Dosing and uses of Xuriden, Vistogard (uridine triacetate)
Adult dosage forms and strengths
oral granules
- 2g/packet (Xuriden)
- 10g/packet (Vistogard)
Hereditary Orotic Aciduria
60 mg/kg PO qDay mixed with milk; increase dose to 120 mg/kg (not to exceed 8 g) qDay for insufficient efficacy as follows:
Levels of orotic acid in urine remain above normal or increase above the usual or expected range for patient
Laboratory values (eg, red blood cell or white blood cell indices) affected by hereditary orotic aciduria show evidence of worsening
Worsening of other signs or symptoms of the disease
Total daily dose by weight category below was rounded to achieve approximate dose level (2 g = 3/4 tsp)
Total daily dose by weight category below rounded to achieve approximate dose level at the 120-mg/kg dose leveL
- 41-45 kg: 2.5-2.7 g (1 tsp)
- 46-50 kg: 2.8-3 g (1 tsp)
- 51-55 kg: 3.1-3.3 g (1.25 tsp)
- 56-60 kg: 3.4-3.6 g (1.25 tsp)
- 61-65 kg: 3.7-3.9 g (1.5 tsp; may use 2 entire 2-g packets without weighing or measuring)
- 66-70 kg: 4-4.2g (1.5 tsp; may use 2 entire 2-g packets without weighing or measuring)
- 71-75 kg: 4.3-4.5g (1.5 tsp; may use 2 entire 2-g packets without weighing or measuring)
- >75 kg: 6 g (2 tsp; may use 3 entire 2-g packets without weighing or measuring)
Total daily dose by weight category below rounded to achieve approximate dose level at the 120-mg/kg dose leveL
- 41-45 kg: 5-5.4 g (2 tsp; may use 3 entire 2-g packets without weighing or measuring)
- 46-50 kg: 5.6–6 g (2 tsp; may use 3 entire 2-g packets without weighing or measuring)
- 51-55 kg: 6.2-6.6 g (2.5 tsp)
- 56-60 kg: 6.8-7.2 g (2.5 tsp)
- 61-65 kg: 7.4-7.8 g (2.5 tsp)
- ≥66-70 kg: 8 g (2.75 tsp; may use 4 entire 2-g packets without weighing or measuring)
Fluorouracil or Capecitabine Overdose
Indication
- Pyrimidine analog indicated for emergency treatment of adults and children:
- Following a fluorouracil or capecitabine overdose regardless of the presence of symptoms, or
- Patients exhibiting early-onset, severe or life-threatening toxicity affecting the cardiac or CNS, and/or early onset, unusually severe adverse reactions (eg, GI toxicity and/or neutropenia) within 96 hr following the end of fluorouracil or capecitabine administration
- Limitations of use
- Not recommended for nonemergent treatment of adverse reactions associated with fluorouracil or capecitabine because it may diminish the efficacy of these drugs
- Safety and efficacy of uridine triacetate initiated >96 hr following the end of fluorouracil or capecitabine administration have not been established
Dose
- Adults: 10 g (1 packet) PO q6hr for 20 doses
- May take without regard to meals
Pediatric dosage forms and strengths
oral granules
- 2g/packet (Xuriden)
- 10g/packet (Vistogard)
Hereditary Orotic Aciduria
60 mg/kg PO qDay mixed with milk/infant formula; increase dose to 120 mg/kg (not to exceed 8 g) qDay for insufficient efficacy as follows:
Levels of orotic acid in urine remain above normal or increase above the usual or expected range for patient
Laboratory values (eg, red blood cell or white blood cell indices) affected by hereditary orotic aciduria show evidence of worsening
Worsening of other signs or symptoms of the disease
Total daily dose by weight category below was rounded to achieve approximate dose level (2 g = 3/4 tsp)
Total daily dose by weight category below rounded to achieve approximate dose level at the 60 mg/kg dose leveL
- ≥5 kg: 0.4 g (1/8 tsp)
- 6-10 kg: 0.4-0.6 g (1/4 tsp)
- 11-15 kg: 0.7-0.9 g (1/2 tsp)
- 16-20 kg: 1-1.2 g (1/2 tsp)
- 21-25 kg: 1.3-1.5 g (1/2 tsp)
- 26-30 kg: 1.6-1.8 g (3/4 tsp; may use 1 entire 2-g packet without weighing or measuring)
- 31-35 kg: 1.9-2.1 g (3/4 tsp; may use 1 entire 2-g packet without weighing or measuring)
- 36-40 kg: 2.2-2.4 g (1 tsp)
- 41-45 kg: 2.5-2.7 g (1 tsp)
- 46-50 kg: 2.8-3 g (1 tsp)
- 51-55 kg: 3.1-3.3 g (1.25 tsp)
- 56-60 kg: 3.4-3.6 g (1.25 tsp)
- 61-65 kg: 3.7-3.9 g (1.5 tsp)
- 66-70 kg: 4.3-4.5 g (1.5 tsp)
- >70 kg: 6 g (2 tsp; may use 3 entire 2-g packets without weighing or measuring)
Total daily dose by weight category below rounded to achieve approximate dose level at the 120 mg/kg dose leveL
- ≥5 kg: 0.8 g (1/4 tsp)
- 6-10 kg: 0.8-1.2 g (1/2 tsp)
- 11-15 kg: 1.4-1.8 g (3/4 tsp)
- 16-20 kg: 2-2.4 g (1 tsp)
- 21-25 kg: 2.6-3 g (1 tsp)
- 26-30 kg: 3.2-3.6 g (1.25 tsp)
- 31-35 kg: 3.8-4.2 g (1.5 tsp; may use 2 entire 2-g packets without weighing or measuring)
- 36-40 kg: 4.4-4.8 g (1.75 tsp)
- 41-45 kg: 5-5.4 g (2 tsp; may use 3 entire 2-g packets without weighing or measuring)
- 46-50 kg: 5.6-6 g (2 tsp; may use 3 entire 2-g packets without weighing or measuring)
- 51-55 kg: 6.2-6.6 g (2/25 tsp)
- 56-60 kg: 6.8-7/2 g (2.5 tsp)
- 61-65 kg: 7.4-7.8 g (2.5 tsp)
- ≥66 kg: 8 g (2.75 tsp; may use 4 entire 2-g packets without weighing or measuring)
Fluorouracil or Capecitabine Overdose
Indication
- Pyrimidine analog indicated for emergency treatment of adults and children:
- Following a fluorouracil or capecitabine overdose regardless of the presence of symptoms, or
- Patients exhibiting early-onset, severe or life-threatening toxicity affecting the cardiac or CNS, and/or early onset, unusually severe adverse reactions (eg, GI toxicity and/or neutropenia) within 96 hr following the end of fluorouracil or capecitabine administration
- Limitations of use
- Not recommended for nonemergent treatment of adverse reactions associated with fluorouracil or capecitabine because it may diminish the efficacy of these drugs
- Safety and efficacy of uridine triacetate initiated >96 hr following the end of fluorouracil or capecitabine administration have not been established
Dose
- 6.2 g/m² PO q6hr for 20 doses; not to exceed 10 g/dose
- May take without regard to meals
- Total daily dose by body surface area rounded to achieve approximate dose
- 0.34-0.44 m²: 2.1-.27 g (1 tsp)
- 0.45-0.55 m²: 2.8-34 g (1.25 tsp)
- 0.56-0.66 m²: 3.5-4.1 g (1.5 tsp)
- 0.67-0.77 m²: 4.2-4.8 g (1.75 tsp)
- 0.78-0.88 m²: 4.9-5.4 g (2 tsp)
- 0.89-0.99 m²: 5.5-6.1 g (2.25 tsp)
- 1-1.1 m²: 6.2-6.8 g (2.5 tsp)
- 1.11 to 1.21 m²: 6.9-7.5 g (2.75 tsp)
- 1.22-1.32 m²: 7.6-8/1 g (3 tsp)
- 1.33-1.43 m²: 8.2-8.8 g (3.25 tsp)
- ≥1.44 m²: 10 g (1 full packet)
Xuriden, Vistogard (uridine triacetate) adverse (side) effects
1-10% (Vistogard)
Vomiting (10%)
Nausea (5%)
Diarrhea (3%)
Warnings
Contraindications
None reported by the manufacturer
Cautions
None reported by the manufacturer
Pregnancy and lactation
Pregnancy: There are no available data in pregnant women to determine a drug-associated risk; when administered orally to pregnant rats during period of organogenesis, uridine triacetate at doses similar to maximum recommended human dose (MRHD) of 120 mg/kg/day was not teratogenic and did not produce adverse effects on embryo-fetal development
Lactation: There are no data on presence of uridine triacetate in human milk, effect on the breastfed infant, or effect on milk production; development and health benefits of breastfeeding should be considered along with the mother’s clinical need for the therapy and any potential adverse effects on breastfed infant from the therapy or from the underlying maternal condition
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Xuriden, Vistogard (uridine triacetate)
Mechanism of action
Uridine triacetate is an acetylated prodrug of uridine
Following oral administration, uridine triacetate is deacetylated by nonspecific esterases present throughout the body, yielding uridine in the circulation
Hereditary orotic aciduria
- Patients with hereditary orotic aciduria cannot synthesize adequate quantities of uridine because of a genetic defect in uridine nucleotide synthesis
Fluorouracil or capecitabine toxicity
- Uridine can be converted in UMP (a pyrimidine nucleotide) that competitively inhibits cell damage and cell death caused by fluorouracil
- Capecitabine is converted to fluorouracil by thymidine phosphorylase
- Fluorouracil is a cytotoxic antimetabolite that interferes with nucleic acid metabolism in normal and cancer cells; cells anabolize fluorouracil to the cytotoxic intermediates 5-fluoro-2’-deoxyuridine-5’- monophosphate (FdUMP) and 5-fluorouridine triphosphate (FUTP)
- FdUMP inhibits thymidylate synthase, blocking thymidine synthesis, which is required for DNA replication and repair Uridine is not found in DNA
- The second source of fluorouracil cytotoxicity is the incorporation of its metabolite, FUTP, into RNA, which is proportional to systemic fluorouracil exposure
- Excess circulating uridine derived from uridine triacetate is converted into uridine triphosphate (UTP), which competes with FUTP for incorporation into RNA
Absorption
Peak plasma time: 2-3 hr
Distribution
Distributed in mammalian cells and via nucleoside transporters
Metabolism
Metabolized by esterase enzymatic activity
Elimination
Half-life: 2-2.5 hr
Excretion: Kidneys and most tissues
Administration
Oral Preparation
Measure dose using either a scale accurate to at least 0.1 g, or a graduated teaspoon, accurate to fraction of dose to be administered
Once measured dose is removed from packet, discard unused portion of granules; do not use any granules left in the open packet
Oral Administration (Xuriden)
Administer drug mixed in milk or infant formula
Pour 5 mL of milk or infant formula into 30-mL medicine cup
Insert tip of oral syringe into medicine cup and draw up 5 mL of milk/infant formula into syringe
Hold syringe with tip pointing upward; pull down on plunger until plunger reaches 10 mL; this will add air to the syringe
Place cap over tip of syringe; invert syringe so syringe tip is pointing down, and remove plunger
Pour measured amount of granules into syringe barrel and reinsert syringe plunger; do not push up on plunger
Gently swirl syringe to mix granules with liquid
Turn syringe so syringe tip is pointing up; remove syringe cap and push up on plunger until plunger reaches 5 mL mark; this will remove air from the syringe
Place tip of syringe in patient’s mouth between cheek and gum at back of mouth; gently push plunger all the way down
Refill syringe with another 5 mL of milk/infant formula
Gently swirl syringe to rinse any remaining granules from syringe barreL
Place tip of syringe in patient’s mouth between cheek and gum at back of mouth; gently push plunger all the way down
Follow with bottle of milk or infant formula, if desired
Oral Administration (Vistogard)
Mix each dose with 3-4 oz of soft foods (eg, applesauce, pudding, yogurt) and ingest within 30 minutes of mixing
Do not chew the granules
Drink at least 4 oz of water after consuming dose
If a patient vomits within 2 hr of taking a dose, initiate another complete dose as soon as possible after the vomiting episode, and then administer the next dose at the regularly scheduled time
If a patient misses a dose at the scheduled time, administer that dose as soon as possible, and then administer the next dose at the regularly scheduled time
Administer via a NG-tube or G-tube when necessary (eg, severe mucositis, coma)
