Common targeted therapy side effects and how to manage them

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science

This page was updated on April 1, 2022.

Targeted therapy fights specific parts of cancer cells, such as genes or proteins, which are the building blocks that help cancers grow.

Some types of targeted therapies include:

  • Hormone therapies
  • Signal transduction inhibitors
  • Gene expression modulators
  • Immunotherapies

If your cancer care team has recommended targeted therapy, you may be wondering what it’ll do in your body and how your body may handle this new medication. Side effects are possible and vary from drug to drug and person to person. Some side effects are mild, while others may be severe. Some resolve quickly, while others last longer.

Your experience is your own—you may have just a few minor side effects or more severe, longer-lasting ones during or after treatment that may require more management strategies.

Having frequent, consistent and open dialogue with your care team about side effects before, during and after treatment is critical for receiving the appropriate recommendations to help you manage.

Why does targeted therapy cause side effects?

Targeted therapy uses drugs to interrupt what fuels cancer cells. But sometimes these drugs also affect healthy cells, which may share a similar protein or other target. While targeted therapy is designed to be less toxic than traditional cancer treatments (such as chemotherapy), you still may experience a variety of side effects, depending on the type of treatment and dosage.

How long will side effects from targeted therapy last?

Side effects of targeted therapy generally develop slowly after your first treatment and may continue for weeks. You may also experience continuing side effects weeks or months post-treatment, which may take a little longer to completely fade. Since targeted therapies are fairly new, it’s not always clear how long side effects may last.

What are the side effects of targeted therapy?

Knowing as much as you can about the various side effects of targeted therapy and what to expect may help you feel more in control and at ease during treatment. Below, find a few main overarching side effects of targeted therapy.

Fatigue: You may experience tiredness or utter exhaustion during cancer treatment, and cancer fatigue feels very different from the fatigue you may have from your normal routine. It’s important to remember the level of fatigue differs between each person, so no two patients have the same experience.

Some ways to manage fatigue include:

  • Take time for both relaxation and being active. Work on finding an even balance between time to relax and rest vs. time for light movement and activity (such as a walk around the neighborhood or working in the garden).
  • Follow a healthy diet. Make water your drink of choice, and make sure your diet is a mix of protein, carbohydrates, fat, vitamins and minerals to help keep your energy levels up.
  • Meet with a mental health expert. Speak with a counselor or psychologist to help you cope with the stress from symptoms and the difficult thoughts and emotions you may be experiencing during cancer treatments.

Skin irritation: Targeted therapy may cause dry skin, a rash or nail problems. You may also experience sensitivity to light, itching or hand-foot syndrome.

Some ways to manage skin irritation include:

  • Avoid the sun. Sunshine may cause further irritation, so try to cover your skin and use a sunscreen with a minimum of SPF 30.
  • Use dressings. Your health-care provider may recommend specific creams or ointments for skin swelling or dryness. In more severe cases, your doctor may give you a prescription for antihistamines or steroids.
  • Cleanse your skin correctly. Using warm (not hot) water and an unscented soap to rinse your skin are ideal for cleaning. Instead of rubbing your skin with a towel, it’s better to pat it dry. Showering in lukewarm water and avoiding long showers may also help.
  • Add moisture. Lather the irritated areas of your skin with cream or thicker lotion to add moisture to the affected skin within five minutes of showering or bathing.

Fever and chills: Your body temperature may spike during or after targeted therapy treatment.

Some ways to manage fever and chills include:

  • Cool down. Run a cloth under cold water, then place it on top of your forehead.
  • Prevent excess heat. Avoid wrapping your body in blankets, as it may raise your temperature even higher.
  • Speak with an expert. If fever and chills continue, reach out to your doctor and ask about prescription medications that may help.

Nausea and vomiting: Targeted therapy may make you vomit, or you may feel queasy or lightheaded.

Some ways to manage nausea and vomiting include:

  • Change your diet and the size of your meals. Eating bland foods such as toast or crackers and drinking clear liquids may help. Instead of eating larger meals less often, sample smaller meals more frequently.
  • Try to relax. Focus on mindful exercises, which may include practices such as meditation, acupressure or acupuncture.
  • Speak with an expert. If nausea doesn’t go away, ask your doctor about medications that may help prevent and treat the issue.

Hair loss (alopecia): Some targeted treatments may cause your hair to thin or fall out. You may lose hair not only on your head (including eyebrows and eyelashes), but also on your arms and legs and in your pubic area.

Some ways to manage hair loss include:

  • Try cooling caps. Worn before, during and after treatments, cooling caps may reduce risk of hair loss, but some patients find them to be uncomfortable and cause headaches.
  • Cover your head. Some people choose to get wigs or wear scarves. A wig may be covered by your insurance provider, so be sure to ask your care team. Tender Loving Care, a program run by the American Cancer Society, helps provide wigs, hats and scarves as well.
  • Take action beforehand. You may want to cut your hair short or shave your head before fallout begins.
  • Show your hair some TLC. If you’re extra kind to your head, you may not lose as much hair. This means don’t brush your hair too often or pull too hard when you do, and avoid using blow-dryers and curling irons. You’ll also want to avoid perms and hair dyes—it’s especially important to avoid these when your hair starts to come back.

Diarrhea: During targeted treatment, specifically to the abdomen or areas around the abdomen, you may experience diarrhea, or loose stools, as a side effect.

Some ways to manage diarrhea include:

  • Focus on hydration. You lose fluids when you have diarrhea, so drinking plenty of water and electrolytes may help to deter dehydration and replenish what you lost. If diarrhea continues, it’s possible your doctor may prescribe medications to help.
  • Eat smaller meals. Aim for six to eight mini meals eaten throughout the day. This helps so that your body doesn’t have to work as hard to digest larger meals eaten less frequently. Aim to fill your plate with foods high in minerals such as potassium and sodium—you lose both when you experience diarrhea.

High blood pressure: Some targeted therapy cancer medications, such as angiogenesis inhibitors, may block new blood vessel growth, which may elevate your blood pressure.

Natural ways to manage high blood pressure include:

  • Exercise regularly.
  • Eat a balanced diet.
  • Reduce sodium.
  • Limit alcohol and caffeine.
  • Quit smoking.

Considering that many of these remedies may also be affected by your targeted therapy, if you are experiencing high blood pressure, speak with your physician to help determine the most appropriate path to management. This may include medication. It may also be helpful to use a blood pressure monitor to track your levels on a regular basis.

Slow wound healing: These drugs may interfere with and delay wound healing. Not only can this affect small wounds, such as cuts, but it may also lead to holes in the linings of the stomach and intestine. Contact your doctor right away if you’re experiencing abdominal pain or intense vomiting.

Bleeding or clotting: While more uncommon, you may experience bruising, bleeding or clotting during or after targeted therapy. Some types of drugs for this therapy may interfere with new blood vessel growth. Other therapies may deplete blood cells, which are used to clot the blood to stop bleeding. This side effect is harder to identify and manage, but if your vomit is black or looks like coffee grounds, contact your doctor right away.

Autoimmune reactions: Many cancer drugs cause a shock to your immune system, making your body more susceptible to illness and autoimmune reactions, including attacks to healthy parts of your body.

Swelling: Depending on your treatment, some targeted therapies may cause swelling, including around the eyes or in the feet, legs or hands.

Some ways to ease swelling include:

  • Ice the inflamed area.
  • Get rest.
  • Elevate the swollen area.
  • Ask your doctor about taking a diuretic or ibuprofen.

Heart damage: Many targeted therapy drugs affect blood vessel growth and may also damage the heart, particularly if they’re paired with certain chemotherapy drugs. If you’re experiencing chest pain, increased coughing, trouble breathing, rapid weight gain, dizziness or swelling in the ankles or legs, you should consult with your doctor.

When to seek medical attention for side effects

Most side effects can and should be treated quickly, so having early conversations with your cancer care team about all types of side effects related to your particular type of targeted therapy is important.

If you experience any noticeable or irregular changes in physical appearance or your physiological state after being treated with targeted therapy, you should contact your health-care provider immediately.

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