Keytruda is a prescription medication used for the treatment of several types of cancer. It works by blocking a protein called PD-1 on T-cells, which allows the immune system to recognize and attack cancer cells [1]. However, like all medications, Keytruda has potential side effects that can range from mild to severe.

According to the official Keytruda website, some of the most common side effects of the medication include fatigue, cough, nausea, rash, decreased appetite, constipation, joint pain, and diarrhea [2]. These side effects are usually mild and can be managed with medication or other interventions.

However, there are also more serious Keytruda side effects that can occur. One potential side effect is an immune system reaction known as immune-mediated pneumonitis, which can cause shortness of breath, chest pain, and coughing. This side effect can be life-threatening and requires immediate medical attention [2].

Another potential serious side effect of Keytruda is colitis, which is inflammation of the colon. Symptoms of colitis include diarrhea, abdominal pain, and blood in the stool. Like immune-mediated pneumonitis, colitis can be life-threatening and requires immediate medical attention [3].

In addition to these side effects, Keytruda can also cause other immune system reactions such as hepatitis, hypothyroidism, and nephritis [3]. It is important to note that not all patients will experience these side effects, and the severity of the side effects can vary from person to person.

In conclusion, while Keytruda can be an effective treatment for certain types of cancer, it is important to be aware of the potential side effects. Some of the most serious side effects include immune-mediated pneumonitis and colitis, which can be life-threatening. Patients should speak with their healthcare provider about the potential risks and benefits of Keytruda treatment, and report any side effects immediately.

Sources:
[1] https://www.drugpatentwatch.com/p/biologics/tradename/KEYTRUDA
[2] https://www.keytruda.com/side-effects/
[3] https://www.cancer.net/navigating-cancer-care/how-cancer-treated/immunotherapy-and-vaccines/side-effects-immunotherapy