What are the side effects of Pembrolizumab?

Pembrolizumab, marketed under the brand name Keytruda, is an immunotherapy drug used to treat various types of cancers, including melanoma, non-small cell lung cancer, head and neck squamous cell carcinoma, and classical Hodgkin lymphoma, among others. By targeting the PD-1/PD-L1 pathway, Pembrolizumab helps the immune system recognize and attack cancer cells more effectively. However, like all medications, it can cause side effects, some of which can be serious. Understanding these potential side effects is critical for patients and healthcare providers to manage them effectively.

Common side effects of Pembrolizumab include fatigue, rash, itching, diarrhea, and loss of appetite. These side effects are usually mild to moderate and often manageably resolve on their own or with supportive care. Fatigue is particularly common and may impact daily activities, but it typically improves with rest and a balanced diet. Skin-related side effects like rash and itching can often be managed with topical treatments and antihistamines.

More significant side effects can occur and may require medical intervention. One of the serious risks associated with Pembrolizumab is immune-related adverse effects. Since Pembrolizumab works by stimulating the immune system, it can sometimes cause the immune system to attack healthy cells and tissues, leading to conditions such as pneumonitis (inflammation of the lungs), colitis (inflammation of the colon), hepatitis (inflammation of the liver), nephritis (inflammation of the kidneys), and endocrinopathies (disorders of the endocrine glands). These conditions can be life-threatening if not promptly recognized and treated. Symptoms of these immune-related side effects might include shortness of breath, severe abdominal pain, jaundice, and changes in urination or hormonal imbalances.

Another notable side effect is infusion-related reactions. These can occur during or shortly after the Pembrolizumab infusion and might include symptoms like fever, chills, nausea, headache, and changes in blood pressure. If an infusion reaction occurs, the healthcare team might slow down or pause the infusion and administer medications to manage the symptoms.

Pembrolizumab can also affect blood cell counts, leading to conditions like anemia (low red blood cells), leukopenia (low white blood cells), and thrombocytopenia (low platelets). These conditions might cause fatigue, increased risk of infections, and easy bruising or bleeding, respectively. Regular blood tests are typically conducted to monitor these parameters and guide treatment adjustments if necessary.

It is crucial for patients receiving Pembrolizumab to maintain open communication with their healthcare providers. Any new or worsening symptoms should be reported immediately, as early intervention can often prevent more severe complications. Healthcare providers will also conduct regular monitoring, including blood tests and imaging studies, to detect and manage side effects promptly.

In conclusion, while Pembrolizumab offers significant benefits in treating certain cancers by harnessing the power of the immune system, it is associated with a range of potential side effects. Patients and healthcare providers must work closely together to monitor and manage these side effects, ensuring the best possible outcomes from this innovative cancer treatment.