Abemaciclib

What is Abemaciclib?

Abemaciclib is a prescription cancer medicine. It belongs to a drug class called CDK4/6 inhibitors (cyclin-dependent kinase 4 and 6 inhibitors), a type of targeted therapy. It is sold under the brand name Verzenio.

Approved uses: In the United States, abemaciclib is approved for adults with hormone receptor-positive (HR+), HER2-negative breast cancer in these situations:

• Early breast cancer: Together with hormone (endocrine) therapy after surgery, for people whose cancer involves the lymph nodes and who are at high risk of the cancer coming back
• Advanced or metastatic breast cancer: Together with an aromatase inhibitor as a first hormone-based treatment, or together with fulvestrant after the cancer has grown during earlier hormone therapy
• Advanced or metastatic breast cancer, as a single medicine: After hormone therapy and earlier chemotherapy have been tried

Formulations and strengths: Abemaciclib is taken by mouth as tablets in 50 mg, 100 mg, 150 mg, and 200 mg strengths. Other uses should be discussed only with your oncologist.

What is the Recommended Dosage of Abemaciclib?

Your dose is set by your oncologist and should always follow their instructions and your pharmacy label. Abemaciclib tablets are swallowed whole, usually twice a day at about the same times each day, with or without food. Do not chew, crush, or split the tablets. Your care team will tell you exactly which strength to take and when.

Your care team may adjust the dose or schedule based on:

• Your condition and tolerance: Treatment may be paused or the dose lowered if side effects such as diarrhea, low blood counts, or liver changes occur.
• How it is being used: The dose can differ when abemaciclib is taken with hormone therapy compared with when it is taken alone.
• Liver function: People with severe liver impairment may take it less often.
• Kidney function: No routine change is needed for mild to moderate kidney problems. Severe kidney problems have not been well studied.
• Other medicines: Some drugs change how much abemaciclib is in your body.
• Overall health: Age and other conditions can matter.

Do not change, skip, or stop doses on your own. If you have trouble swallowing tablets, ask your care team or pharmacist for options.

How Abemaciclib Works

Healthy and cancer cells use proteins called CDK4 and CDK6 to move through the cell cycle, the process cells use to grow and divide. In some breast cancers, these proteins are overactive and help the cancer cells multiply.

Abemaciclib blocks CDK4 and CDK6, which can slow or stop cancer cells from dividing. When it is taken together with hormone therapy, the two medicines work in different ways on the same cancer. Abemaciclib is used to control the disease or lower the chance of it coming back, and it is not considered a cure. Regular scans, exams, and follow-up visits help your care team see how treatment is working.

Is a Prescription Required to Buy Abemaciclib Online?

Yes. Abemaciclib is prescription-only. It should be prescribed and monitored by a licensed medical oncologist (a cancer specialist), often a breast cancer specialist.

• Tests that confirm hormone receptor and HER2 status are needed to confirm that the medicine fits the cancer type.
• Buy only from a licensed pharmacy that requires a valid prescription.
• Counterfeit or substandard cancer medicines exist. Be cautious of websites that sell without a prescription or ship from unclear sources.
• Check that the tablets match what your pharmacist describes, and ask your pharmacist if packaging or appearance looks different.

Side Effects of Abemaciclib

Not everyone gets every side effect. Many can be managed with help from your care team.

Common Side Effects

• Diarrhea (often the most common, and usually early in treatment)
• Low white blood cell counts (neutropenia), which can raise infection risk
• Low red blood cell counts (anemia) and low platelets
• Nausea, vomiting, or stomach pain
• Decreased appetite
• Tiredness
• Infections, such as colds or urinary infections
• Headache
• Hair thinning
• Higher creatinine on blood tests, which may not mean kidney damage, but your team will review it
• Changes in liver blood tests

Serious Side Effects

These are less common but need prompt attention:

• Severe diarrhea: may lead to dehydration, dizziness, or kidney problems
• Serious infection or low white blood cell count: fever, chills, cough, sore throat, or burning with urination
• Lung problems (interstitial lung disease or pneumonitis): new or worsening cough, shortness of breath, or trouble breathing
• Liver problems: yellowing of the skin or eyes, dark urine, severe stomach pain, or unusual tiredness
• Blood clots: leg pain or swelling, sudden chest pain, or sudden shortness of breath

Seek immediate medical care if you have trouble breathing, chest pain, signs of a blood clot, or signs of severe dehydration. Contact your oncology team right away for a fever of 100.4°F (38°C) or higher, or for diarrhea that is severe or does not improve. Your care team may recommend starting an anti-diarrhea medicine at the first sign of loose stools and drinking extra fluids, so follow their instructions.

Drug Interactions

Tell your oncologist and pharmacist about everything you take, including prescription drugs, over-the-counter (OTC) products, vitamins, supplements, and herbal products. Major categories include:

• Strong CYP3A inhibitors (such as ketoconazole, itraconazole, clarithromycin) can raise abemaciclib levels and may increase side effects. Your care team may avoid these or lower your dose.
• CYP3A inducers (such as rifampin, carbamazepine, phenytoin) can lower abemaciclib levels and may make it less effective. These are generally avoided.
• Grapefruit and grapefruit juice may raise abemaciclib levels and are usually avoided.
• Herbal products, especially St. John’s wort, can lower abemaciclib levels. Ask your pharmacist before using any herbal or dietary supplement.
• Certain medicines cleared by the kidneys may be affected by abemaciclib’s effect on creatinine measurements. Your team will interpret lab results with this in mind.

Bring a complete, updated medication list to every appointment.

Safety & Important Considerations

• Blood counts: Blood tests are done before treatment, regularly in the first months, and then as needed. Dose changes may be needed if counts are low.
• Liver disease: Liver blood tests are checked before and during treatment. Dose changes or stopping the drug may be needed if problems arise.
• Kidney disease: Discuss any kidney problems with your specialist. Severe kidney impairment has not been well studied.
• Diarrhea and hydration: Diarrhea can become serious quickly. Keep an anti-diarrhea medicine on hand if your team recommends it, and report symptoms early.
• Lung symptoms: Report any new cough or breathing changes.
• Blood clots: Tell your team about any history of blood clots, as risk may be higher during treatment, especially when combined with hormone therapy.
• Pregnancy: Abemaciclib can harm an unborn baby. Effective contraception is advised during treatment and for at least 3 weeks after the last dose, according to U.S. labeling. Tell your oncologist right away if you are or may become pregnant.
• Fertility: Abemaciclib may affect fertility in males. Talk with your specialist if this is a concern.
• Breastfeeding: Breastfeeding is not recommended during treatment and for at least 3 weeks after the last dose.
• Older adults and children: Older adults may be monitored more closely. Safety and effectiveness in children have not been established.
• Monitoring: Expect regular visits, imaging scans, and blood tests.

Who This Medication Is For

Abemaciclib is intended for adults with HR-positive, HER2-negative breast cancer, either early-stage cancer at high risk of returning or advanced or metastatic cancer, as decided by their oncology team. Treatment plans differ from person to person.

Who Should Not Take Abemaciclib

U.S. labeling does not list formal contraindications for abemaciclib, but it is not suitable for everyone, and some people need extra caution.

Discuss with your oncologist before starting if you:

• Have had an allergic reaction to abemaciclib or any tablet ingredient
• Have an active infection or a history of frequent infections
• Have liver disease or severe kidney disease
• Have lung disease or breathing problems
• Have a history of blood clots
• Have ongoing diarrhea or other bowel problems
• Are pregnant, planning pregnancy, or breastfeeding
• Take medicines that interact with abemaciclib

What to Do If You Miss a Dose

• If you miss a dose or vomit after taking it, do not take an extra dose. Take your next dose at the usual time.
• Never take two doses at once to make up for a missed one.
• If you are unsure what to do, or you miss several doses, contact your oncology team or pharmacist.

Related medications to Abemaciclib

Other medicines are used for HR-positive, HER2-negative breast cancer, depending on the cancer’s stage and features and your health:

• Other CDK4/6 inhibitors: palbociclib and ribociclib
• Hormone-based treatments: aromatase inhibitors, tamoxifen, fulvestrant, and newer oral hormone therapies
• Other targeted medicines: everolimus, alpelisib, capivasertib, and others when specific gene changes are found
• Other approaches: chemotherapy, surgery, and radiation

These medicines differ in side effects, interactions, and approved uses. Switching or combining treatments must be decided together with your oncologist.

Storage Instructions

• Store at room temperature, about 68°F to 77°F (20°C to 25°C), with brief trips between 59°F and 86°F (15°C to 30°C) allowed.
• Keep tablets in the original container with the lid tightly closed, away from moisture (not in the bathroom) and light.
• Keep out of reach of children and pets.
• Do not use tablets past the expiration date. Ask your pharmacist about safe disposal of unused medicine.
• Caregivers handling the tablets should wash their hands afterward, and pregnant caregivers should ask the care team about handling precautions.

Disclaimer:

This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Patients must consult a licensed medical oncologist before starting, changing, or stopping treatment. Treatment decisions must be based on a full clinical evaluation by a qualified specialist.