Important Safety Information

KEYTRUDA® (pembrolizumab) is a medicine that may treat certain cancers by working with your immune system. KEYTRUDA can cause your immune system to attack normal organs and tissues in any area of your body and can affect the way they work. These problems can sometimes become serious or life-threatening and can lead to death.

Call or see your doctor right away if you develop any symptoms of the following problems or these symptoms get worse:

Lung problems (pneumonitis). Symptoms of pneumonitis may include shortness of breath, chest pain, or new or worse cough.

Intestinal problems (colitis) that can lead to tears or holes in your intestine. Signs and symptoms of colitis may include diarrhea or more bowel movements than usual; stools that are black, tarry, sticky, or have blood or mucus; or severe stomach-area (abdomen) pain or tenderness.

Liver problems (hepatitis). Signs and symptoms of hepatitis may include yellowing of your skin or the whites of your eyes, nausea or vomiting, pain on the right side of your stomach area (abdomen), dark urine, feeling less hungry than usual, or bleeding or bruising more easily than normal.

Hormone gland problems (especially the thyroid, pituitary, adrenal glands, and pancreas). Signs and symptoms that your hormone glands are not working properly may include rapid heartbeat, weight loss or weight gain, increased sweating, feeling more hungry or thirsty, urinating more often than usual, hair loss, feeling cold, constipation, your voice gets deeper, muscle aches, dizziness or fainting, or headaches that will not go away or unusual headache.

Kidney problems, including nephritis and kidney failure. Signs of kidney problems may include change in the amount or color of your urine.

Skin problems. Signs of skin problems may include rash, itching, blisters, peeling or skin sores, or painful sores or ulcers in your mouth or in your nose, throat, or genital area.

Problems in other organs. Signs of these problems may include changes in eyesight, severe or persistent muscle or joint pains, severe muscle weakness, low red blood cells (anemia), shortness of breath, irregular heartbeat, feeling tired, or chest pain (myocarditis).

Infusion (IV) reactions that can sometimes be severe and life-threatening. Signs and symptoms of infusion reactions may include chills or shaking, shortness of breath or wheezing, itching or rash, flushing, dizziness, fever, or feeling like passing out.

Rejection of a transplanted organ. People who have had an organ transplant may have an increased risk of organ transplant rejection if they are treated with KEYTRUDA.

Getting medical treatment right away may help keep these problems from becoming more serious. Your doctor will check you for these problems during treatment with KEYTRUDA. Your doctor may treat you with corticosteroid or hormone replacement medicines. Your doctor may also need to delay or completely stop treatment with KEYTRUDA if you have severe side effects.

Before you receive KEYTRUDA, tell your doctor if you have immune system problems such as Crohn’s disease, ulcerative colitis, or lupus; have had an organ transplant; have lung or breathing problems; have liver problems; or have any other medical problems.

If you are pregnant or plan to become pregnant, tell your doctor. KEYTRUDA can harm your unborn baby. Females who are able to become pregnant should use an effective method of birth control during treatment and for at least 4 months after the final dose of KEYTRUDA. Tell your doctor right away if you become pregnant during treatment with KEYTRUDA.

If you are breastfeeding or plan to breastfeed, tell your doctor. It is not known if KEYTRUDA passes into your breast milk. Do not breastfeed during treatment with KEYTRUDA and for 4 months after your final dose of KEYTRUDA.

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Common side effects of KEYTRUDA include feeling tired, itching, diarrhea, decreased appetite, rash, fever, cough, shortness of breath, pain in muscles, bones or joints, constipation, and nausea.

These are not all the possible side effects of KEYTRUDA. Tell your doctor if you have any side effect that bothers you or that does not go away. For more information, ask your doctor or pharmacist.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call
1-800-FDA-1088.

Please read the accompanying Medication Guide for KEYTRUDA and discuss it with your doctor. The physician Prescribing Information also is available.

Copyright © 2017 Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc. All rights reserved.

ONCO-1210548-0004 09/17


Medication Guide

Prescribing Information