Warnings for Olpruva
Included as part of the PRECAUTIONS section.
Precautions for Olpruva
Neurotoxicity Of Phenylacetate
Increased exposure to phenylacetate, the major metabolite of OLPRUVA, may be associated with neurotoxicity in patients with UCDs. In a study of adult cancer patients receiving intravenous phenylacetate, 250-300 mg/kg/day for 14 days, repeated at 4-week intervals, signs and symptoms of neurotoxicity, which were reversible upon discontinuation, were seen at plasma concentrations ≥ 3.5 mmol/L, and included somnolence, fatigue, and light headedness [see ADVERSE REACTIONS]. OLPRUVA is not approved for intravenous use or for treatment of patients with cancer.
If symptoms of vomiting, nausea, headache, somnolence, or confusion are present in the absence of high ammonia levels or other intercurrent illnesses, consider reducing the dose of OLPRUVA [see DOSAGE AND ADMINISTRATION].
Phenylacetate caused neurotoxicity when given subcutaneously in rat pups [see Use In Specific Populations].
Hypokalemia
Renal excretion of phenylacetylglutamine may induce urinary loss of potassium. Monitor serum potassium during therapy and initiate appropriate treatment when necessary.
Conditions Associated With Edema
OLPRUVA contains 124 mg (5.4 mmol) of sodium per gram of sodium phenylbutyrate (12.4% w/w) and the Mix-Aid contains 5 mg of sodium per packet, corresponding to 2.5 g (108 mmol) of sodium in the maximum daily dose of 20 g of OLPRUVA. In order to decide if administration of OLPRUVA is appropriate in patients with diseases that involve edema, such as heart failure, cirrhosis, or nephrosis, calculate the total amount of sodium patients will be exposed to based on their BSAs [see DOSAGE AND ADMINISTRATION]. If a patient develops new-onset edema or worsening edema while on treatment, discontinue administration of OLPRUVA and initiate appropriate therapy.
Patient Counseling Information
Advise the patient to read the FDA-approved patient labeling (PATIENT INFORMATION and Instructions for Use).
Neurotoxicity
Advise the patient or caregiver that neurotoxicity may occur during OLPRUVA treatment. Inform the patient or caregiver of the signs and symptoms of this risk and to contact the healthcare provider immediately if signs and symptoms occur [see WARNINGS AND PRECAUTIONS].
Preparation And Administration
Inform the patient or caregiver that the OLPRUVA packet(s) must be mixed with the prepared Mix-Aid suspension and to drink the entire suspension within 5 minutes after stirring to minimize dissolution of coating. After 30 minutes, the suspension should be discarded [see DOSAGE AND ADMINISTRATION].
Inform the patient or caregiver that if a dose is missed, take the missed dose as soon as possible on the same day [see DOSAGE AND ADMINISTRATION].
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment Of Fertility
Carcinogenicity, mutagenicity, and fertility studies of sodium phenylbutyrate have not been conducted.
Use In Specific Populations
Pregnancy
Risk Summary
Available data with sodium phenylbutyrate use in pregnant women are insufficient to identify a drug associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. Animal reproduction studies have not been conducted with sodium phenylbutyrate. Based on published animal data, phenylacetate may be neurotoxic to the developing brain (see Data).
There are serious risks to the mother and fetus associated with untreated urea cycle disorders during pregnancy which can result in serious morbidity and mortality to the mother and fetus (see Clinical Considerations).
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.
Clinical Considerations
Disease-Associated Maternal And/Or Embryo/Fetal Risk
Pregnancy is a time of increased metabolic demand which increases the risk for hyperammonemic episodes when metabolic demands are not met. Hyperammonemic episodes in pregnancy are associated with impaired cognition in the mother and an increased risk of maternal and fetal death.
Data
Animal Data
In rats, intrauterine exposure to phenylacetate produced lesions in the neonatal brain in layer 5 of the cortical pyramidal cells; dendritic spines were longer and thinner than normal and reduced in number.
Lactation
Risk Summary
There are no data on the presence of sodium phenylbutyrate and its metabolite in either human or animal milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for OLPRUVA and any potential adverse effects on the breastfed infant from OLPRUVA or from the underlying maternal condition.
Pediatric Use
The safety and effectiveness of OLPRUVA have been established as adjunctive therapy to the standard of care, which includes dietary management, in the chronic management of pediatric patients weighing 20 kg or greater and with a body surface area 1.2 m² or greater, with urea cycle disorders (UCDs) involving deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS).
OLPRUVA is not indicated for the treatment of acute hyperammonemia which can be a life-threatening medical emergency that requires rapid acting interventions to reduce plasma ammonia levels.
The sodium content of OLPRUVA has the potential to cause new-onset edema or worsening edema from salt and water retention, particularly in patients with underlying predisposing conditions [see WARNINGS AND PRECAUTIONS].
OLPRUVA is not approved in pediatric patients weighing less than 20 kg or in pediatric patients weighing 20 kg or greater with a BSA of less than 1.2 m².
Neurotoxicity has been observed in juvenile animals with phenylacetate exposure [see WARNINGS AND PRECAUTIONS].
Juvenile Animal Toxicity Data
When given subcutaneously to neonatal rats, 190-474 mg/kg phenylacetate caused decreased proliferation and increased loss of neurons, and it reduced CNS myelin. Cerebral synapse maturation was retarded, and the number of functioning nerve terminals in the cerebrum was reduced, which resulted in impaired brain growth.
Geriatric Use
Clinical studies of OLPRUVA did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function and of concomitant disease or other drug therapy.
Renal Impairment
No studies with OLPRUVA were conducted in subjects with renal impairment. Monitor plasma ammonia levels when starting patients with impaired renal function on OLPRUVA [see CLINICAL PHARMACOLOGY].
Hepatic Impairment
No studies with OLPRUVA were conducted in subjects with hepatic impairment. Start at the lower end of the recommended dosing range and maintain patients with hepatic impairment on the lowest dose necessary to control plasma ammonia levels [see CLINICAL PHARMACOLOGY, DOSAGE AND ADMINISTRATION].