It’s important to know that women who are pregnant or planning to get pregnant should not take Verzenio. Verzenio can harm the developing fetus. It’s important that you don’t get pregnant while taking Verzenio; if there is any chance you can become pregnant, you must use effective birth control while you’re taking Verzenio and for at least 3 weeks after your last dose.
Also, women who are breastfeeding or plan to breastfeed shouldn’t take Verzenio. Together, you and your doctor will decide if you should take Verzenio or breastfeed.
The most common side effects of Verzenio are:
- low white blood cell counts (neutropenia and leukopenia)
- abdominal pain
- low red blood cell counts (anemia)
- decreased appetite
- low platelet counts (thrombocytopenia)
Verzenio also may cause serious side effects, including:
Diarrhea: Diarrhea is a common side effect of Verzenio. Still, some women may have such severe diarrhea that they have to decrease the dose of Verzenio or stop treatment. Tell your doctor immediately if you have any diarrhea.
Liver problems: Tell your doctor right away if you have any of the following signs of liver problems:
- yellowing of the skin or the whites of the eyes
- dark or brown urine
- feeling very tired
- loss of appetite
- pain on the upper right side of the abdomen
- bleeding or bruising more easily than normal
Neutropenia (low white blood cell count): Low white blood cell counts are a common side effect of Verzenio. Still, some women’s white blood cell counts may drop so low that they have to decrease the dose of Verzenio or stop treatment. Your doctor will check your white blood cell count before and during treatment with Verzenio.
Blood clots: Verzenio may cause serious or life-threatening blood clots in your arteries or lungs. Tell your doctor right away if you have shortness of breath, rapid heart rate, rapid breathing, or a sudden sharp chest pain.
Because Verzenio is given with Faslodex or an aromatase inhibitor, you also may have side effects caused by those medicines. Common side effects of Faslodex are hot flashes, nausea, and vomiting. Common side effects of an aromatase inhibitor are joint stiffness and joint pain.