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Home > Drug Category > Cancer Medications > Ibrance and Equivalent

Ibrance (Palbociclib) Information

Ibrance, which contains the active ingredient palbociclib, is a targeted therapy medication classified as a CDK4/6 inhibitor. It is primarily used to treat adults with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer. Ibrance is administered in combination with an aromatase inhibitor (such as letrozole) as initial endocrine-based therapy, or with fulvestrant in patients whose disease has progressed following endocrine therapy. By slowing the spread of cancer cells, Ibrance helps delay disease progression and improve clinical outcomes. It is taken by mouth, usually once daily as a capsule or tablet.

The mechanism of action involves the selective inhibition of cyclin-dependent kinases 4 and 6 (CDK4/6). These specific proteins are responsible for signaling a cell to divide and multiply. In many HR-positive breast cancers, these kinases become overactive, leading to the rapid and uncontrolled growth of tumors. Ibrance works by blocking these proteins, halting the cell cycle, and preventing cancer cells from progressing from the resting phase into the division phase, effectively slowing or stopping tumor growth.

Ibrance Side Effects

Ibrance is generally well-tolerated, but common side effects may occur as your body adjusts to the medication. Commonly reported effects include fatigue, nausea, diarrhea, thinning hair (alopecia), mouth sores, and a decreased appetite. Because the medication also affects the production of healthy blood cells, many patients develop anemia (low red blood cell count), which can cause weakness or shortness of breath.

More serious side effects can occur and require immediate medical attention. Stop taking the medication and seek help if you experience:
• Blood Clots: Pain or swelling in an arm or leg, sudden chest pain, or rapid breathing, which may indicate a pulmonary embolism or deep vein thrombosis.
• Liver Toxicity: Yellowing of the eyes or skin (jaundice), dark urine, or pain in the right side of the stomach area.
• Lung Inflammation (Pneumonitis): New or worsening respiratory symptoms, such as trouble breathing, cough, or chest pain.
• Severe Neutropenia: Fever, chills, or any other signs of infection, as a low white blood cell count is the most common serious side effect and can be life-threatening.

Ibrance Precautions

Do not use Ibrance if you have a known allergy to palbociclib or any of the inactive ingredients in the medication. Before starting treatment, inform your doctor of your complete medical history, especially if you have a history of liver or kidney disease or any active infections. Because Ibrance can significantly lower your white blood cell count, your doctor will order blood tests before each treatment cycle and on Day 15 of the first two cycles. Tell your doctor about all medications you take, as Ibrance has significant drug interactions. Its effectiveness can be reduced by strong CYP3A inducers, such as the herbal supplement St. John’s Wort or certain anti-seizure medications. Conversely, strong CYP3A inhibitors, such as certain antifungal drugs or antibiotics, can increase the levels of Ibrance in your blood to a toxic range. You must avoid grapefruit and grapefruit products, as they can interfere with the way your body processes the drug. Also, discuss any other supplements or over-the-counter medications with your oncologist to ensure they are safe to use during your cycle.

Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding. Ibrance can cause fetal harm. Do not use this medicine during pregnancy. Women of reproductive potential should use effective contraception during treatment and for at least 3 weeks after the last dose; men with female partners of reproductive potential should also use effective contraception for 3 months after the final dose. Ibrance may also decrease fertility in men; discuss sperm preservation with your doctor if this is a concern. Avoid breastfeeding while taking Ibrance and for at least 3 weeks after the final dose.

Take Ibrance exactly as prescribed by your doctor. Ibrance is typically taken in cycles: one dose daily for 21 days followed by 7 days off to allow your blood counts to recover. Take the capsules with food to ensure consistent absorption. Taking the capsule on an empty stomach can significantly reduce the drug's effectiveness. You can take the tablets with or without food. Swallow both the tablets and capsules whole. Do not crush, chew, or open them. If you miss a dose or vomit after taking one, do not take an extra dose that day; wait and take your next dose at your regular time. Store the medication at room temperature in its original container.

Do I need a prescription to order Ibrance?

Yes, a prescription is required from your physician to order Ibrance.