Canol Infusion

Indications

• Ovarian cancer
• Small cell lung cancer
• Other solid tumors as determined by oncologist

Dosage

Children: Refer to the latest clinical guidelines and BNF for Children for specific dosing information.

Adults: Refer to the latest clinical guidelines and BNF for specific dosing information.

Mechanism of action

Topotecan exerts its therapeutic effects by inhibiting the enzyme topoisomerase I, which is essential for DNA replication. By binding to the topoisomerase I-DNA complex, topotecan prevents the re-ligation of DNA strands after they have been cleaved, resulting in the accumulation of single-strand breaks in the DNA. This accumulation ultimately triggers apoptosis (programmed cell death) in cancer cells.

Pharmacodynamics

Topotecan demonstrates a concentration-dependent cytotoxic effect on cancer cells. The drug's efficacy is influenced by the duration and intensity of drug exposure, with higher doses leading to increased cell death. The drug has a unique mechanism that specifically targets proliferating cells, making it effective against rapidly dividing tumors. Resistance mechanisms may include increased drug efflux, alterations in topoisomerase I expression, and enhanced DNA repair mechanisms.

Pharmacokinetics

Topotecan is administered intravenously, and its pharmacokinetics are characterized by a rapid distribution phase followed by a slower elimination phase. The drug is metabolized primarily in the liver through oxidation and glucuronidation. The elimination half-life ranges from 2 to 3 hours, with renal excretion being the main route of elimination. Dose adjustments may be necessary in patients with renal impairment due to the potential for increased drug exposure.

Contra-indications

• Hypersensitivity to topotecan or any of its components
• Severe bone marrow suppression
• Pregnancy

Adverse effects

• Myelosuppression leading to neutropenia, anemia, and thrombocytopenia
• Nausea and vomiting
• Diarrhea
• Fatigue
• Mucositis
• Alopecia
• Infection due to immunosuppression

Interactions

• Caution with other agents that cause myelosuppression
• Potential interactions with other chemotherapeutic agents
• Drugs that affect hepatic enzymes may alter metabolism

Precautions

• Monitor blood counts regularly due to risk of myelosuppression
• Use with caution in patients with renal impairment
• Hydration is important to minimize renal toxicity
• Avoid live vaccines during treatment

Pregnancy

Topotecan is classified as pregnancy category D, indicating potential harm to the fetus.

Breast-feeding

It is unknown whether topotecan is excreted in human milk; caution is advised.

Storage

Store at room temperature, away from light and moisture. Do not freeze.

Formulations

• Topotecan hydrochloride injection
• Topotecan capsules