Kisqali (ribociclib) is a brand-name prescription medication. It’s approved by the Food and Drug Administration (FDA) to treat certain types of breast cancer in adult females.*

Kisqali is typically used as a long-term treatment, in combination with certain hormone therapies for breast cancer.

Here are some fast facts about Kisqali:

  • Active ingredient: ribociclib
  • Drug class: CDK4/6 inhibitor (a type of targeted cancer therapy)
  • Drug form: oral tablet
  • FDA approval year: 2017

Like other drugs, Kisqali can cause side effects. Read on to learn about potential common, mild, and serious side effects. For a general overview of Kisqali, including details about its uses, see this article.

* Sex and gender exist on spectrums. Use of the term “female” in this article refers to sex assigned at birth.

Kisqali can cause certain side effects (also called adverse effects), some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Kisqali in clinical trials:

* For more information about this side effect, see “Side effect specifics” below.

Mild side effects can occur with Kisqali treatment. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Kisqali’s prescribing information.

Mild side effects that have been reported with Kisqali include:

These side effects may be temporary, lasting a few days to weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking Kisqali and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.

Kisqali may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Kisqali’s prescribing information.

If you develop serious side effects while taking Kisqali, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after using Kisqali. But it’s not clear whether this side effect occurred in clinical trials.

Kisqali may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

What are the side effects of treatment with Kisqali and Femara?

Side effects of treatment with Kisqali and Femara are similar to side effects of Kisqali when it’s used in combination with other hormone therapies for breast cancer. For details, see “Mild side effects of Kisqali” and “Serious side effects of Kisqali” above.

Clinical trials looked at Kisqali in combination with hormone therapies, including Femara (letrozole). Certain side effects were more common when Kisqali was taken in combination with Femara than with other hormone therapies. Examples of these side effects include:

Talk with your doctor about what to expect when Kisqali is taken in combination with Femara.

* For more information about this side effect, see “Side effect specifics” below.

Does Kisqali cause weight gain?

It’s not likely. Weight gain wasn’t reported in clinical trials of Kisqali.

Edema (swelling) is a less common side effect of Kisqali. And edema may lead to a small amount of weight gain. But as your swelling lessens, your weight should return to its normal range.

If you’re concerned about weight gain while taking Kisqali, talk with your doctor. They can advise on your risk for weight gain with Kisqali. And they can suggest ways to maintain a weight that’s healthy for you.

Learn more about some of the side effects that Kisqali may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Kisqali.

Fatigue

Fatigue may occur with Kisqali. This was one of the most common side effects in clinical trials of the drug.

Symptoms of fatigue can include:

What you can do

A few lifestyle changes may help you effectively manage fatigue. For example, drinking plenty of water, eating a well-balanced diet, and getting good quality sleep can help ease your symptoms.

If you’re concerned about fatigue with Kisqali, talk with your doctor. They can suggest other ways to manage this side effect.

Liver problems

Taking Kisqali can cause elevated liver enzymes (proteins). This was one of the more common side effects in clinical trials of the drug.

Elevated liver enzymes can be a sign of more serious liver problems. Watch for the following symptoms of liver problems while taking Kisqali:

What you can do

Before taking Kisqali, your doctor will recommend regular liver function tests. And they’ll keep checking your liver function periodically while you take the drug. If you develop elevated liver enzymes while taking Kisqali, your doctor may lower your dosage. Or they may prescribe a drug other than Kisqali for you.

If you already have liver problems, Kisqali may worsen your condition. Be sure to tell your doctor about any liver problems you have before taking Kisqali. They’ll recommend whether Kisqali is a treatment option for you.

Cardiac (heart) rhythm problems

Taking Kisqali may cause a certain heart rhythm problem. This side effect was rare in clinical trials of the drug.

Specifically, Kisqali may cause QT prolongation. This type of heart rhythm problem can be detected with an electrocardiogram (EKG).

Symptoms of this condition may include:

Your risk for this side effect is highest during the first month after you start Kisqali. Having abnormal electrolyte levels may increase your risk for heart problems as a side effect.

What you can do

Your doctor will likely check your electrolyte levels and give you an EKG before starting Kisqali. And they’ll keep checking these factors periodically while you’re taking the drug.

If your electrolyte levels are abnormal, your doctor may give you treatments to correct them before prescribing Kisqali.

If you develop a heart rhythm problem while taking Kisqali, your doctor may give you a lower dosage of the drug. Or they may prescribe a different treatment for you.

Tell your doctor if you have any symptoms of heart rhythm problems while taking Kisqali.

Allergic reaction

As with most drugs, Kisqali can cause an allergic reaction in some people. But it’s not clear whether this side effect occurred in clinical trials.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Kisqali. But if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Kisqali. This drug may not be the right treatment if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include:

Infection. Before starting treatment with Kisqali, tell your doctor about any infections you have. They’ll likely treat your infection before you start taking Kisqali.

Heart problems. Heart problems are a possible side effect of Kisqali. If you already have heart problems, you may have a higher risk of these side effects. Tell your doctor about any heart problems you have, including abnormal heart rhythm, slow heart rate, or a history of heart attack. They’ll help determine if Kisqali is a safe treatment option for you.

Liver problems. Kisqali can cause liver problems as a side effect, and the drug may not be safe for people with liver problems. Be sure to talk with your doctor about any liver problems you may have before starting treatment with Kisqali. They can help determine if Kisqali is right for you.

Abnormal electrolyte levels. Before taking Kisqali, tell your doctor if you have abnormal levels of any electrolytes. Be sure to tell them if you have problems with levels of magnesium, potassium, calcium, or phosphorus. Having abnormal electrolyte levels may increase your risk for heart problems as a side effect. Your doctor will check your electrolyte levels before starting Kisqali. And they’ll keep checking your electrolyte levels from time to time during treatment. If your electrolyte levels are abnormal, your doctor may give you treatments to correct them.

Allergic reaction. If you’ve had an allergic reaction to Kisqali or any of its ingredients, your doctor will likely not prescribe Kisqali. Ask your doctor what other medications may be better options for you.

Alcohol use with Kisqali

There aren’t any known interactions between alcohol and Kisqali.

But keep in mind that drinking alcohol could worsen certain side effects of Kisqali. This includes digestive problems, such as:

If you drink alcohol, talk with your doctor about the amount, if any, that’s safe for you to drink while taking Kisqali.

Pregnancy and breastfeeding while taking Kisqali

Below is information about taking Kisqali during pregnancy or while breastfeeding.

Kisqali and pregnancy

You should not take Kisqali if you are pregnant or planning to become pregnant.

Animal trials have shown harm to offspring that were exposed to Kisqali during pregnancy. Animal trials do not always predict what happens with humans. But because of the way Kisqali works in the body, it may cause harm to a fetus if taken during pregnancy.

Because of this risk, your doctor will have you take a pregnancy test to make sure you’re not pregnant before starting Kisqali.

If you or your partner are able to become pregnant, talk with your doctor. They’ll discuss effective birth control options for you. Females* should continue to use birth control for at least 3 weeks after their last dose of Kisqali. The drug manufacturer hasn’t provided birth control recommendations for males* taking the drug.

If you become pregnant while taking Kisqali, tell your doctor right away.

If you’re pregnant or planning to become pregnant, talk with your doctor before starting Kisqali. They’ll likely recommend a different treatment for your breast cancer.

Kisqali and breastfeeding

It may not be safe to breastfeed while taking Kisqali. It’s not known if Kisqali passes into breast milk.

Because of possible risks to a breastfed child, you should avoid breastfeeding while taking Kisqali. And you should continue to avoid breastfeeding for at least 3 weeks after you stop taking the drug.

Before starting treatment with Kisqali, tell your doctor if you’re breastfeeding or planning to breastfeed. They can suggest other healthy ways to feed your child. Or they may prescribe a different medication for your condition.

* Sex and gender exist on spectrums. Use of the terms “male” and “female” in this article refers to sex assigned at birth.

Mild and serious side effects have been reported with Kisqali. Most of Kisqali’s side effects are mild and are expected to go away with time. But be sure to tell your doctor if you have any serious side effects, such as serious skin reactions, with Kisqali.

If you’d like to learn more about Kisqali, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.