Usual Adult Dose for Cystinuria

The dose should be based on that amount required to reduce urinary cystine concentration to below its solubility limit (generally less than 250 mg/L).

• Initial dose: 800 mg orally daily in divided doses 3 times a day
• Maintenance dose: 1000 mg orally daily or less in divided doses 3 times a day

Comments:

• Urinary cystine should be measured at 1 month after beginning therapy and every 3 months thereafter; adjust the dose depending on the urinary cystine value.
• Before beginning therapy with this drug conservative treatment should be attempted first.

Use: In combination with high fluid intake, alkali, and diet modification, for the prevention of cystine stone formation in patients with severe homozygous cystinuria, who are not responsive to these measures alone

Usual Pediatric Dose for Cystinuria

The dose should be based on that amount required to reduce urinary cystine concentration to below its solubility limit (generally less than 250 mg/L).

9 to 18 years: 15 mg/kg/day orally in divided doses 3 times a day

Comments:

• Urinary cystine should be measured at 1 month after beginning therapy and every 3 months thereafter. Adjust the dose depending on the urinary cystine value.
• Before beginning therapy with this drug conservative treatment should be attempted first.

Use: In combination with high fluid intake, alkali, and diet modification, for the prevention of cystine stone formation in pediatric patients 20 kg and greater with severe homozygous cystinuria, who are not responsive to these measures alone

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Dose Adjustments

In patients who have shown toxicity to d-penicillamine, this drug may be started at a lower dose.

The dose of this drug should be adjusted to reduce urinary cystine concentrations below its solubility limit (generally less than 250 mg/L).

Precautions

CONTRAINDICATIONS:

• Hypersensitivity to the active component or any of the ingredients

Safety and efficacy have not been established in patients younger than 9 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

• This drug should be given at least 1 hour before or 2 hours after meals.
• For patients who can swallow semi-solid food, the tablet can be crushed and mixed with applesauce:
• Crush the tablet in a clean pill crusher or mortar and pestle.
• Always crush one tablet at a time.
• Measure approximately 1 tablespoon of applesauce and transfer it into a container with the crushed tablet.
• Mix the crushed tablet in the applesauce until the powder is well dispersed.
• Administer the entire mixture to the patient's mouth immediately (however, if this is not possible, the mixture can be stored in a refrigerator for up to 2 hours after adding the crushed tablet to the applesauce).
• To assure that any leftover applesauce mixture from the container is recovered, add tap water to the same container, mix, and have the patient drink the water.

Storage requirements:

• Store at 25C (77F); excursions permitted to 15C to 30C (59F to 86F).

Monitoring:

• Peripheral blood counts
• Direct platelet count
• Hemoglobin
• Serum albumin
• Liver function tests
• Twenty-four-hour urinary protein and routine urinalysis at 3- to 6-month intervals during therapy.
• To assess effect on stone disease, urinary cystine analysis should be monitored frequently during the first 6 months when the optimum dose schedule is being determined, and at 6-month intervals thereafter.
• Abdominal roentogenogram (KUB) is advised on a yearly basis to monitor the size and appearance/disappearance of stone(s).