SIDE EFFECTS: Nausea, vomiting, upset stomach, loss of appetite, weight loss, constipation, tiredness/weakness, headache, or change in how food tastes may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. Diarrhea is a common side effect that can cause a serious loss of body water (dehydration). Tell your doctor right away if you have loose stools, and ask if you should take anti-diarrheal medication (such as loperamide). Drink plenty of fluids to reduce the risk of dehydration. Contact your doctor promptly if you notice any symptoms of dehydration, such as unusual decreased urination, unusual dry mouth/thirst, fast heartbeat, or dizziness/lightheadedness. Temporary hair loss may occur. Normal hair growth should return after treatment has ended. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: unusual tiredness, easy bruising or bleeding (such as nose/gum bleeds, pink/dark urine), signs of liver damage (such as nausea/vomiting that doesn't stop, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine). This medication may lower your ability to fight infections. This may make you more likely to get a serious (rarely fatal) infection or make any infection you have worse. Tell your doctor right away if you have any signs of infection (such as sore throat that doesn't go away, fever, chills, cough). This medication may rarely cause blood clots (such as pulmonary embolism, stroke, heart attack, deep vein thrombosis). You may be at increased risk for blood clots if you are severely dehydrated, or have a history of blood clots, or if you are immobile (such as on very long plane flights or being bedridden). If you use estrogen-containing products, these may also increase your risk. Before using this medication, if you have any of these conditions report them to your doctor or pharmacist. Get medical help right away if any of these side effects occur: shortness of breath/rapid breathing, chest/jaw/left arm pain, unusual sweating, confusion, sudden dizziness/fainting, pain/swelling/warmth in the groin/calf, sudden severe headaches, trouble speaking, weakness on one side of the body, sudden vision changes. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking abemaciclib, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, bleeding/clotting problems (such as bleeding from intestinal/stomach ulcers). Abemaciclib can make you more likely to get infections or may worsen any current infections. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details. Do not have immunizations/vaccinations without the consent of your doctor. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose). This drug may make you dizzy. Alcohol or marijuana can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana. Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets. Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using abemaciclib. Abemaciclib may harm an unborn baby. Ask about reliable forms of birth control while using this medication and for at least 3 weeks after stopping treatment. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication. It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug and for at least 3 weeks after stopping treatment is not recommended. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Other medications can affect the removal of abemaciclib from your body, which may affect how abemaciclib works. Examples include azole antifungals (such as ketoconazole, itraconazole, voriconazole), macrolide antibiotics (such as clarithromycin), HIV protease inhibitors (such as ritonavir, atazanavir, nelfinavir, saquinavir, indinavir), rifamycins (such as rifampin, rifabutin), drugs to treat seizures (such as phenytoin, carbamazepine, phenobarbital), nefazodone, St. John's wort, telithromycin, among others.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: seizures, extreme dizziness, headache that is extreme or doesn't go away, vomiting blood.