Wednesday, July 19, 2023

DOXOrubicin (dox-oh-roo-bi-sin) Adriamycin, Caelyx, Myocet

 Indications

Alone or with other modalities in the treatment of various

solid tumors including: Breast, Ovarian, Bladder,

Bronchogenic carcinoma, Malignant lymphomas and

leukemias.

Action

Inhibits DNA and RNA synthesis by forming a complex

with DNA; action is cell-cycle S-phase–specific. Also

has immunosuppressive properties. Therapeutic

Effects: Death of rapidly replicating cells, particularly

malignant ones.

Pharmacokinetics

Absorption: Administered IV only, resulting in complete

bioavailability.

Distribution: Widely distributed; does not cross the

blood-brain barrier; extensively bound to tissues.

Metabolism and Excretion: Mostly metabolized

by the liver (primarily by CYP2D6 and CYP3A4). Converted

by liver to an active compound. Excreted predominantly

in the bile, 50% as unchanged drug. Less

than 5% eliminated unchanged in the urine.

Half-life: 16.7 hr.

TIME/ACTION PROFILE (effect on blood

counts)

ROUTE ONSET PEAK DURATION

IV 10 days 14 days 21–24 days

Contraindications/Precautions

Contraindicated in: Hypersensitivity; OB, Lactation:

Pregnancy or lactation.

Use Cautiously in: History of cardiac disease or

high cumulative doses of anthracyclines; Depressed

bone marrow reserve; Liver impairment (reduce dose if

serum bilirubin 1.2 m g/dL); Pedi, Geri: Children,

geriatric patients, mediastinal radiation, concurrent cyclophosphamide

(qrisk of cardiotoxicity); Rep: Patients

with childbearing potential.

Adverse Reactions/Side Effects

Resp: recall pneumonitis. CV: CARDIOMYOPATHY,

ECG changes. GI: diarrhea, esophagitis, nausea, stomatitis,

vomiting. GU: red urine. Derm: alopecia,

photosensitivity. Endo: sterility, prepubertal growth

failure with temporary gonadal impairment (children

only). Hemat: anemia, leukopenia, thrombocytopenia.

Local: phlebitis at IV site, tissue necrosis. Metab:

hyperuricemia. Misc: hypersensitivity reactions.

Interactions

Drug-Drug: CYP2D6 inhibitors, CYP3A4 inhibitors,

and P-glycoprotein inhibitors mayqrisk of

toxicity; avoid concurrent use. CYP2D6 inducers,

CYP3A4 inducers, and P-glycoprotein inducers

maypeffect andqrisk of therapeutic failure; avoid

concurrent use.qbone marrow depression with other

antineoplastics or radiation therapy. Pediatric patients

who have received concurrent doxorubicin and

dactinomycin have anqrisk of recall pneumonitis at

variable times following local radiation therapy. Mayq

skin reactions at previous radiation therapy sites. If

paclitaxel is administered first, clearance of doxorubicin

ispand the incidence and severity of neutropenia

and stomatitis areq(problem is diminished if doxorubicin

is administered first). Hematologic toxicity isq

and prolonged by concurrent use of cyclosporine;

risk of coma and seizures is alsoq. Incidence and severity

of neutropenia and thrombocytopenia areqby

concurrent progesterone. Phenobarbital mayq

clearance and decrease effects of doxorubicin. Doxorubicin

maypmetabolism andqeffects of phenytoin.

Streptozocin mayqthe half-life of doxorubicin (dosagepof

doxorubicin recommended). Mayqrisk of

hemorrhagic cystitis from cyclophosphamide. Mayq

risk of hepatotoxicity from mercaptopurine. Cardiac

toxicity may beqby radiation therapy or cyclophosphamide.

qrisk of cardiac toxicity with trastuzumab;

avoid concurrent use. If dexrazoxane is administered

at initiation of doxorubicin-containing regimens, may

qrisk of therapeutic failure and tumor progression.

Maypantibody response to live-virus vaccines and

qrisk of adverse reactions.

Route/Dosage

Other regimens are used.

IV (Adults): 60–75 mg/m2 daily, repeat q 21 days; or

25–30 mg/m2 daily for 2–3 days, repeat q 3–4 wk or

20 mg/m2/wk. Total cumulative dose should not exceed

550 mg/m2 without monitoring of cardiac function or

400 mg/m2 in patients with previous chest radiation or

other cardiotoxic chemotherapy.

IV (Children): 30 mg/m2/day for 3 days every 4 wk.

Hepatic Impairment

IV (Adults): Serum bilirubin 1.2–3mg/dL—50% of

usual dose; serum bilirubin 3.1–5 mg/dL—25% of

usual dose.

Availability (generic available)

Powder for injection: 10 mg/vial, 20 mg/vial, 50 mg/

vial, 150 mg/vial. Solution for injection: 2 mg/mL.

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