Temozolomide Side Effects

Medically reviewed by Drugs.com. Last updated on Jun 29, 2025.

Applies to temozolomide: intravenous powder for solution.

Other dosage forms:

• oral capsule

Precautions

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

This medicine may cause birth defects if either partner is using it during conception or pregnancy. If you are a woman who can get pregnant, your doctor may do tests to make sure you are not pregnant before receiving this medicine. Use an effective form of birth control during treatment and for at least 6 months after your last dose. Males with female partners who are able to become pregnant should use an effective form of birth control during treatment and for 3 months after the last dose. If you think you have become pregnant, tell your doctor right away.

Temozolomide injection can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection (eg, pneumonia). It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

• If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you have fever or chills, cough or hoarseness, lower back or side pain, painful or difficult urination, shortness of breath, or unusual bleeding or bruising.
• Check with your doctor immediately if you notice any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, or pinpoint red spots on your skin.
• Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
• Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
• Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
• Avoid contact sports or other situations where bruising or injury could occur.

Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.

This medicine may cause serious lung or breathing problems (eg, pneumonia). Check with your doctor right away if you have chest pain or tightness, cough, fever or chills, sneezing, sore throat, or trouble breathing.

This medicine may increase risk of blood problems and secondary cancer (eg, myeloid leukemia). Check with your doctor right away if you have chest pain, chills, cough or hoarseness, fever, lower back or side pain, painful or difficult urination, sores, ulcers, or white spots on the lips or in the mouth, swollen glands, trouble breathing, unusual bleeding or bruising, or unusual tiredness or weakness.

Male patients should not donate semen during treatment and for at least 3 months after the final dose of this medicine.

If you plan to have children, talk with your doctor before using this medicine. Some men using this medicine have become infertile (unable to have children).

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Serious side effects of temozolomide

Along with its needed effects, temozolomide may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking temozolomide:

Other side effects of temozolomide

Some side effects of temozolomide may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

See also:

For healthcare professionals

Applies to temozolomide: intravenous powder for injection, oral capsule.

General adverse events

The most common side effects were alopecia, nausea, vomiting, anorexia, headache, and constipation.^[Ref]

Gastrointestinal

• Very common (10% or more): Constipation (Up to 33%), nausea (Up to 53%), vomiting (Up to 42%), diarrhea (16%)
• Common (1% to 10%): Abdominal pain, diarrhea, stomatitis, taste perversion, dysphagia, dyspepsia
• Uncommon (0.1% to 1%): Abdominal distension, fecal incontinence, gastrointestinal disorder, gastroenteritis, hemorrhoids^[Ref]

Nervous system

• Very common (10% or more): Headache (Up to 41%), convulsions (Up to 23%), hemiparesis (18%), abnormal coordination (11%)
• Common (1% to 10%): Dizziness, confusion, memory impairment, amnesia, paresthesia, somnolence, paresis, urinary incontinence, ataxia, abnormal gait, neuropathy, balance impairment, speech disorder, tremors, hemiparesis^[Ref]

Cardiovascular

• Very common (10% or more): Peripheral edema (11%)
• Uncommon (0.1% to 1%): Palpitation^[Ref]

Other

• Very common (10% or more): Fatigue (Up to 61%), asthenia (13%), fever (13%)
• Common (1% to 10%): Weakness, radiation injury, face edema, pain, hearing impairment
• Uncommon (0.1% to 1%): Otitis media, tinnitus, hyperacusis, earache, deafness, vertigo, impotence, vaginal hemorrhage, menorrhagia, amenorrhea, vaginitis, breast pain^[Ref]

Endocrine

• Common (1% to 10%): Adrenal hypercorticism^[Ref]

Respiratory

• Common (1% to 10%): Cough, dyspnea, upper respiratory tract infection, pharyngitis, sinusitis

Post-marketing surveillance: Interstitial pneumonitis, pneumonitis, alveolitis, pulmonary fibrosis^[Ref]

Dermatologic

• Very common (10% or more): Alopecia (55 to 69%), rash (13 to 19%)
• Common (1% to 10%): Dry skin, erythema, pruritus, petechiae
• Uncommon (0.1% to 1%): Photosensitivity reaction, abnormal pigmentation, sweating increased

Post-marketing surveillance: Toxic epidermal necrolysis, Stevens-Johnson syndrome^[Ref]

A case of diffuse erythematous skin rash that progressed to an extensive full body desquamative skin rash has been reported. Even though temozolomide was permanently discontinued, the patient continued to experience the rash on a long-term basis with periodic exacerbations.^[Ref]

Psychiatric

• Common (1% to 10%): Insomnia, anxiety, depression
• Uncommon (0.1% to 1%): Agitation, apathy, behavior disorder, hallucination, amnesia^[Ref]

Metabolic

• Very common (10% or more): Anorexia (19 to 27%)
• Common (1% to 10%): Weight increase, weight decrease, hyperglycemia
• Uncommon (0.1% to 1%): Hypokalemia^[Ref]

Musculoskeletal

• Common (1% to 10%): Arthralgia, back pain^[Ref]

Ocular

• Common (1% to 10%): Vision blurred, diplopia
• Uncommon (0.1% to 1%): Hemianopia, visual acuity reduced, vision disorder, visual field defect, eye pain, dry eyes^[Ref]

Immunologic

• Common (1% to 10%): Infection, Herpes simplex, wound infection, candidiasis oral
• Uncommon (0.1% to 1%): Herpes zoster, influenza-like symptoms

Post-marketing surveillance: Opportunistic infections including Pneumocystis pneumonia^[Ref]

Oncologic

Post-marketing surveillance: Secondary malignancies including myeloid leukemia^[Ref]

Hematologic

• Common (1% to 10%): Thrombocytopenia, hemorrhage, leukopenia, neutropenia, lymphopenia, febrile neutropenia, anemia

Post-marketing surveillance: Prolonged pancytopenia, myelodysplastic syndrome^[Ref]

Hepatic

• Common (1% to 10%): ALT increased
• Uncommon (0.1% to 1%): Hepatic enzymes increased, Gamma GT increased, AST increased

Post-marketing surveillance: Fatal and severe hepatotoxicity, elevation of liver enzymes, hyperbilirubinemia, cholestasis, hepatitis

Hypersensitivity

• Common (1% to 10%): Allergic reaction

Renal

• Common (1% to 10%): Urinary tract infection, micturition increased frequency
• Uncommon (0.1% to 1%): Dysuria

Frequently asked questions

• How long does chemo take? Sessions, cycles, and recovery time?

Further information

Temozolomide side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer