DOXORUBICIN HYDROCHLORIDE- doxorubicin hydrochloride injection
1. Severe local tissue necrosis will occur if there is extravasation during administration (see DOSAGE AND ADMINISTRATION). Doxorubicin must not be given by the intramuscular or subcutaneous route.
2. Myocardial toxicity manifested in its most severe form by potentially fatal congestive heart failure (CHF) may occur either during therapy or months to years after termination of therapy. The probability of developing impaired myocardial function based on a combined index of signs, symptoms and decline in left ventricular ejection fraction (LVEF) is estimated to be 1% to 2% at a total cumulative dose of 300 mg/m2 of doxorubicin, 3% to 5% at a dose of 400 mg/m2 , 5% to 8% at 450 mg/m2 and 6% to 20% at 500 mg/m2. The risk of developing CHF increases rapidly with increasing total cumulative doses of doxorubicin in excess of 400 mg/m2. Risk factors (active or dormant cardiovascular disease, prior or concomitant radiotherapy to the mediastinal/pericardial area, previous therapy with other anthracyclines or anthracenediones, concomitant use of other cardiotoxic drugs) may increase the risk of cardiac toxicity. Cardiac toxicity with doxorubicin may occur at lower cumulative doses whether or not cardiac risk factors are present. Pediatric patients are at increased risk for developing delayed cardiotoxicity.
3. Secondary acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) have been reported in patients treated with anthracyclines, including doxorubicin (see ADVERSE REACTIONS). The occurrence of refractory secondary AML or MDS is more common when anthracyclines are given in combination with DNA-damaging anti-neoplastic agents or radiotherapy, when patients have been heavily pretreated with cytotoxic drugs, or when doses of anthracyclines have been escalated. The rate of developing secondary AML or MDS has been estimated in an analysis of 8563 patients with early breast cancer treated in 6 studies conducted by the National Surgical Adjuvant Breast and Bowel Project (NSABP), including NSABP B-15. Patients in these studies received standard doses of doxorubicin and standard or escalated doses of cyclophosphamide (AC) adjuvant chemotherapy and were followed for 61,810 patient years. Among 4483 such patients who received conventional doses of AC, 11 cases of AML or MDS were identified, for an incidence of 0.32 cases per 1000 patient years (95% CI, 0.16 to 0.57) and a cumulative incidence at 5 years of 0.21% (95% CI, 0.11% to 0.41%). In another analysis of 1474 patients with breast cancer who received adjuvant treatment with doxorubicin-containing regimens in clinical trials conducted at University of Texas M.D. Anderson Cancer Center, the incidence was estimated at 1.5% at 10 years. In both experiences, patients who received regimens with higher cyclophosphamide dosages, who received radiotherapy, or who were aged 50 or older had an increased risk of secondary AML or MDS. Pediatric patients are also at risk of developing secondary AML.
4. Dosage should be reduced in patients with impaired hepatic function.
5. Severe myelosuppression may occur.
6. Doxorubicin should be administered only under the supervision of a physician who is experienced in the use of cancer chemotherapeutic agents.
Doxorubicin is a cytotoxic anthracycline antibiotic isolated from cultures of Streptomyces peucetius var. caesius. Doxorubicin consists of a naphthacenequinone nucleus linked through a glycosidic bond at ring atom 7 to an amino sugar, daunosamine. Chemically, doxorubicin hydrochloride, USP is: 5,12-Naphthacenedione, 10-[(3-amino-2,3,6-trideoxy-α-L-lyx o-hexopyranosyl)oxy]-7,8,9,10-tetrahydro-6,8,11-trihydroxy-8-(hydroxylacetyl)-1-methoxy-, hydrochloride (8S-cis)-. The structural formula is as follows:
Doxorubicin binds to nucleic acids, presumably by specific intercalation of the planar anthracycline nucleus with the DNA double helix. The anthracycline ring is lipophilic, but the saturated end of the ring system contains abundant hydroxyl groups adjacent to the amino sugar, producing a hydrophilic center. The molecule is amphoteric, containing acidic functions in the ring phenolic groups and a basic function in the sugar amino group. It binds to cell membranes as well as plasma proteins.
It is supplied in the hydrochloride form as a sterile parenteral, isotonic solution with sodium chloride for intravenous use only.
DOXOrubicin Hydrochloride Injection, USP
Each 2 mg/mL, 5 mL (10 mg) vial contains 10 mg Doxorubicin Hydrochloride, USP; Sodium Chloride 0.9% (to adjust tonicity) and Water for Injection, q.s.; Hydrochloric Acid q.s. to adjust pH between 2.5 and 4.5.
Each 2 mg/mL, 10 mL (20 mg) vial contains 20 mg Doxorubicin Hydrochloride, USP; Sodium Chloride 0.9% (to adjust tonicity) and Water for Injection, q.s.; Hydrochloric Acid q.s. to adjust pH between 2.5 and 4.5.
Each 2 mg/mL, 25 mL (50 mg) vial contains 50 mg Doxorubicin Hydrochloride, USP; Sodium Chloride 0.9% (to adjust tonicity) and Water for Injection, q.s.; Hydrochloric Acid q.s. to adjust pH between 2.5 and 4.5.
Each 2 mg/mL, 100 mL (200 mg) multiple dose vial contains 200 mg Doxorubicin Hydrochloride, USP; Sodium Chloride 0.9% (to adjust tonicity) and Water for Injection, q.s.; Hydrochloric Acid q.s. to adjust pH between 2.5 and 4.5.
The cytotoxic effect of doxorubicin on malignant cells and its toxic effects on various organs are thought to be related to nucleotide base intercalation and cell membrane lipid binding activities of doxorubicin. Intercalation inhibits nucleotide replication and action of DNA and RNA polymerases. The interaction of doxorubicin with topoisomerase II to form DNA-cleavable complexes appears to be an important mechanism of doxorubicin cytocidal activity.
Doxorubicin cellular membrane binding may affect a variety of cellular functions. Enzymatic electron reduction of doxorubicin by a variety of oxidases, reductases and dehydrogenases generates highly reactive species including the hydroxyl free radical OH•. Free radical formation has been implicated in doxorubicin cardiotoxicity by means of Cu (II) and Fe (III) reduction at the cellular level.
Cells treated with doxorubicin have been shown to manifest the characteristic morphologic changes associated with apoptosis or programmed cell death. Doxorubicin- induced apoptosis may be an integral component of the cellular mechanism of action relating to therapeutic effects, toxicities, or both.
Animal studies have shown activity in a spectrum of experimental tumors, immunosuppression, carcinogenic properties in rodents, and induction of a variety of toxic effects, including delayed and progressive cardiac toxicity, myelosuppression in all species and atrophy to testes in rats and dogs.
Pharmacokinetic studies, determined in patients with various types of tumors undergoingeither single or multi-agent therapy have shown that doxorubicin follows a multiphasicdisposition after intravenous injection. In four patients, doxorubicin has demonstrateddose-independent pharmacokinetics in the dose range of 30 to 70 mg/m2.
Distribution. The initial distribution half-life of approximately 5 minutes suggests rapid tissue uptake of doxorubicin, while its slow elimination from tissues is reflected by a terminal half-life of 20 to 48 hours. Steady-state distribution volume ranges from 809 to 1214 L/m2 and is indicative of extensive drug uptake into tissues. Binding of doxorubicin and its major metabolite, doxorubicinol, to plasma proteins is about 74% to 76% and is independent of plasma concentration of doxorubicin up to 1.1 mcg/mL.
Doxorubicin was excreted in the milk of one lactating patient, with peak milk concentration at 24 hours after treatment being approximately 4.4-fold greater than the corresponding plasma concentration. Doxorubicin was detectable in the milk up to 72 hours after therapy with 70 mg/m2 of doxorubicin given as a 15-minute intravenous infusion and 100 mg/m2 of cisplatin as a 26-hour intravenous infusion. The peak concentration of doxorubicinol in milk at 24 hours was 0.11 mcg/mL and AUC up to 24 hours was 9 mcg•h/mL while the AUC for doxorubicin was 5.4 mcg•h/mL.
Doxorubicin does not cross the blood brain barrier.
Metabolism. Enzymatic reduction at the 7 position and cleavage of the daunosamine sugar yields aglycones which are accompanied by free radical formation, the local production of which may contribute to the cardiotoxic activity of doxorubicin. Disposition of doxorubicinol (DOX-OL) in patients is formation rate limited, with the terminal half-life of DOX-OL being similar to doxorubicin. The relative exposure of DOX-OL, i.e., the ratio between the AUC of DOX-OL and the AUC of doxorubicin, compared to doxorubicin ranges between 0.4 and 0.6.
Excretion. Plasma clearance is in the range of 324 to 809 mL/min/m2 and is predominately by metabolism and biliary excretion. Approximately 40% of the dose appears in the bile in 5 days, while only 5% to 12% of the drug and its metabolites appear in the urine during the same time period. In urine, <3% of the dose was recovered as DOX-OL over 7 days.
Systemic clearance of doxorubicin is significantly reduced in obese women with ideal body weight greater than 130%. There was a significant reduction in clearance without any change in volume of distribution in obese patients when compared with normal patients with less than 115% ideal body weight.
Pharmacokinetics in Special Populations
Pediatric. Following administration of 10 to 75-mg/m2 doses of doxorubicin to 60 children and adolescents ranging from 2 months to 20 years of age, doxorubicin clearance averaged 1443 ± 114 mL/min/m2. Further analysis demonstrated that clearance in 52 children greater than 2 years of age (1540 mL/min/m2) was increased compared with adults. However, clearance in infants younger than 2 years of age (813 mL/min/m2) was decreased compared with older children and approached the range of clearance values determined in adults.
Geriatric. While the pharmacokinetics of elderly subjects (65 years of age) have been evaluated, no dosage adjustment is recommended based on age (see PRECAUTIONS, Geriatric Use).
Gender. A published clinical study involving 6 men and 21 women with no prior anthracycline therapy reported a significantly higher median doxorubicin clearance in the men compared to the women (1088 mL/min/m2 versus 433 mL/min/m2). However, the terminal half-life of doxorubicin was longer in men compared to the women (54 versus 35 hours).
Race. The influence of race on the pharmacokinetics of doxorubicin has not been evaluated.
Hepatic Impairment. The clearance of doxorubicin and doxorubicinol was reduced in patients with impaired hepatic function (see DOSAGE AND ADMINISTRATION).
Renal Impairment. The influence of renal function on the pharmacokinetics of doxorubicin has not been evaluated.
All MedLibrary.org resources are included in as near-original form as possible, meaning that the information from the original provider has been rendered here with only typographical or stylistic modifications and not with any substantive alterations of content, meaning or intent.