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Busilvex (UK), Busulfex, Myleran
Pharmacologic class: Alkylating agent
Therapeutic class: Antineoplastic
Pregnancy risk category D
FDA Box Warning
• Drug causes profound myelosuppression at recommended dosage. Give under supervision of physician experienced in allogeneic hematopoietic stem cell transplantation, cancer chemotherapy, and management of severe pancytopenia, in facility with adequate diagnostic and treatment resources.
Unclear. Thought to interfere with bacterial cell-wall synthesis by cross-linking strands of DNA and disrupting RNA transcription, which causes cell to rupture and die. Exhibits minimal immunosuppressant activity.
Injection: 6 mg/ml in 10-ml ampules
Tablets: 2 mg
⊘Indications and dosages
➣ Chronic myelogenous leukemia
Adults: 4 to 8 mg P.O. daily until white blood cell (WBC) count decreases to 15,000/mm3; then discontinue drug until WBC count rises to 50,000/mm3, and then resume as needed.
Children: 0.06 to 0.12 mg/kg/day P.O. or 1.8 to 4.6 mg/m2/day P.O. Adjust dosage to maintain WBC count at approximately 20,000/mm3. Drug should be withheld when WBC count decreases to approximately 15,000/mm3.
➣ Allogenic hematopoietic stem cell transplantation
Adults: 0.8 mg/kg I.V. q 6 hours for 4 days. Starting 6 hours after 16th dose of busulfan injection, give cyclophosphamide 60 mg/kg/day I.V. over 1 hour for 2 days.
• Adjunctive therapy in ovarian cancer
• Bone marrow transplantation
• Hypersensitivity to drug
• Patients not definitively diagnosed with chronic myelogenous leukemia
• Pregnancy or breastfeeding
Use cautiously in:
• active infections, decreased bone marrow reserve, chronic debilitating disease, depressed neutrophil and platelet counts, seizure disorders, obesity
• patients receiving concurrent myelosuppressive or radiation therapy
• females of childbearing age.
• Give oral doses on empty stomach.
• When administering I.V., withdraw dose from ampule using 5-micron filter needle. Remove filter needle and use new needle to add busulfan to diluent.
• Dilute for injection using dextrose 5% in water or normal saline solution.
• Infuse I.V. dose over 2 hours, using an infusion pump.
• Flush I.V. catheter before and after each infusion with 5 ml D5W or normal saline solution.
☞ Be aware that drug is highly toxic and has a narrow therapeutic index.
• Maintain vigorous hydration to reduce risk of renal toxicity.
• Handle patient gently to avoid bruising.
CNS: anxiety, confusion, depression, dizziness, headache, insomnia, weakness, encephalopathy, seizures, cerebral hemorrhage, coma
CV: chest pain, hypotension, hypertension, tachycardia, ECG changes, heart block, left-sided heart failure, thrombosis, pericardial effusion, ventricular extrasystole, atrial fibrillation, arrhythmias, cardiac tamponade, cardiomegaly
EENT: cataracts, ear disorders, epistaxis, pharyngitis
GI: nausea, vomiting, diarrhea, constipation, abdominal pain, dyspepsia, abdominal enlargement, pancreatitis, hematemesis, dry mouth, stomatitis, anorexia
GU: dysuria, hematuria, sterility, gyne-comastia, oliguria
Hematologic: febrile neutropenia, thrombotic microangiopathy, profound myelosuppression
Hepatic: hepatitis, hepatomegaly
Metabolic: hypokalemia, hypomagnesemia, hypophosphatemia, hyperuricemia, hyperglycemia
Musculoskeletal: arthralgia, myalgia, back pain
Respiratory: hyperventilation, dyspnea, pulmonary fibrosis
Skin: pruritus, rash, acne, alopecia, erythema nodosum, exfoliative dermatitis, hyperpigmentation
Other: allergic reactions, chills, fever, injection site infection or inflammation; severe bacterial, viral, fungal infections; sepsis; tumor lysis syndrome
Drug-drug.Anticoagulants, aspirin, nonsteroidal anti-inflammatory drugs: increased risk of bleeding
Live-virus vaccines: decreased antibody response to vaccine, increased risk of adverse reactions
Myelosuppressants: additive bone marrow depression
Nephrotoxic and ototoxic drugs (such as aminoglycosides, loop diuretics): additive nephrotoxicity and ototoxicity
Thioguanine: increased risk of hepatotoxicity
Drug-diagnostic tests.Alkaline phosphatase, aspartate aminotransferase, bilirubin, nitrogenous compounds (urea): increased levels
Hemoglobin, WBCs: decreased values
• Monitor patient closely for adequate hydration.
• Check for signs and symptoms of local or systemic infections.
• Assess for bleeding and excessive bruising.
• Evaluate oral hygiene regularly.
• Monitor CBC and WBC and platelet counts daily if patient is receiving I.V. busulfan.
• Monitor renal and hepatic function.
☞ Know that diffuse pulmonary fibrosis ("busulfan lung") is a rare but potentially life-threatening complication, with symptom onset as late as 10 years after therapy.
• Inform patient that drug doesn't cure leukemia but may induce remission.
• Advise patient to drink plenty of fluids to avoid dehydration.
☞ Instruct patient to immediately report inability to eat or drink. Prescriber may add another drug to improve appetite.
• Inform patient that he's at increased risk for infection. Advise him to avoid contact with people with known infections and to avoid public transportation, if possible.
• Tell patient he's at increased risk for bleeding and bruising.
• Advise patient to avoid activities that can cause injury and to use soft toothbrush and electric razor to avoid gum and skin injury.
• Inform patient that he'll undergo frequent blood testing to monitor drug effects.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.
Pharmacologic: alkylating agents
Time/action profile (effects on blood counts)
|PO||1–2 wk||weeks||up to 1 mo†|
Adverse Reactions/Side EffectsIncidence and severity of adverse reactions and side effects are increased with IV use
Central nervous system
- seizures (life-threatening)
- cerebral hemorrhage/coma (life-threatening)
- anxiety (most frequent)
- confusion (most frequent)
- depression (most frequent)
- dizziness (most frequent)
- headache (most frequent)
- mental status changes
- weakness (most frequent)
Ear, Eye, Nose, Throat
- cataracts IV:
- epistaxis (most frequent)
- pharyngitis (most frequent)
- ear disorders
- hepatic veno-oclusive disease (↑ allogenic transplantation)
- pulmonary fibrosis (life-threatening) IV:
- alveolar hemorrhage
- pleural effusion
- cardiac tamponade (with high-dose cyclophosphamide) (life-threatening) IV:
- chest pain (most frequent)
- hypotension (most frequent)
- tachycardia (most frequent)
- thrombosis (most frequent)
- atrial fibrillation
- ECG changes
- heart block
- heart failure
- pericardial effusion
- ventricular extrasystoles
- drug-induced hepatitis
- vomiting IV:
- abdominal enlargement (most frequent)
- anorexia (most frequent)
- constipation (most frequent)
- diarrhea (most frequent)
- dry mouth (most frequent)
- hematemesis (most frequent)
- nausea (most frequent)
- rectal discomfort (most frequent)
- vomiting (most frequent)
- abdominal pain
- oliguria (most frequent)
- itching (most frequent)
- rashes (most frequent)
- erythema nodosum
- exfoliative dermatitis
- sterility (most frequent)
Fluid and Electrolyte
- hypokalemia (most frequent)
- hypomagnesemia (most frequent)
- hypophosphatemia (most frequent)
- bone marrow depression (life-threatening)
- inflammation/pain at injection site (most frequent)
- PO and IV:
- hyperuricemia IV:
- hyperglycemia (most frequent)
- arthralgia (most frequent)
- myalgia (most frequent)
- back pain
- allergic reactions (most frequent)
- chills (most frequent)
- fever (most frequent)
- infection (most frequent)
Drug-Drug interactionConcurrent or previous (within 72 hr) use of acetaminophen may ↓ elimination and ↑ toxicity.Concurrent use with high-dose cyclophosphamide in patients with thalassemia may result in cardiac tamponade.Concurrent use with itraconazole or phenytoin ↓ blood level effectiveness.Long-term continuous therapy with thioguanine may ↑ risk of hepatic toxicity.↑ bone marrow suppression with other antineoplastics or radiation therapy.May ↓ the antibody response to and ↑risk of adverse reactions from live-virus vaccines.
Route/DosageMany other regimens are used. See current protocols for up-to-date dosage
- high alert: Monitor for bone marrow depression. Assess for bleeding (bleeding gums, bruising, petechiae, guaiac stools, urine, emesis) and avoid IM injections and taking rectal temperatures. Apply pressure to venipuncture sites for at least 10 min. Assess for signs of infection (fever, chills, sore throat, cough, hoarseness, lower back or side pain, difficult or painful urination) during neutropenia. Anemia may occur. Monitor for increased fatigue, dyspnea, and orthostatic hypotension. Notify health care professional if these symptoms occur.
- Monitor intake and output ratios and daily weights. Report significant changes in totals.
- Monitor for symptoms of gout (increased uric acid, joint pain, lower back or side pain, swelling of feet or lower legs). Encourage patient to drink at least 2 L of fluid each day. Allopurinol may be given to decrease uric acid levels. Alkalinization of urine may be ordered to increase excretion of uric acid.
- Assess for pulmonary fibrosis (fever, cough, shortness of breath) periodically during and after therapy. Discontinue therapy at the first sign of pulmonary fibrosis. Usually occurs 8 mo–10 yr (average 4 yr) after initiation of therapy.
- Intravenous: Premedicate patient with phenytoin before IV administration to minimize the risk of seizures.
- Administer antiemetics before IV administration and on a fixed schedule throughout IV administration.
- Lab Test Considerations: Monitor CBC with differential and platelet count before and weekly during therapy. The nadir of leukopenia occurs within 10–15 days and the nadir of WBC at 11–30 days. Recovery usually occurs within 12–20 wk. Notify health care professional if WBC is <15,000/mm3 or if a precipitous drop occurs. Institute thrombocytopenia precautions if platelet count is <150,000/mm3. Bone marrow depression may be severe and progressive, with recovery taking 1 mo–2 yr after discontinuation of therapy.
- Monitor serum ALT, bilirubin, alkaline phosphatase, and uric acid before and periodically during therapy. May cause ↑ uric acid levels.
- May cause false-positive cytology results of breast, bladder, cervix, and lung tissues.
Potential Nursing DiagnosesDisturbed body image (Side Effects)
Risk for injury (Side Effects)
Risk for infection (Side Effects)
- high alert: Fatalities have occurred with chemotherapeutic agents. Before administering, clarify all ambiguous orders; double check single, daily, and course-of-therapy dose limits; have second practitioner independently double check original order, calculations, and infusion pump settings.
- high alert: Do not confuse Myleran with Alkeran or Leukeran.
- Oral: Administer at the same time each day. Administer on an empty stomach to decrease nausea and vomiting.
- pH: 3.4–3.9.
- Intravenous: Prepare solution in a biologic cabinet. Wear gloves, gown, and mask while handling IV medication. Discard IV equipment in specially designated containers.
- Intermittent Infusion: Diluent: Dilute with 10 times the volume of busulfan using 0.9% NaCl or D5W.Concentration: ≥0.5 mg/mL. When drawing busulfan from vial, use needle with 5-micron nylon filter provided, remove calculated volume from vial, remove needle and filter, replace needle and inject busulfan into diluent. Do not use polycarbonate syringes with busulfan. Only use filters provided with busulfan. Always add busulfan to diluent, not diluent to busulfan. Solution diluted with 0.9% NaCl or D5W is stable for 8 hr at room temperature and solution diluted with 0.9% NaCl is stable for 12 hr if refrigerated. Administration must be completed during this time. Solution is clear and colorless; do not administer solutions that are discolored or contain a precipitate.
- Rate: Administer via central venous catheter over 2 hr every 6 hr for 4 days for a total of 16 doses. Use infusion pump to administer entire dose over 2 hr.
- Y-Site Compatibility: acyclovir, amphotericin B lipid complex, amphotericin B liposome, anidulafungin, argatroban, bivalirudin, bleomycin, caspofungin, daptomycin, dexmedetomidine, diltiazem, docetaxel, ertapenem, fenoldopam, granisetron, hetastarch, hydromorphone, levofloxacin, linezolid, lorazepam, meperidine, metronidazole, milrinone, nesiritide, octreotide, ondansetron, paclitaxel, palonosetron, pancuronium, piperacillin/tazobactam, potassium acetate, quinupristin/dalfopristin, rituximab, sodium acetate, tacrolimus, tigecycline, tirofiban, trastuzumab, vasopressin, zoledronic acid
- Y-Site Incompatibility: idarubicin, thiotepa, vecuronium, voriconazole
- Instruct patient to take medication as directed, at the same time each day, even if nausea and vomiting are a problem. Consult health care professional if vomiting occurs shortly after dose is taken. If a dose is missed, do not take at all; do not double doses.
- Advise patient to notify health care professional if fever; sore throat; signs of infection; lower back or side pain; difficult or painful urination; sores in the mouth or on the lips; chills; dyspnea; persistent cough; bleeding gums; bruising; petechiae; or blood in urine, stool, or emesis occurs. Instruct patient to use soft toothbrush and electric razor. Caution patient not to drink alcoholic beverages or take products containing aspirin or NSAIDs.
- Caution patient to avoid crowds and persons with known infections. Health care professional should be informed immediately if symptoms of infection occur.
- Discuss with patient the possibility of hair loss. Explore methods of coping.
- Instruct patient not to receive any vaccinations without advice of health care professional.
- Advise patient to notify health care professional if unusual bleeding; bruising; or flank, stomach, or joint pain occurs. Advise patients on long-term therapy to notify health care professional immediately if cough, shortness of breath, and fever occur or if darkening of skin, diarrhea, dizziness, fatigue, anorexia, confusion, or nausea and vomiting become pronounced.
- Inform patient of increased risk of a second malignancy with busulfan.
- Review with patient the need for contraception during therapy. Women need to use contraception even if amenorrhea occurs.
- Decrease in leukocyte count to within normal limits.
- Decreased night sweats.
- Increase in appetite.
- Increased sense of well-being. Therapy is resumed when leukocyte count reaches 50,000/mm3.
BusulfexAn injectable busulfan combined with cyclophosphamide to condition/ablate the bone marrow before allogeneic hematopoietic progenitor/stem cell transplantation in patients with CML.
Profound myelosuppression, hepatotoxicity (raised liver enzymes), venoocclusive disease, neurotoxicity (seizures).