure. The following adverse reactions were reported (Table 1): Table 1: Number of Patients with Adverse Reactions to Betaine Anhydrous for Oral Solution by Physician Survey Adverse Reactions Number of Patients Nausea 2 Gastrointestinal distress 2 Diarrhea 1 "Bad Taste" 1 "Caused Odor" 1 Questionable psychological changes 1 "Aspirated the powder" 1

Post-marketing Experience

The following adverse reactions have been identified during post approval use of Betaine Anhydrous for Oral Solution. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Severe cerebral edema and hypermethioninemia have been reported within 2 weeks to 6 months of starting Betaine Anhydrous for Oral Solution therapy, with complete recovery after discontinuation of Betaine Anhydrous for Oral Solution.

All patients who developed cerebral edema had homocystinuria due to CBS deficiency and had severe elevation in plasma methionine concentrations (range 1,000 to 3,000 microM). As cerebral edema has also been reported in patients with hypermethioninemia, secondary hypermethioninemia due to betaine therapy has been postulated as a possible mechanism of action . Other adverse reactions include: anorexia, agitation, depression, irritability, personality disorder, sleep disturbed, dental disorders, diarrhea, glossitis, nausea, stomach discomfort, vomiting, hair loss, hives, skin odor abnormalities, and urinary incontinence.

Pregnancy Risk Summary Available data from a limited number of published case reports and post marketing experience with Betaine Anhydrous for Oral Solution 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 conducted with betaine. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown.

All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Pediatric Use The safety and effectiveness of Betaine Anhydrous for Oral Solution have been established in pediatric patients. The majority of case studies of homocystinuria patients treated with Betaine Anhydrous for Oral Solution have been pediatric patients, including patients ranging in age from 24 days to 17 years. Children younger than 3 years of age may benefit from dose titration.

There is no information on Betaine Anhydrous for Oral Solution overdose in humans. In an acute toxicology study in rats, death occurred frequently at doses equal to or greater than 10 g/kg.