Cystadane

Before taking Cystadane, tell your doctor about all of your medical conditions. Especially tell your doctor if you:

• are allergic to Cystadane or to any of its ingredients
• are pregnant or breastfeeding

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Take Cystadane exactly as prescribed.

Cystadane comes in comes in powder form to be mixed into water, juice, milk or food. It is taken usually taken 2 times a day.

The prescribed amount of Cystadane should be measured with the measuring scoop provided and then dissolved in 4 to 6 ounces of water, juice, milk, or formula, or mixed with food for immediate ingestion.

If you miss a dose, take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose and take your next dose at the regular time. Do not take two doses of Cystadane at the same time.

Betaine is a byproduct of sugar beet processing.

Betaine works by preventing the build-up of an amino acid called homocysteine. This amino acid can harm blood vessels and contribute to heart disease, stroke, or circulation problems.

Betaine is used to reduce homocysteine levels in people with a genetic condition called homocystinuria, in which the amino acid builds up in the body. Betaine is not a cure for homocysteinuria.

Betaine may also be used for purposes not listed in this medication guide.

Betaine is used to treat a lack of or defect in certain enzymes that causes too much homocysteine in the blood and urine. This medicine removes the extra homocysteine from the body.

This medicine is available only with your doctor's prescription.

• It is used to treat homocystinuria.

• Tell all of your health care providers that you take Cystadane. This includes your doctors, nurses, pharmacists, and dentists.
• Have blood work checked as you have been told by the doctor. Talk with the doctor.
• Follow the diet plan that your doctor told you about.
• Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using this medicine while you are pregnant.
• Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

• If your symptoms or health problems do not get better or if they become worse, call your doctor.
• Do not share your drugs with others and do not take anyone else's drugs.
• Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
• Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
• Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this medicine, please talk with your doctor, nurse, pharmacist, or other health care provider.
• If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take Cystadane or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to Cystadane. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Review Date: October 4, 2017

Adverse Reactions in Clinical Studies

The most serious adverse reaction reported with Cystadane treatment is the development of hypermethioninemia and cerebral edema in patients with CBS Deficiency [see Warnings and Precautions (5.1)].

The assessment of clinical adverse reactions is based on a survey study of 41 physicians, who treated a total of 111 homocystinuria patients with Cystadane. 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):

Postmarketing Experience

The following adverse reactions have been identified during post approval use of Cystadane. 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.

In postmarketing experience with Cystadane, severe cerebral edema and hypermethioninemia have been reported within 2 weeks to 6 months of starting betaine therapy, with complete recovery after discontinuation of Cystadane. All patients who developed cerebral edema had homocystinuria due to CBS deficiency and had severe elevation in plasma methionine levels (range 1,000 to 3,000 µM). 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.

The following adverse reactions have been reported in patients during postmarketing use of Cystadane: 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

Pregnancy Category C: Animal reproduction studies have not been conducted with Cystadane. It is also not known whether Cystadane can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity.  Cystadane should be given to a pregnant woman only if clearly needed.

Nursing Mothers

It is not known whether Cystadane is excreted in human milk. Use only if clearly needed.

Pediatric Use

The majority of case studies of homocystinuria patients treated with Cystadane have been pediatric patients, including patients ranging in age from 24 days to 17 years [see Clinical Studies (14)]. Children younger than 3 years of age may benefit from dose titration [see Dosage and Administration (2)].

Cystadane was studied in a double-blind, placebo-controlled, crossover study in 6 patients with CBS deficiency, ages 7 to 32 years at enrollment. Cystadane was administered at a dosage of 3 grams twice daily, for 12 months. Plasma homocystine levels were significantly reduced (p<0.01) compared to placebo. Plasma methionine levels were variable and not significantly different compared to placebo.

No adverse events were reported in any patient.

Cystadane has also been evaluated in observational studies without concurrent controls in patients with homocystinuria due to CBS deficiency, MTHFR deficiency, or cbl defect.A review of 16 case studies and the randomized controlled trial previously described was also conducted, and the data available for each study were summarized; however, no formal statistical analyses were performed. The studies included a total of 78 male and female patients with homocystinuria who were treated with Cystadane. This included 48 patients with CBS deficiency, 13 with MTHFR deficiency, and 11 with cbl defect, ranging in age from 24 days to 53 years. The majority of patients (n=48) received 6 gm/day, 3 patients received less than 6 gm/day, 12 patients received doses from 6 to 15 gm/day, and 5 patients received doses over 15 gm/day. Most patients were treated for more than 3 months (n=57) and 30 patients were treated for 1 year or longer (range 1 month to 11 years). Homocystine is formed nonenzymatically from two molecules of homocysteine, and both have been used to evaluate the effect of Cystadane in patients with homocystinuria. Plasma homocystine or homocysteine levels were reported numerically for 62 patients, and 61 of these patients showed decreases with Cystadane treatment. Homocystine decreased by 83-88% regardless of pre-treatment level, and homocysteine decreased by 71-83%, regardless of the pre-treatment level. Clinical improvement, such as improvement in seizures, or behavioral and cognitive functioning, was reported by the treating physicians in about three-fourths of patients. Many of these patients were also taking other therapies such as vitamin B6 (pyridoxine), vitamin B12 (cobalamin), and folate with variable biochemical responses. In most cases, adding Cystadane resulted in a further reduction of either homocystine or homocysteine.

NDC 52276-400-01

Cystadane®
betaine anhydrous for oral solution

1 gram of betaine anhydrous powder per scoopful

180 grams