FLUDARA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FLUDARA (FLUDARA).
Fludarabine is a purine nucleotide analog that inhibits DNA synthesis by interfering with ribonucleotide reductase and DNA polymerase, leading to cell death in dividing lymphocytes.
| Metabolism | Fludarabine is dephosphorylated in serum to 9-β-D-arabinofuranosyl-2-fluoroadenine (F-ara-A), which is then phosphorylated intracellularly to active triphosphate (F-ara-ATP). Further metabolism involves deamination by adenosine deaminase, but the primary route is renal excretion of unchanged drug and metabolites. |
| Excretion | Renal: 60% excreted unchanged in urine; biliary/fecal: <5% as metabolites. |
| Half-life | Fludarabine phosphate: 0.7-1 h (rapid dephosphorylation). Active metabolite 2-fluoro-ara-A: terminal t1/2 20-30 h (up to 40 h in renal impairment). |
| Protein binding | Fludarabine: 19-29% (primarily albumin); 2-fluoro-ara-A: minimal binding. |
| Volume of Distribution | Vd: 2.4 L/kg (fludarabine); 0.5-0.9 L/kg (2-fluoro-ara-A, approximating total body water). |
| Bioavailability | Oral: 55-75% under fasting conditions; food reduces Cmax but not AUC. |
| Onset of Action | IV: Onset 2-3 days for reduction in lymphocyte count; maximal effect after 1-2 cycles. |
| Duration of Action | Duration of immunosuppression: 6-12 months after therapy; myelosuppression may persist ≥4 weeks. |
| Action Class | Antimetabolites |
| Brand Substitutes | Fludaphos 50mg Injection, Fludarither 50 Injection, Fludacel 50mg Injection, Naprobin 50mg Injection, Fludocyte 50mg Injection, Lymfuda 10mg Tablet, Fludabine 10mg Tablet |
25 mg/m^2 intravenously over 30 minutes daily for 5 consecutive days every 28 days.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl 30-70 mL/min: reduce dose by 20%. CrCl <30 mL/min: contraindicated. |
| Liver impairment | No specific recommendations for hepatic impairment; use with caution in severe hepatic impairment (Child-Pugh C). |
| Pediatric use | Not established for pediatric patients; safety and efficacy not determined. |
| Geriatric use | No specific adjustment; monitor renal function and hematologic parameters closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FLUDARA (FLUDARA).
| Breastfeeding | No data exist on fludarabine excretion into human breast milk. Given its mechanism of action (DNA synthesis inhibitor) and potential for severe adverse effects (e.g., myelosuppression, carcinogenesis) in a nursing infant, breastfeeding is contraindicated during therapy and for at least 1 week after the last dose. M/P ratio is unknown. |
| Teratogenic Risk | Fludarabine is contraindicated in pregnancy. It is a nucleoside analog with known teratogenic and embryotoxic effects. First trimester exposure is associated with major congenital malformations, particularly neural tube defects, craniofacial anomalies, and limb defects. Second and third trimester exposure can cause fetal growth restriction, myelosuppression, and increased risk of fetal death. Both animal studies and human case reports confirm significant fetal harm. |
■ FDA Black Box Warning
WARNING: FLUDARA MAY CAUSE SEVERE BONE MARROW SUPPRESSION (ANEMIA, THROMBOCYTOPENIA, NEUTROPENIA) AND MAY INDUCE AUTOIMMUNE HEMOLYTIC ANEMIA. PATIENTS SHOULD BE MONITORED CLOSELY FOR HEMATOLOGIC TOXICITY. NEUROTOXICITY (INCLUDING BLINDNESS, COMA, AND DEATH) HAS BEEN REPORTED, PARTICULARLY AT HIGH DOSES (>40 mg/m2/day).
| Serious Effects |
["Hypersensitivity to fludarabine or any component of the formulation","Severe renal impairment (CrCl <30 mL/min) unless benefit outweighs risk","Pregnancy (can cause fetal harm)","Lactation (discontinue nursing or drug)"]
| Precautions | ["Severe bone marrow suppression, particularly thrombocytopenia, anemia, and neutropenia","Autoimmune hemolytic anemia, which can be fatal","Neurotoxicity, especially at high doses; monitor for altered mental status, visual disturbances, seizures","Tumor lysis syndrome, especially in patients with high tumor burden","Immunosuppression and increased risk of opportunistic infections","Pulmonary toxicity including interstitial pneumonitis","Hepatotoxicity and increased liver enzymes","Use with caution in renal impairment; dose adjustment required (CrCl <30 mL/min)"] |
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| Fetal Monitoring | If inadvertent exposure during pregnancy occurs, serial fetal ultrasounds for structural anomalies, growth parameters, and amniotic fluid volume are recommended. Maternal complete blood counts with differential and platelet count should be monitored weekly due to risk of myelosuppression. Assess for signs of infection or bleeding. Fetal heart rate monitoring may be considered after 24 weeks gestation. |
| Fertility Effects | Fludarabine can cause irreversible gonadal suppression in both sexes. In males, it may lead to azoospermia or oligospermia; in females, ovarian failure and premature menopause have been reported. Fertility preservation options (e.g., sperm or oocyte cryopreservation) should be discussed prior to initiation. Long-term data suggest a dose-dependent effect on reproductive function. |