openFDA text is shown for search and cross-checking; DailyMed SPL is canonical.
Warnings sections page 1 of 1 · 2 matching rows.
warnings and cautions
Inadequate restriction of tyrosine and phenylalanine intake can lead to elevations in plasma tyrosine, which at levels above 500 μmol/L can result in ocular or other complications. ( 5.1 ) Do not adjust Orfadin dosage in order to lower the plasma tyrosine concentration ( 5.1 ) Leucopenia and thrombocytopenia have been observed with treatment with Orfadin. Monitor platelet and white blood cell counts regularly during Orfadin therapy. ( 5.2 )
warnings and cautions
5 WARNINGS AND PRECAUTIONS 5.1 High Plasma Tyrosine Levels Orfadin is an inhibitor of 4-hydroxyphenyl-pyruvate dioxygenase, an enzyme in the tyrosine metabolic pathway [see Clinical Pharmacology (12) ]. Therefore, treatment with Orfadin may cause an increase in blood tyrosine in patients with HT-1, and patients should maintain concomitant reduction in dietary tyrosine and phenylalanine while on Orfadin treatment. Plasma tyrosine levels should be maintained below 500 μmol/L. Inadequate restriction of tyrosine and phenylalanine intake may increase blood tyrosine levels and may be associated with blood tyrosine levels greater than 500 μmol/L leading to the following: Ocular signs and symptoms including corneal ulcers, corneal opacities, keratitis, conjunctivitis, eye pain, and photophobia have been reported in patients treated with Orfadin [see Adverse Reactions (6) ]. Therefore, ophthalmologic examination including slit-lamp examination should be performed prior to initiating Orfadin treatment. Patients who develop photophobia, eye pain, or signs of inflammation such as redness, swelling, or burning of the eyes during treatment with Orfadin should undergo slit-lamp reexamination and immediate measurement of the plasma tyrosine concentration. Variable degrees of mental retardation and developmental delay. In patients treated with Orfadin who exhibit an abrupt change in neurologic status, a clinical laboratory assessment including plasma tyrosine levels should be performed. Painful hyperkeratotic plaques on the soles and palms. In patients with HT-1 treated with dietary restrictions and Orfadin who develop elevated plasma tyrosine levels, an assessment of dietary tyrosine intake should be performed.
Most common adverse reactions (incidence >2%) are hepatic neoplasm, liver failure, thrombocytopenia, leucopenia, visual system complaints including conjunctivitis, corneal opacity, keratitis, and photophobia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact: Accredo Health Group at 1-888-454-8860 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
adverse reactions
6 ADVERSE REACTIONS The following serious adverse reactions are described below and elsewhere in the labeling: High Plasma Tyrosine Levels [see Warnings and Precautions (5.1) ]. Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the 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 clinical practice.