Pronunciation: pall-bow-see-clib
Generic name: palbociclib
Brand name: Ibrance
Dosage form: oral tablet, oral capsule
Drug class: CDK 4/6 inhibitors

Medically reviewed by Carmen Pope, BPharm. Last updated on Oct 7, 2024.

What is palbociclib?

Palbociclib (brand name Ibrance) may be used to treat adults with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer that has spread to other parts of the body (metastatic) in combination with an aromatase inhibitor as the first hormonal based therapy, or fulvestrant in those with breast cancer progression following hormonal therapy.

Palbociclib's mechanism of action involves blocking proteins involved in cell division called cyclin-dependent kinases (CDK), specifically CDK 4 and 6. By blocking these proteins, palbociclib prevents cancer cells from dividing and multiplying uncontrollably. HR+ breast cancer cells rely heavily on CDK 4/6 for growth. Palbociclib is not chemotherapy it is a targeted treatment (see: Is Ibrance a form of chemo? for more information).

Palbociclib gained FDA approval on February 3, 2015, under the brand Ibrance. An Ibrance generic is available (see generic Ibrance availability).

Palbociclib uses

Palbociclib is used to treat adult patients with HR-positive, HER2-negative advanced or metastatic breast cancer. It should always be used in combination with another medicine either:

• an aromatase inhibitor (such as anastrozole, exemestane, or letrozole) as initial endocrine-based therapy in postmenopausal women or in men; or
• fulvestrant in patients with disease progression following endocrine therapy.

Palbociclib side effects

The most common side effects of palbociclib are:

• infections
• tiredness
• nausea
• sore mouth
• abnormalities in liver blood tests
• diarrhea
• hair thinning or hair loss
• vomiting
• rash
• loss of appetite
• low red blood cell counts and low platelet counts. Call your healthcare provider right away if you develop any of these symptoms of low blood cell  during treatment dizziness, shortness of breath, weakness, bleeding or bruising more easily, or nosebleeds

These palbociclib side effects are the most common that occur when used with either letrozole or fulvestrant.

Palbociclib may cause fertility problems in males. This may affect your ability to father a child. Talk to your healthcare provider about family planning options before starting Palbociclib if this is a concern for you.

Serious side effects and warnings

Palbociclib may cause the following serious side effects.

Low white blood cell counts (neutropenia). Low white blood cell counts are very common when taking palbociclib and may cause serious infections that can lead to death. Your healthcare provider should check your white blood cell counts before and during treatment.

If you develop low white blood cell counts during treatment with palbociclib, your healthcare provider may stop your treatment, decrease your dose, or tell you to wait to begin your treatment cycle. Tell your healthcare provider right away if you have signs and symptoms of low white blood cell counts or infections such as fever and chills.

Lung problems (pneumonitis). Palbociclib may cause severe or life-threatening inflammation of the lungs during treatment that can lead to death. Tell your healthcare provider right away if you have any new or worsening symptoms, including:

• chest pain
• cough with or without mucus
• trouble breathing or shortness of breath.

Your healthcare provider may interrupt or stop treatment with palbociclib completely if your symptoms are severe.

It is not known if palbociclib is safe and effective in children.

Tell your healthcare provider if you have any side effect that bothers you or does not go away. These are not all of the possible side effects of palbociclib. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before taking

Before taking palbociclib, tell your healthcare provider about all of your medical conditions, including if you:

• have fever, chills, or any other signs or symptoms of infection
• have liver or kidney problems
• have any other medical conditions
• are pregnant, or plan to become pregnant
• are breastfeeding or plan to breastfeed

Pregnancy

Palbociclib can harm your unborn baby. Females who can become pregnant should use effective birth control during treatment and for at least 3 weeks after the last dose of palbociclib. Your healthcare provider may ask you to take a pregnancy test before you start treatment with palbociclib.

Males with female partners who can become pregnant should use effective birth control during treatment with palbociclib for at least 3 months after the last dose of palbociclib. Talk to your healthcare provider about birth control methods that may be right for you during this time.

If you become pregnant or think you are pregnant, tell your healthcare provider right away.

Breastfeeding

It is not known if palbociclib passes into your breast milk. Do not breastfeed during treatment with palbociclib and for 3 weeks after the last dose.

How should I take palbociclib?

Take palbociclib exactly as your healthcare provider tells you.

• Take palbociclib with or without food.
• Palbociclib should be taken at about the same time each day.
• Swallow palbociclib capsules or tablets whole. Do not chew or crush the capsules or tablets and do not try to open the capsules before swallowing them.
• Do not take any palbociclib capsules or tablets that are broken, cracked, or that look damaged.

Avoid grapefruit and grapefruit products during treatment with palbociclib. Grapefruit may increase the amount of palbociclib in your blood.

Do not change your dose or stop taking palbociclib unless your healthcare provider tells you.

Palbociclib dosing

The recommended palbociclib starting dose for breast cancer is palbociclib 125 mg 1 time daily with or without food for 21 days followed by 7 days without treatment.

• Your healthcare provider may adjust your dose based on how well you tolerate palbociclib.
• This dose of palbociclib is taken in combination with an aromatase inhibitor or fulvestrant.  

What happens if I miss a dose?

If you miss a dose of palbociclib or vomit after taking a dose of palbociclib, do not take another dose on that day. Take your next dose at your regular time.

What happens if I take too much palbociclib?

If you take too much palbociclib, call your healthcare provider right away or go to the nearest hospital emergency room.

What other drugs will affect palbociclib?

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Palbociclib and other medicines may affect each other causing side effects. Especially tell your healthcare provider if you take:

• CYP3A Inhibitors, such as clarithromycin, diltiazem, erythromycin, fluconazole, ketoconazole, or verapamil. These should not be taken at the same time as palbociclib. If a strong CYP3A inhibitor cannot be avoided, your healthcare provider should reduce the dose of palbociclib
• CYP3A Inducers, such as glucocorticoids, rifampin, carbamazepine, phenobarbital, and phenytoin. Avoid using these at the same time as palbociclib
• Cyp3A substrates, such as cyclosporin, tricyclic antidepressants, and some chemotherapy agents. The dose of sensitive CYP3A4 substrates with narrow therapeutic indices may need to be reduced when given concurrently with palbociclib.

Avoid grapefruit and grapefruit products.

Know the medicines you take. Keep a list of them to show your healthcare provider or pharmacist when you get a new medicine. This is not a full list of interactions with palbociclib. See the palbociclib prescribing information for a complete list.

How should I store palbociclib?

Store palbociclib at 68 °F to 77 °F (20 °C to 25 °C) in the original blister pack.

Keep out of the reach of children.

Palbociclib ingredients

Palbociclib is available as a generic and under the brand name Ibrance.

Active ingredient: palbociclib

Ibrance inactive ingredients: microcrystalline cellulose, colloidal silicon dioxide, crospovidone, magnesium stearate, succinic acid, HPMC 2910/hypromellose, titanium dioxide, triacetin, and FD&C Blue #2/Indigo Carmine Aluminum Lake. In addition, the 75 mg and 125 mg tablets contain red iron oxide and the 100 mg tablets contain yellow iron oxide.

Who makes palbociclib?

Pfizer Labs makes palbociclib under the brand name Ibrance.

Synthon Pharms Inc. makes a generic palbociclib tablet but a generic palbociclib capsule is not available yet.

Popular FAQ

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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