Temozolomide is used to treat certain types of brain tumors. Temozolomide is in a class of medications called alkylating agents. It works by slowing or stopping the growth of cancer cells in your body.

Side Effects Of Temozolomide

Temozolomide may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • nausea
  • vomiting
  • diarrhea
  • constipation
  • loss of appetite
  • sores in the mouth and throat
  • headache
  • pale skin
  • lack of energy
  • loss of balance or coordination
  • fainting
  • dizziness
  • hair loss
  • insomnia
  • memory problems
  • changes in vision

Some side effects can be serious. If you experience any of these symptoms, stop taking temozolomide and call your doctor immediately or get emergency medical treatment:

  • unusual bleeding or bruising
  • red or black, tarry stools
  • pink, red, or dark brown urine
  • coughing up or vomiting blood or material that looks like coffee grounds
  • fever, sore throat, ongoing cough, and congestion, or other signs of infection
  • unusual tiredness or weakness
  • rash
  • unable to move one side of the body
  • shortness of breath
  • seizures
  • yellowing of the skin or eyes
  • pain in the upper right part of the stomach
  • decreased urination
  • Temozolomide may increase the risk that you will develop other cancers. Talk to your doctor about the risks of taking temozolomide.

Temozolomide may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Warnings & Precautions

Before taking temozolomide:

  • tell your doctor and pharmacist if you are allergic to temozolomide, dacarbazine (DTIC-Dome) any other medications, or any of the ingredients in temozolomide capsules. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: carbamazepine (Carbatrol, Epitol, Tegretol); co-trimoxazole (Bactrim, Septra); phenytoin (Dilantin, Phenytek); steroids such as dexamethasone (Decadron, Dexone), methylprednisolone (Medrol), and prednisone (Deltasone); and valproic acid (Stavzor, Depakene).
  • tell your doctor if you have or have ever had kidney or liver disease.
  • you should know that temozolomide may interfere with sperm production in men. However, you should not assume that you cannot get someone else pregnant. Tell your doctor if you are pregnant or plan to become pregnant, or if you plan to father a child. You or your partner should not become pregnant while you are taking temozolomide. Use a reliable method of birth control to prevent pregnancy. If you become pregnant while taking temozolomide, call your doctor. Temozolomide may harm the fetus.
  • tell your doctor if you are breast-feeding. You should not breastfeed while you are taking temozolomide.

Dosage Of Temozolomide

Temozolomide comes as a capsule to take by mouth. It is usually taken once a day in the evening at bedtime. Take temozolomide capsules on an empty stomach with a glass of water. Take temozolomide at around the same time every day. For some types of brain tumors, temozolomide is taken daily for 42–49 days. Then, after a 28-day break, it may be taken once a day for 5 days in a row, followed by a 23-day break before repeating the next dosage cycle. For the treatment of other types of brain tumors, temozolomide is taken once a day for 5 days in a row, followed by a 23-day break before repeating the next dosage cycle. Your doctor will decide how many times you should repeat the treatment cycles. The length of treatment depends on how well your body responds to it and the type of cancer that you have. Take temozolomide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your full dose may contain more than one type and color of capsules and may be contained in more than one prescription bottle. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand.

Temozolomide capsules come in several different strengths. Your doctor may want you to take a combination of capsules to make up your full dose. Be sure that you know what each type of capsule looks like and how many you are to take of each. Ask your doctor or pharmacist if you have any questions.

If any of the capsules are broken or leaking, do not touch them with your bare hands, and be careful not to breathe in the powder from the capsules. You should wear rubber or latex gloves when you handle broken or opened capsules so that your skin does not come into contact with the powder. If the capsule contents do touch your skin, wash the area well with water right away.

Swallow the capsules whole; do not empty, chew, or crush them.

You may vomit after you take the medication. If this happens, let your doctor know right away. Do not take another dose of temozolomide on the same day.

Your doctor may need to delay your treatment or adjust your dose of temozolomide depending on your response to treatment and any side effects that you experience. Talk to your doctor about how you are feeling during your treatment. Do not stop taking temozolomide without talking to your doctor.

Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient.


Keep all appointments with your doctor and the laboratory. Your doctor will order laboratory tests before, during, and after your treatment to check your body’s response to temozolomide and to see if your blood cells are affected by this drug.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.