Given the difference in pharmacokinetic profiles and dosing schedules, doxorubicin should not be used interchangeably with other formulations of doxorubicin hydrochloride.
Cardiac toxicity: It is recommended that all patients receiving Doxorubicin routinely undergo frequent ECG monitoring. Transient ECG changes such as T-wave flattening, S-T segment depression and benign arrhythmias are not considered mandatory indications for the suspension of Doxorubicin therapy. However, reduction of the QRS complex is considered more indicative of cardiac toxicity. If this change occurs, the most definitive test for anthracycline myocardial injury, i.e., endomyocardial biopsy, must be considered.
More specific methods for the evaluation and monitoring of cardiac functions as compared to ECG are a measurement of left ventricular ejection fraction by echocardiography or preferably by Multigated Angiography (MUGA). These methods must be applied routinely before the initiation of Doxorubicin therapy and repeated periodically during treatment. The evaluation of left ventricular function is considered to be mandatory before each additional administration of Doxorubicin that exceeds a lifetime cumulative anthracycline dose of 450 mg/m2.
The evaluation tests and methods mentioned previously concerning the monitoring of cardiac performance during anthracycline therapy are to be employed in the following order: ECG monitoring, measurement of left ventricular ejection fraction, endomyocardial biopsy. If a test result indicates possible cardiac injury associated with Doxorubicin therapy, the benefit of continued therapy must be carefully weighed against the risk of myocardial injury.
In patients with cardiac disease requiring treatment, administer doxorubicin only when the benefit outweighs the risk to the patient.
Exercise caution in patients with impaired cardiac function who receive Doxorubicin. Whenever cardiomyopathy is suspected, i.e., the left ventricular ejection fraction has substantially decreased relative to pre-treatment values and/or left ventricular ejection fraction is lower than a prognostically relevant value, endomyocardial biopsy may be considered and the benefit of continued therapy must be carefully evaluated against the risk of developing irreversible cardiac damage.
Congestive heart failure due to cardiomyopathy may occur suddenly, without prior ECG changes and may also be encountered several weeks after discontinuation of therapy.
Caution must be observed in patients who have received other anthracyclines. The total dose of doxorubicin hydrochloride must also take into account any previous (or concomitant) therapy with cardiotoxic compounds such as other anthracyclines/anthraquinones or e.g., 5-fluorouracil. Cardiac toxicity also may occur at cumulative anthracycline doses lower than 450 mg/m2 in patients with prior mediastinal irradiation or in those receiving concurrent cyclophosphamide therapy.
The cardiac safety profile for the dosing schedule recommended for both breast and ovarian cancer (50 mg/m2) is similar to the 20 mg/m2 profile in patients with AIDS-KS.
Myelosuppression: Many patients treated with Doxorubicin have baseline myelosuppression due to such factors as their pre-existing HIV disease or numerous concomitant or previous medications, or tumours involving bone marrow. Myelosuppression was generally mild to moderate, reversible, and was not associated with episodes of neutropaenic infection or sepsis in patients with ovarian cancer treated at a dose of 50 mg/m2. Myelosuppression appears to be the dose-limiting adverse event in patients with AIDS-KS, breast cancer or ovarian cancer. Because of the potential for bone marrow suppression, periodic blood counts must be performed frequently during the course of Doxorubicin therapy, and at a minimum, prior to each dose of Doxorubicin.
Persistent severe myelosuppression, may result in superinfection or haemorrhage.
In patients with AIDS-KS against a bleomycin/vincristine regimen, opportunistic infections were apparently more frequent during treatment with Doxorubicin. Patients and doctors must be aware of this higher incidence and take action as appropriate.
Secondary haematological malignancies: As with other DNA-damaging antineoplastic agents, secondary acute myeloid leukemias and myelodysplasias have been reported in patients having received combined treatment with doxorubicin. Therefore, any patient treated with doxorubicin should be kept under haematological supervision.
Secondary oral neoplasms: Very rare cases of secondary oral cancer have been reported in patients with long-term (more than one year) exposure to Doxorubicin or those receiving a cumulative Doxorubicin dose greater than 720 mg/m2. Cases of secondary oral cancer were diagnosed both, during treatment with Doxorubicin, and up to 6 years after the last dose. Patients should be examined at regular intervals for the presence of oral ulceration or any oral discomfort that may be indicative of secondary oral cancer.
Infusion-associated reactions: Serious and sometimes life-threatening infusion reactions, which are characterised by allergic-like or anaphylactoid-like reactions, with symptoms including asthma, flushing, urticarial rash, chest pain, fever, hypertension, tachycardia, pruritus, sweating, shortness of breath, facial edema, chills, and back pain, tightness in the chest and throat and/or hypotension may occur within minutes of starting the infusion of Doxorubicin. Very rarely, convulsions also have been observed in relation to infusion reactions. Temporarily stopping the infusion usually resolves these symptoms without further therapy. However, medications to treat these symptoms (e.g., antihistamines, corticosteroids, adrenaline, and anticonvulsants), as well as emergency equipment should be available for immediate use. In most patients treatment can be resumed after all symptoms have resolved, without recurrence. Infusion reactions rarely recur after the first treatment cycle. To minimise the risk of infusion reactions, the initial dose should be administered at a rate no greater than 1 mg/minute.
Diabetic patients: Please note that each vial of Doxorubicin contains sucrose and the dose is administered in 5% (50 mg/ml) glucose solution for infusion.
Effects on ability to drive and use machines: Doxorubicin has no or negligible influence on the ability to drive and use machines. Dizziness and somnolence were associated infrequently with the administration of Doxorubicin. Patients who suffer from these effects must avoid driving and operating machinery.