[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Topoisomerase inhibitors](https://durgical.com/en/pharmacology/classes/topoisomerase-inhibitors/) › Topotecan

[Pharmacology](https://durgical.com/en/pharmacology/) · [Topoisomerase inhibitors](https://durgical.com/en/pharmacology/classes/topoisomerase-inhibitors/)

# Topotecan

A camptothecin that traps topoisomerase I. Used in relapsed ovarian and small cell lung cancer and in cervical cancer; severe myelosuppression is its main risk.

Updated 2026-11-01

- Class: [Topoisomerase inhibitors](https://durgical.com/en/pharmacology/classes/topoisomerase-inhibitors/)
- Enzyme: DNA topoisomerase I
- ATC code: L01CE01

## ⚠ High-alert medication

An error with this medicine can cause serious harm: double checks and protocols are used.

✂**DNA topoisomerase I**Topotecan

ⓘ The crystal shows topotecan stacked between DNA base pairs at the cut site of human topoisomerase I.

**Target in 3D:** DNA topoisomerase I. PDB structure 1K4T (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1K4T) · Drag to rotate · pinch to zoom

## Mechanism of action

Topotecan binds the topoisomerase I–DNA complex and prevents religation of the single-strand break. Replication enzymes running into the trapped complex create double-strand DNA damage, which mammalian cells cannot repair efficiently.

- Topotecan binds the topoisomerase I–DNA complex
- The single-strand nick is not resealed
- Replication turns it into a double-strand break

## Pharmacokinetics

**Absorption**
Intravenous infusion.

**Distribution**
About a third is bound to plasma proteins.

**Metabolism**
Its active lactone ring opens reversibly, depending on pH, to an inactive hydroxy-acid form.

**Elimination**
Mainly in the urine; the dose is reduced in kidney impairment.

**Half-life**
About 2 to 3 hours.

## Indications

- Metastatic ovarian cancer after progression on earlier chemotherapy. [Ovarian cancer →](https://durgical.com/en/conditions/ovarian-cancer/)
- Small cell lung cancer, platinum-sensitive disease that relapses. [Lung cancer →](https://durgical.com/en/conditions/lung-cancer/)
- Stage IV-B, recurrent or persistent cervical cancer, with cisplatin. [Cervical cancer →](https://durgical.com/en/conditions/cervical-cancer/)

## Adverse effects

### Common

- Neutropenia, thrombocytopenia and anaemia
- Nausea, vomiting and diarrhoea
- Fatigue and breathlessness

### Serious (rare, important)

- Severe myelosuppression with sepsis (boxed warning)
- Neutropenic enterocolitis (typhlitis), which can be fatal
- Interstitial lung disease
- Severe extravasation injury

## Contraindications

- History of severe hypersensitivity to topotecan
- The first cycle is not given unless neutrophils and platelets are adequate

## Key interactions

**Cisplatin**
Used together in cervical cancer; marrow suppression adds up, including severe anaemia.

**Other myelosuppressive drugs or radiotherapy**
Additive bone-marrow toxicity.

## What is monitored

- Blood counts frequently during each cycle
- Kidney function (dose adjustment)
- Fever with abdominal pain (typhlitis) and respiratory symptoms

## Administration and safety

- Given as an intravenous infusion; the site is watched, and extravasation is stopped and managed at once.
- Kidney function is checked before preparation, because the dose depends on it.
- Hazardous drug: prepared and given following hazardous-drug handling procedures (impervious gloves, no skin contact) and disposed of as cytotoxic waste.

## Nursing care

- Independent double check of drug, patient, route and cycle before giving it (high-alert medicine).
- Confirm adequate neutrophils and platelets before each cycle.
- Report fever with abdominal pain at once (neutropenic enterocolitis).
- Teaching: report fever, chills, sore throat, bleeding or bruising at once.

## Pregnancy and breastfeeding

Can cause fetal harm (embryolethal and teratogenic in animals); effective contraception is used during treatment.

## Memory aid

TOPOtecan and irinotecan both end in «-tecan»: «TEC» for «Topo I, Every Cut stays open». Topotecan hits the marrow; irinotecan hits the bowel.

## Test yourself

Think of the answer, then tap the question to see it.

## Which enzyme does topotecan inhibit?

Topoisomerase I.

## What is the boxed warning for topotecan?

Severe myelosuppression; the first cycle is given only with adequate baseline neutrophils and platelets.

## Why is the topotecan dose reduced in kidney impairment?

It is eliminated mainly in the urine, so exposure and marrow toxicity rise.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/topotecan/)

## Related drugs

- [Irinotecan](https://durgical.com/en/pharmacology/irinotecan/)
- [Etoposide](https://durgical.com/en/pharmacology/etoposide/)
- [Cisplatin](https://durgical.com/en/pharmacology/cisplatin/)

## Related conditions

- [Ovarian cancer](https://durgical.com/en/conditions/ovarian-cancer/)
- [Lung cancer](https://durgical.com/en/conditions/lung-cancer/)
- [Cervical cancer](https://durgical.com/en/conditions/cervical-cancer/)

[← Back to the class: Topoisomerase inhibitors](https://durgical.com/en/pharmacology/classes/topoisomerase-inhibitors/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - TOPOTECAN HYDROCHLORIDE injection, powder, lyophilized, for solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b6019088-cd94-43b4-b5ce-ba20b6b8021e) (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 70 (McGraw Hill, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L01CE01) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/topotecan/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/topotecan/