Pembrolizumab (Intravenous)

As a form of immunotherapy, Pembrolizumab targets a protein called PD-1 which triggers T-cells to find and destroy cancer cells.


Pembrolizumab is an immunotherapy medicine which helps to shrink tumors. It can also help patients with advanced melanoma to live longer. It is known as a checkpoint inhibitor, a type of medicine which helps to make cancer cells become more vulnerable to attack by the body's own immune system. It achieves this by promoting the tumor-destroying effects of T cells (white blood cells which the body uses to fight against disease and infection).

This medicine functions by blocking the activity of a molecule known as PD-1' a protein which stops T cells from recognizing or attacking inflamed tissues and/or cancer cells. Because Pembrolizumab blocks PD-1, it increases the ability of the immune system to attack tumors and melanomas, effectively allowing T cells to invade cancerous growths anywhere within the body.

Pembrolizumab was approved by the US Food & Drug Administration in 2014 to treat patients in the advanced stages of melanoma. It is particularly useful in treating stage three melanomas that are unable to be completely removed via surgical means, or stage four metastatic melanomas which have spread to organs or other body parts.

Many experts agree that anti-PD-1 therapies are effective first-line treatments for patients who have advanced melanoma.

Type Of Medicine

  • Immunotherapy

Conditions Treated

  • Cancer

Side Effects

Along with its desired effects, Pembrolizumab can also cause some unwanted side effects in certain patients. The most commonly reported side effects associated with this medication include the following:

  • Body aches or pains
  • Chills
  • Swelling or bloating of the hands, legs, arms face or feet
  • Constipation
  • Depression
  • Coughing
  • Difficulty breathing
  • Difficulty moving
  • Dry hair and skin
  • Congestion of the ears
  • Feeling cold
  • Headaches
  • Hair loss
  • Husky voice or hoarseness
  • Voice loss
  • Muscular cramps, stiffness and pain
  • Pale skin
  • Weight gain
  • Stuffy or runny nose
  • Slow heartbeat
  • Sore throat
  • Sneezing
  • Unusual bruising or bleeding
  • Unusual weakness or tiredness
  • Tingling in the hands or feet
  • Unusual weight loss or weight gain

As the patient continues to undergo treatment with Pembrolizumab as prescribed, the previously mentioned side effects should begin to lessen. If symptoms persist over time or appear to get worse, the patient should follow this up with their doctor as soon as possible. In some instances, a doctor or pharmacist may be able to recommend over the counter treatments to alleviate side effects which cause minor discomfort.

Most patients will only experience very minimal side effects while using this medication, if they experience any at all. The drug is intended to facilitate the destruction of dangerous cancer cells, and most doctors agree that the benefits of treating melanomas far outweigh the risk of experiencing mild side effects.

Other side effects, which are experienced rarely (albeit often enough to warrant mentioning) include the following:

  • Chest pain
  • Nervousness
  • General feeling of discomfort or illness
  • Increased sensitivity to heat
  • Stomach cramps
  • Tenderness
  • Sweating
  • Difficulty sleeping
  • Bloody or watery diarrhea
  • Thickening of the bronchial secretions
  • Bleeding gums
  • Nausea/vomiting
  • Nosebleeds
  • Red or swollen skin
  • Seizures
  • Light-colored stools
  • Blurred vision or other vision changes
  • Cracks in the skin
  • Darkened urine
  • Indigestion
  • Pain in the eyes
  • Pale skin
  • Decreased appetite
  • Dizziness

Because Pembrolizumab use can affect coordination and cause dizziness or vision changes, patients are advised against driving or operating heavy machinery until it has been observed that these particular side effects do not occur. This is to ensure the safety of both the patient and other road users.

Pembrolizumab can also affect the psychology of the patient, causing feelings of depression. Caution should therefore be taken when prescribing this medication to patients with a history of mental illness, such as schizophrenia, depression or bipolar disorder.

Not all side effects may have been documented. Patients who experience undocumented side effects are advised to contact their doctor as soon as possible and to report their findings to the FDA if they are inclined to do so.


Like all medicines, it is important to take Pembrolizumab only as it has been prescribed by a doctor. This means that patients should avoid taking any more of the drug than they have been advised to, both in terms of frequency and dose size. In addition to this, the patient should be prepared to stop taking this medication on the instruction of their doctor, even if they still have a supply of it remaining.

Usual dose for metastatic melanoma:

  • The patient should receive 200mg of Pembrolizumab intravenously over a half-hour period every three weeks, until the disease has sufficiently been defeated or unacceptable levels of toxicity occur.

The usual dose for non-small cell lung cancer, head and neck cancer, Hodgkin's disease, urothelial carcinoma, colorectal cancer, and/or solid tumors:

  • The patient should receive 200mg of Pembrolizumab intravenously over a half-hour period, every three weeks. The maximum period for this treatment without disease progression is 24 months, at which point an alternative therapy should be substituted for Pembrolizumab.

While the manufacturers of Pembrolizumab provide general dose instructions, it should be reiterated that these are merely guidelines which can be altered by the prescribing doctor. When determining the dose size, a doctor will take into account the age, height, weight, and condition of the patient, among other factors.

There is no recommended Pembrolizumab dose size for children. Instead, the manufacturer of this medicine leaves dosage terms at the discretion of the prescribing doctor.

Although it is unlikely given that patients will generally receive treatment with Pembrolizumab in a clinical setting, the manufacturer advises against taking double doses. If a patient misses a dose, they should simply arrange for the missed dose to be administered as soon as possible.

If the patient experiences any signs of an overdose (extremely fast or slow heartbeat, difficulty breathing, severe aches and pains, seizures and/or unconsciousness) they may require urgent medical attention.


All drugs have the potential to interact with other medications or chemicals within the human body. These interactions can change the effects of one or more of the associated drugs. In some cases, interactions can cause one or more drugs to become ineffective in treating the condition they were prescribed for. In other cases, interactions have been known to cause dangerous or even fatal reactions in patients. Because of these risks, it is important for patients to keep a full, detailed list of all medicines they are currently taking' and this extends to vitamins, herbal supplements, complementary medicines and over the counter remedies as well as prescribed drugs.

There are currently no documented negative drug interactions for Pembrolizumab. However, this does not mean that no interactions exist. Patients who think they may have experienced a negative drug interaction with Pembrolizumab are advised to consult their doctor or pharmacist, and to impart their findings to the FDA.


Pembrolizumab can potentially affect the way the immune system works. This can cause side effects which could lead to serious medical problems. Some patients may require other medicines to treat the side effects of Pembrolizumab, which in turn could result in cancer treatments being delayed while the side effects are alleviated. All patients undergoing treatment with Pembrolizumab should receive regular medical tests to help doctors and healthcare providers determine whether it is safe for them to continue using Pembrolizumab.

Before beginning treatment with Pembrolizumab, patients should inform their doctor or healthcare provider if they have ever experienced the following:

  • Liver disease
  • Kidney disease
  • Any thyroid disorder
  • Diabetes
  • Autoimmune disorders such as Crohn's disease, ulcerative colitis or lupus
  • Receiving an organ transplant
  • Lung disease
  • Any breathing disorder

Pregnant women are advised against taking Pembrolizumab. This is because treatment with this medication could harm unborn babies. Patients who become pregnant during the course of treatment with Pembrolizumab are advised to inform their doctor or healthcare provider immediately. Patients are advised to use effective birth control for at least four months after receiving an intravenous dose of Pembrolizumab.

It is currently unknown whether Pembrolizumab is excreted into breast milk. The advice of doctors is to avoid breast feeding while undergoing treatment with this medicine, and for at least four months after receiving the final dose of Pembrolizumab.

Pembrolizumab can pass into bodily fluids such as feces, urine or vomit. Patients are advised against allowing body fluids to come into contact with hands or other surfaces for at least 48 hours after receiving a dose of this medication. Caregivers should wear protective rubber gloves when cleaning up the patient's body fluids or handling any contaminated laundry. Hands should be washed before and after gloves are removed, and soiled linens/clothing should be washed separately from other laundry.

Patients who experience signs of an allergic reaction, including difficulty breathing, swelling of the face/lips/tongue/throat, and/or an occurrence of hives, are advised to seek immediate emergency medical help.

Because patients require ongoing monitoring while receiving therapy with Pembrolizumab, they are advised not to miss any follow-up appointments with their doctor.


Because Pembrolizumab is typically administered in a clinical environment (such as a hospital or doctor's surgery), the patient's healthcare provider will generally be responsible for the storage and maintenance of Pembrolizumab and any associated IV equipment such as drips or tubing.

Pembrolizumab should be stored at room temperature. Reconstituted and diluted solutions can be refrigerated, and should be kept for no longer than 6 hours after reconstitution at room temperature, or no longer than 24 hours if kept refrigerated (at a temperature between 2C and 8C.

In a clinical setting, the patient's healthcare provider will be responsible for the storage and disposal of unwanted, unused or expired Pembrolizumab, and should do so in accordance with state law and FDA guidelines.


While Pembrolizumab is an incredibly beneficial treatment, it can also pose a risk to patients who fail to communicate effectively with their physicians. As an immunotherapy, it helps the body's immunes system to fight cancer cells, encouraging T cells to completely envelop melanomas and tumors. However, it can also have many other negative effects on the immune system, including the causation of severe aches and pains which can become debilitating and put the patient at risk of ending up in a perilous situation.

For these reasons, it is imperative that the patient informs his or her doctor about their entire medical history, in order to rule out any potential interactions or avoidable side effects.

When taken correctly, Pembrolizumab can help the body to defeat cancers which would otherwise be inoperable or untreatable. To achieve this, doctor and patient must work together to determine the most effective dose and frequency of treatment.