Ixabepilone

Microtubule inhibitors
Microtubule inhibitors
High alert
An error with this medicine can cause serious harm: double checks and protocols are used.
Pregnancy: avoid
Avoid in pregnancy. May harm the fetus; a pregnancy test may be done, women and men with partners who could become pregnant use contraception for months after the last dose, and…

Epothilone that stabilises microtubules at the taxane site and resists efflux pumps. For metastatic breast cancer after anthracyclines and taxanes.

Updated Nov 1, 2026

Quick facts

Group: Microtubule inhibitors
Target: β-tubulin (taxane site, inside the microtubule)
Key effects: Tiredness and weakness · Hair loss · Nausea
Monitor: Liver tests before and during treatment
ATC: L01DC04

No doses: the clinician sets them by the current guideline.

Mechanism of action

β-tubulin (taxane site, inside the microtubule)Ixabepilone

The crystal shows ixabepilone bound to pig α/β-tubulin.

Target in 3D: β-tubulin (taxane site, inside the microtubule). PDB structure 7DAF (RCSB PDB, public domain). View the structure at RCSB PDB

The epothilones are polyketides first found in a soil myxobacterium, Sorangium cellulosum; ixabepilone is an analogue of epothilone B. It binds the taxane pocket on β-tubulin, on the inner side of the microtubule, and over-stabilises microtubules, which can even form away from the centrosome. The faulty spindle stops the cell at G2/M and it dies by apoptosis. It is less affected by P-glycoprotein efflux than the taxanes.

Ixabepilone binds the taxane site on β-tubulin
Microtubules become over-stable and disorganised
The cell arrests in G2/M and dies

Indications

Metastatic breast cancer resistant to anthracyclines and taxanes, with capecitabine; or alone after anthracyclines, taxanes and capecitabine. Breast cancer →

Adverse effects

Common

Tiredness and weakness
Hair loss, nail changes, darker or flaky skin
Nausea, vomiting, diarrhoea, mouth sores, taste change
Joint, muscle and bone pain
Drowsiness from the alcohol in the solvent

Contraindications

Combination with capecitabine in people with liver impairment

Key interactions

St John's wort: Interacts with ixabepilone and is not started during treatment without medical advice.
Capecitabine: Intended combination, but fatal toxicity occurs if the liver is impaired; liver tests come first.
Alcohol and sedating medicines: Add to the drowsiness from the alcohol in the infusion.

What is monitored

Liver tests before and during treatment
Blood count before each cycle
Signs of neuropathy, especially in diabetes
Vital signs during the infusion

Administration and safety

Premedication with an H1 and an H2 antagonist before each infusion to prevent hypersensitivity.
Powder mixed with liquid and infused intravenously over about three hours.
The patient should not drive after the infusion until the effect of the alcohol is known.
Hazardous drug: prepared and disposed of under cytotoxic-drug procedures.

Pregnancy and breastfeeding

Avoid in pregnancy. May harm the fetus; a pregnancy test may be done, women and men with partners who could become pregnant use contraception for months after the last dose, and it may reduce fertility.

Nursing care

Confirm liver test results before each cycle, especially with capecitabine.
Ask about diabetes, existing neuropathy and heart disease.
Watch for flushing, rash, swelling or breathlessness during the infusion.
Teach to report numbness or tingling, fever, red painful palms or soles, and chest pain.

Pharmacokinetics

Absorption: Intravenous infusion over about three hours; it is poorly water-soluble and comes in a polyoxyethylated castor oil and ethanol solvent.
Metabolism: Cleared by liver CYP enzymes; St John's wort and grapefruit can change its levels.
Half-life: About 52 hours.

Test yourself

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

Where does ixabepilone bind tubulin?

At the taxane site on β-tubulin, on the inner side of the microtubule.

Why must liver function be checked before ixabepilone with capecitabine?

The combination can cause fatal toxicity in people with liver impairment.

Which premedication is given before ixabepilone, and why?

An H1 and an H2 antagonist, to prevent hypersensitivity reactions to its solvent.

Add to my cards (3)

Connections

← Back to the class: Microtubule 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: Ixabepilone Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); IXA in complex with tubulin (RCSB Protein Data Bank, 2021).

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Representative model, for educational purposes only.