Side Effects From Steroids & Premedications

A lot of chemotherapy appointments start with drugs that are not chemotherapy. The most common is a steroid, usually dexamethasone, often paired with an antihistamine. These are premedications. They are given to prevent or reduce nausea and vomiting caused by chemotherapy, and to prevent allergic reactions caused by some chemotherapy drugs such as docetaxel and paclitaxel.

Because they are described as helpers, people are often not warned that they can be strongly felt in their own right. Knowing what is expected takes a lot of the alarm out of it.

For nausea, dexamethasone is taken about 30 minutes before chemotherapy, and it may be continued every 12 hours after chemotherapy for a period your team specifies. For preventing allergic reactions, it is taken before specific drugs like docetaxel or paclitaxel. Take it with food and a glass of water or milk. If you miss a dose, or vomit within one hour of taking dexamethasone, take it as soon as you can.

Take it exactly as prescribed. Do not skip doses or take more than directed.

Difficulty falling asleep on treatment days is a listed effect of dexamethasone given as a premedication. Insomnia and restlessness are also listed among dexamethasone's side effects in general. So the familiar pattern of lying wide awake on the night of chemo is a known drug effect, not a personal failing. Sleep is expected to return to normal when you stop taking dexamethasone.

Discuss sleep concerns with your doctor rather than changing the steroid dose yourself. Our page on sleep problems during cancer treatment covers what actually helps.

Depression and anxiety are both listed side effects of dexamethasone. The general instruction is to tell your doctor if any of these symptoms are severe or do not go away.

For dexamethasone used as a premedication, mood changes carry a stronger instruction: see your doctor as soon as possible, during office hours, if you have mood changes. That is not an emergency-room instruction, but it is not a wait-until-next-cycle one either.

This is the effect people are least often warned about. The consumer drug information says: "If you have diabetes, dexamethasone may increase your blood sugar level. If you monitor your blood sugar (glucose) at home, test your blood or urine more frequently than usual. Call your doctor if your blood sugar is high or if sugar is present in your urine; your dose of diabetes medication and your diet may need to be changed."

Dexamethasone increases the risk of stomach irritation, which is why it is taken with food or milk. Heartburn and an increased risk of stomach problems, including bleeding ulcers, are listed for premedication use. Acetaminophen can be used for minor pain; ask your doctor about the timing of any antacid.

Appetite and weight changes are widely described by people on steroids, but the consumer drug information we used here does not list increased appetite or weight gain among dexamethasone's side effects. What it does list, on the urgent side, is swelling of the face, lower legs, or ankles. If your appetite or weight changes noticeably, raise it with your team rather than assuming it is unavoidable.

Steroids lower the body's immune response, so you are more likely to get sick. Report any injuries or signs of infection — fever, sore throat, pain during urination, and muscle aches — that occur during treatment. Avoid contact with anyone who has chicken pox or measles.

Do not stop taking dexamethasone without talking to your doctor. Stopping suddenly can cause loss of appetite, upset stomach, vomiting, drowsiness, confusion, headache, fever, joint and muscle pain, peeling skin, and weight loss. If the steroid is to be stopped, your doctor will likely decrease the dose gradually.

Diphenhydramine is often given before chemotherapy to help prevent allergic reactions. Drowsiness, dizziness, dry mouth, nose and throat, and muscle weakness are common effects. The instruction is plain: "Do not drive a car or operate machinery until you know how this medication affects you." Alcohol adds to the drowsiness, so avoid alcoholic drinks while taking it. Arrange a ride home from infusion days. In older adults, diphenhydramine should not be used except to manage serious allergic reactions. Vision problems or difficult or painful urination should prompt an immediate call to your doctor.

Call your doctor immediately if you have skin rash; swollen face, lower legs, or ankles; vision problems; a cold or infection that lasts a long time; muscle weakness; or black or tarry stool.

Call your doctor if your blood sugar is high or if sugar is present in your urine. See your doctor as soon as possible during office hours if you have mood changes. And tell your doctor if upset stomach, vomiting, headache, dizziness, insomnia, restlessness, depression, anxiety, acne, easy bruising, or menstrual changes are severe or do not go away.

If your own team has given you a different rule about when to call between visits or after hours, follow their rule.

Steroid Insomnia, Anxiety, and Mood Changes, Sleep Problems During Cancer Treatment, Side Effects Overview, Questions About Treatment Side Effects, and Fever and Infection Concerns During Cancer Treatment.

• MedlinePlus, U.S. National Library of Medicine, Dexamethasone
• MedlinePlus, U.S. National Library of Medicine, Diphenhydramine
• BC Cancer, For the Patient: Dexamethasone (for premedication)