1. Clinical Overview
Doxorubicin (Liposomal) is a pegylated, liposome-encapsulated formulation of the anthracycline antibiotic doxorubicin. This formulation is designed to enhance drug delivery to tumor sites while reducing systemic exposure and certain toxicities, most notably cardiotoxicity and palmar-plantar erythrodysesthesia (hand-foot syndrome), compared to conventional doxorubicin. It represents a critical chemotherapeutic agent in the Indian oncology landscape.
| Onset | Duration | Bioavailability |
|---|---|---|
| Cytotoxic effects begin upon cellular uptake, but clinical tumor response typically takes several weeks to manifest. | The cytotoxic effect is prolonged due to sustained release from liposomes. Pharmacological effects persist for weeks, correlating with its long terminal half-life. | Not applicable as it is administered intravenously, achieving 100% systemic bioavailability. |
2. Mechanism of Action
The liposomal formulation delivers doxorubicin to tumor sites via the Enhanced Permeability and Retention (EPR) effect. Once internalized by tumor cells and doxorubicin is released, it intercalates into DNA base pairs, causing uncoiling of the DNA helix. This inhibits the progression of the enzyme topoisomerase II, which is required for DNA replication and repair, leading to DNA strand breaks and inhibition of nucleic acid synthesis.
3. Indications & Uses
- AIDS-related Kaposi's sarcoma (in patients with low CD4 counts and extensive mucocutaneous disease)
- Ovarian cancer (platinum-refractory)
- Multiple myeloma (in combination with bortezomib for patients who have not previously received bortezomib and have received at least one prior therapy)
4. Dosage & Administration
Adult Dosage: Dose is based on body surface area (BSA). **AIDS-KS:** 20 mg/m² IV over 30 minutes every 2-3 weeks. **Ovarian Cancer:** 50 mg/m² IV over 60 minutes every 4 weeks. **Multiple Myeloma:** 30 mg/m² IV over 60 minutes on day 4 following bortezomib (which is given on days 1, 4, 8, & 11 of a 21-day cycle).
Administration: FOR INTRAVENOUS INFUSION ONLY. MUST NOT BE GIVEN INTRAMUSCULARLY OR SUBCUTANEOUSLY. Do not mix with other drugs. Dilute in 250 mL of 5% Dextrose Injection (preferred) to minimize aggregation. Do not use saline or any other diluent. Administer using a dedicated IV line at a controlled rate (as per indication) using an infusion pump. Observe for extravasation, which can cause severe local tissue damage.
5. Side Effects
Common side effects may include:
- Myelosuppression (Neutropenia, Leukopenia, Anemia, Thrombocytopenia)
- Nausea and Vomiting (less severe than conventional doxorubicin)
- Stomatitis/Mucositis
- Alopecia (reversible, less frequent than conventional)
- Fatigue/Asthenia
- Palmar-Plantar Erythrodysesthesia (Hand-Foot Syndrome) - dose limiting
- Diarrhea or Constipation
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Trastuzumab, Cyclophosphamide | Markedly increased risk of cardiotoxicity (congestive heart failure, decreased LVEF). | Major |
| Other Myelosuppressive Agents (e.g., Paclitaxel, Gemcitabine) | Additive bone marrow suppression. Monitor blood counts closely. | Major |
| Phenobarbital, Phenytoin | Increased hepatic metabolism of doxorubicin, potentially reducing its efficacy. | Moderate |
| Live Vaccines (e.g., MMR, Varicella) | Risk of disseminated infection due to immunosuppression. Avoid. | Major |
| Dexrazoxane | Cardioprotective agent used to reduce the risk of doxorubicin-induced cardiomyopathy. | Beneficial Interaction |
7. Patient Counselling
- DO report any signs of infection (fever, chills, sore throat) immediately.
- DO maintain good oral hygiene to reduce risk of mucositis.
- DO use effective contraception during and for ≥6 months after therapy.
- DO keep the infusion site clean and report any pain, redness, or swelling during/after infusion.
- DONT receive any live vaccinations without consulting your oncologist.
- DONT consume grapefruit or its juice during therapy.
- DONT try to conceive or father a child during treatment.
8. Toxicology & Storage
Overdose: Exacerbation of acute toxicities: Severe myelosuppression (pancytopenia, infection, hemorrhage), severe mucositis, gastrointestinal toxicity, and acute cardiotoxicity (pericarditis, myocarditis, arrhythmias).
Storage: Store unopened vials refrigerated at 2°C to 8°C. **DO NOT FREEZE.** Protect from light. The diluted solution in 5% Dextrose is stable for up to 24 hours under refrigeration (2°C-8°C). Do not use if there is evidence of particulate matter or discoloration. Discard any unused portion. Handle with care using appropriate cytotoxic drug handling precautions (gloves, gown, eye protection).