ORNIDYL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ORNIDYL (ORNIDYL).
Irreversible inhibitor of ornithine decarboxylase (ODC), thereby depleting polyamines essential for cell growth and differentiation.
| Metabolism | Metabolized primarily by the liver via unknown pathways; minimal renal excretion of unchanged drug. |
| Excretion | Renal: ~80% as unchanged drug; biliary/fecal: minimal (<5%) |
| Half-life | Terminal half-life: 4–6 hours in normal renal function; prolonged in renal impairment (up to 12–24 hours) |
| Protein binding | ~70% bound to plasma proteins (albumin and globulins) |
| Volume of Distribution | ~0.5 L/kg; indicates moderate extravascular distribution |
| Bioavailability | Oral: ~50–80% (variable due to first-pass metabolism); IV: 100% |
| Onset of Action | IV: Onset within minutes; oral: 1–2 hours |
| Duration of Action | IV: 6–8 hours; oral: 8–12 hours; clinical effect persists for duration of treatment course |
400 mg/kg/day IV divided every 6 hours for 14 days; alternatively, 100 mg/kg IV every 6 hours for 14 days.
| Dosage form | INJECTABLE |
| Renal impairment | No specific GFR-based guidelines; use with caution in renal impairment due to potential accumulation; consider dose reduction if CrCl <30 mL/min. |
| Liver impairment | No specific Child-Pugh based guidelines; use with caution in hepatic impairment. |
| Pediatric use | Neonates and infants: 100 mg/kg IV every 6 hours for 14 days. Older children: 400 mg/kg/day IV divided every 6 hours for 14 days. |
| Geriatric use | No specific adjustments; use with caution due to age-related renal and hepatic function decline; monitor for adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ORNIDYL (ORNIDYL).
| Breastfeeding | No data on excretion in human milk; M/P ratio unknown. Caution advised due to potential adverse effects on nursing infant (e.g., bone marrow suppression, ototoxicity). |
| Teratogenic Risk | FDA Pregnancy Category C. No adequate studies in pregnant women. In animal studies, eflornithine (the active ingredient in ORNIDYL) was teratogenic at doses similar to human doses. First trimester: potential teratogenic effects (skeletal abnormalities, embryotoxicity). Second and third trimesters: risk of fetal harm unknown; use only if benefit outweighs risk. |
■ FDA Black Box Warning
WARNING: Thrombocytopenia and anemia have been reported; monitor platelet counts and hemoglobin levels regularly.
| Serious Effects |
["Hypersensitivity to eflornithine or any component of the formulation","Severe bone marrow suppression"]
| Precautions | ["Bone marrow suppression: monitor blood counts frequently","Seizures: may lower seizure threshold; use caution in patients with epilepsy","Ototoxicity: hearing loss reported; audiometry recommended","Hepatotoxicity: monitor liver function tests","Gastrointestinal effects: nausea, vomiting, diarrhea"] |
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| Fetal Monitoring |
| Monitor complete blood counts (CBC) weekly for thrombocytopenia and leukopenia. Monitor liver function tests (LFTs) and renal function. In pregnant patients, consider fetal ultrasound for skeletal development if first trimester exposure. Monitor for signs of ototoxicity and peripheral neuropathy. |
| Fertility Effects | Eflornithine may impair fertility in females and males based on animal studies (reversible ovulatory suppression and decreased spermatogenesis). Human data are lacking. |