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At a glance
- Treatment
- Temozolomide; Temodal and generic brands
- Used in selected settings
- Glioma and selected neuroendocrine tumours
- How it is given
- Usually capsules, taken on an empty stomach as directed, often at least 1 hour before food. Swallow whole; do not open or crush them. Different strengths may be needed for one dose.
- Before you start
- Save your 24-hour oncology number and have a thermometer and written medicine calendar available.
What this treatment is and how it works
An alkylating chemotherapy medicine that damages cancer-cell DNA (the genetic instructions inside cells) and can reach tumours in the brain.
When it may be used
Temozolomide is used for selected gliomas, including treatment with and after radiotherapy for glioblastoma and treatment of some brain tumours that have returned or grown. It is also used with other medicines for selected advanced neuroendocrine tumours. Treatment aims to control the tumour and delay its growth or return; the expected benefit depends on the tumour type and complete treatment plan. Your team will explain the goal for you.
A listed use is not a claim that every brand is licensed for that use in every country. Your oncologist will explain why this treatment is appropriate for you.
Before treatment
Before starting, tell the team about previous cancer treatment, allergies, infection symptoms, heart, lung, kidney or liver disease, hearing or nerve problems, diabetes and all medicines you take. Discuss pregnancy, contraception and fertility. Ask for a written treatment calendar, supportive-medicine instructions and a 24-hour oncology contact number. Baseline blood tests usually include a full blood count and kidney and liver function; additional tests depend on the medicine and your health. Before chemotherapy that reaches the whole body, the team should check for current or past hepatitis B infection. If a test is positive, extra monitoring or antiviral treatment may be needed to prevent the virus becoming active again. The team will coordinate testing and treatment; do not delay urgent cancer treatment yourself.
How treatment is given and the schedule
Usually capsules, taken on an empty stomach as directed, often at least 1 hour before food. Swallow whole; do not open or crush them. Different strengths may be needed for one dose.
With radiotherapy for glioblastoma, it is commonly taken every day, including weekends, for about 6 weeks. After a break, a common schedule is 5 treatment days followed by 23 days off. Other brain-tumour protocols differ.
The dose is calculated for your treatment and health. Rest periods, delays or dose changes may be needed. Do not change doses or treatment dates yourself, except to follow specific instructions to stop a medicine and seek help for warning symptoms. The team will give you a revised plan when needed.
Tests and monitoring during treatment
Blood counts are checked closely. Liver tests are needed before treatment, during a prolonged daily course and after treatment cycles. Pneumocystis pneumonia prevention is required during the prolonged concurrent radiotherapy course and may continue if immune-cell counts remain low.
At each review, describe symptoms since the previous dose, including problems that have already settled. Blood tests can detect effects before you feel them. Your team may delay, reduce, omit or stop a medicine if results or symptoms make this necessary. The decision depends on the exact protocol; a normal result does not make new symptoms safe to ignore.
Side effects: what to expect
Frequency varies with the dose, schedule, cancer and other treatments. “Common or more frequent” is a practical grouping, not a single percentage for every patient. Some serious effects appear in more than one group because severity and frequency are different.
You are unlikely to have all of these effects. This is not an exhaustive list. Tell the team about any new or troublesome symptom, including one not mentioned here.
Common or more frequent side effects
| Possible effect | What you can do | When to contact the team |
|---|---|---|
| Feeling or being sick | Take preventive anti-sickness medicines at the prescribed times. Try small meals and frequent small drinks; avoid strong food smells if they worsen nausea. | Contact the team the same day if medicines are not controlling symptoms. Seek urgent advice if you cannot keep fluids down, feel faint or pass much less urine. |
| Constipation | Keep a bowel record. Gentle movement, usual fluids and a prescribed laxative can help. Ask before using suppositories or enemas when blood counts may be low. | Contact the team for worsening constipation. A swollen or painful abdomen, vomiting or inability to pass wind needs urgent assessment; do not simply add laxatives. |
| Reduced appetite or changes in eating | Try smaller, frequent meals with protein and energy-rich foods you tolerate. Ask for a dietitian if your weight or intake is falling. | Report ongoing weight loss or difficulty eating. Inability to drink or signs of dehydration needs same-day urgent advice. |
| Tiredness and reduced stamina | Balance rest with short periods of gentle activity. Prioritise tasks and accept help with shopping, meals or transport. Tell the team about poor sleep or pain. | Report fatigue that prevents basic activities or is worsening. Sudden breathlessness, chest pain, fainting or confusion needs urgent assessment. |
| Headache | Use only pain relief approved by your team and report new or persistent headaches. | A sudden severe headache, repeated vomiting, weakness, confusion, a seizure or a new vision problem needs urgent assessment. |
| Low blood counts | White cells fight infection, red cells carry oxygen and platelets help clotting. Treatment can lower one or more of these. Wash hands, avoid close contact with people who are unwell and keep blood-test appointments. | Call immediately for fever, shaking chills or feeling suddenly unwell. Report unusual bruising, bleeding, marked tiredness or increasing breathlessness. Do not wait for a blood-test result before seeking help. |
| Skin changes | Use gentle cleansers, a plain moisturiser, protective clothing and broad-spectrum sunscreen. Avoid applying new herbal or medicated products without advice. | Report a new or worsening rash. Blisters, peeling skin or sores involving the mouth or eyes need urgent medical assessment. |
Other reported side effects (frequency varies)
These effects may be common in some treatment settings, less common in others, or have no reliable frequency estimate. Their position here does not mean they are necessarily less frequent or less serious.
Hair loss, diarrhoea and liver-test changes may occur. Headache, weakness or seizures can also arise from the brain tumour and must be assessed rather than automatically attributed to the medicine.
Report these at review, or sooner if worsening. Use the urgent guidance for symptoms that affect breathing, drinking, urination, walking, consciousness or bleeding.
Important serious side effects, including rare effects
Serious does not always mean rare. Where reliable incidence is unavailable, no numerical frequency is assigned. The action to take matters even when the likelihood is uncertain.
Serious liver injury
Yellow eyes or skin, dark urine, severe upper abdominal pain, rapid abdominal swelling or unexplained weight gain needs urgent review. Some treatments can injure the small blood vessels in the liver.
Infections during prolonged immune suppression
Unusual infections can occur during treatment and afterwards. Report fever, persistent cough, breathlessness, shingles-like blisters or unexplained deterioration promptly. Continue preventive medicines for the full prescribed period.
Severe skin reaction
A spreading painful rash, blisters, peeling skin, or sores in the mouth, eyes or genital area needs urgent medical assessment. Severe reactions may require treatment to be stopped by the team.
A later second cancer
Some chemotherapy medicines can increase the risk of another cancer, including a blood cancer, years later. This is considered when balancing treatment benefits and risks. Keep follow-up appointments and report persistent unexplained symptoms.
Practical advice for this treatment
Use a dated calendar and check each capsule strength. If you vomit after a dose, do not repeat it. If a dose is missed, contact the team for advice and never double up. Take the prescribed anti-sickness medicine before the dose if instructed.
Taking cancer medicines at home
Keep cancer tablets or capsules in their labelled packaging, away from children and pets. Do not share them or put them in a household pill organiser unless the oncology pharmacist agrees. Do not crush, open, split or dissolve them without product-specific pharmacy instructions. A caregiver who handles the medicine should follow the pharmacy’s precautions. Return unused medicine to the pharmacy. If you miss a dose or vomit after one, do not take an extra dose; contact the team and follow the medicine-specific plan. If you accidentally take an extra dose or the wrong strength, contact the oncology team urgently even if you feel well. Do not try to make yourself vomit or work out a compensating dose yourself.
Medicines, interactions and vaccinations
Give the oncology pharmacist a complete list of prescription medicines, over-the-counter products, vitamins, herbal and Ayurvedic remedies and supplements. Ask before starting anything new. Do not stop prescribed medicines, including anticoagulants or infection-prevention medicines, without a coordinated plan. Live vaccines are generally unsuitable while immunity is suppressed; discuss vaccine type and timing with the team. Non-live vaccines may be offered, although protection can be reduced. Follow any specific stop-and-call instructions for the cancer medicine on this page or in your written treatment plan.
Review anticonvulsants, steroids, other medicines affecting blood counts and all supplements. Do not stop anti-seizure medicines or prescribed infection prevention yourself.
Pregnancy, fertility and breastfeeding
Chemotherapy can harm a developing baby and may affect fertility temporarily or permanently. Discuss sperm, egg or embryo storage before treatment when feasible. If you could become pregnant, or your partner could become pregnant, use effective contraception during treatment and for the drug-specific period afterwards. Ask for a written end date based on every medicine in your plan: the required period differs by product and can extend for months. Periods stopping does not guarantee infertility. Tell the team immediately about a suspected pregnancy. Do not breastfeed during treatment; restart only after the team confirms the interval for the exact medicine and formulation.
Everyday life
Gentle activity, regular meals and rest can help you cope. Prepare food hygienically and drink according to your individual fluid plan. Avoid smoking; ask whether alcohol is safe with your exact treatment and other medicines. Plan work, travel and driving around symptoms and monitoring visits. Do not drive if dizzy, sleepy, weak, visually affected or impaired by neuropathy. You can usually be close to family and friends: chemotherapy does not make you radioactive. Follow the unit’s instructions for handling urine, vomit, laundry and sexual precautions for the period it specifies.
When to contact the oncology team
Contact the oncology team the same day for persistent vomiting or diarrhoea, difficulty drinking, reduced urine, mouth pain affecting eating, new cough, jaundice, a painful or spreading rash, unusual bruising, worsening constipation or new nerve symptoms. Use the more urgent instructions for the particular symptom when given above. If the team cannot be reached and you are unwell, seek urgent medical care.
Write down your hospital’s daytime and out-of-hours numbers before treatment. CTI’s general contact details do not replace the emergency number provided by your treating hospital.
After treatment
Keep the planned blood tests and follow-up appointments after the last dose. Blood counts and immunity may take time to recover, and some effects can start or persist later. Contact the team about symptoms rather than waiting for a routine visit. Keep a treatment summary, including drug names, dates and any serious reactions, for future doctors. Response may be assessed with examination, scans or blood or marrow tests, depending on the cancer.
Words you may hear
- Glioma
- A group of tumours that start in supporting cells of the brain or spinal cord.
- Neuroendocrine tumour
- A tumour arising from cells with nerve-like and hormone-producing features. Its grade and site affect treatment.
Frequently asked questions
Do I take it on radiotherapy-free weekends?
Often yes during the continuous concurrent course. Follow your written plan; the later 5-day cycles are different.
Why do I need an antibiotic when I do not have an infection?
During prolonged daily treatment it helps prevent a serious lung infection called Pneumocystis pneumonia.
Will I get every side effect listed?
No. Many people have only some of them. Your dose, other medicines, health and previous treatment all affect risk. Reporting symptoms early often makes them easier to manage.
Does having few side effects mean treatment is not working?
No. Side effects do not reliably show how well cancer treatment is working. The team assesses response using the appropriate tests.
Can a dose be reduced or delayed?
Yes. Blood counts, organ function or side effects may require a delay, reduction, omission or change. The team balances safety with the treatment aim; do not change doses yourself. Follow the specific instructions to stop a medicine and seek help if a warning symptom occurs.
Can I take vitamins, herbal or Ayurvedic products?
Check every product with the oncology pharmacist first. “Natural” does not mean interaction-free, and some products can affect the liver, bleeding or drug levels.
What should I have ready at home?
A thermometer, the 24-hour oncology number, a treatment calendar, your medicine list and prescribed symptom medicines. Arrange help with transport or meals if needed.
When should I call instead of waiting for the next appointment?
Use the urgent-help instructions on this page. Fever, sudden illness, uncontrolled symptoms or difficulty drinking should not wait until the next treatment visit.
Related combination guides
Sources and further reading
Summary of Product Characteristics
Product-specific details vary by formulation and treatment protocol.
Professional reference resources. These describe the specific product, warnings, interactions, monitoring and adverse effects. For US substitutes, the document is prescribing information rather than an SmPC. Check the product actually dispensed in India.
- Temodal capsules — Merck Sharp & Dohme (UK). Accessed 16 October 2026. Original-brand information identified.
Other authoritative references
- Cancer Research UK — Temozolomide. Accessed 16 October 2026.
- NCI — infection and neutropenia. Accessed 16 October 2026.
- NCI — mouth and throat problems. Accessed 16 October 2026.
- NCI — diarrhoea. Accessed 16 October 2026.
- NCI — fatigue. Accessed 16 October 2026.
- BC Cancer — Temozolomide Monograph. Accessed 16 October 2026. Independent cross-check: USES; SPECIAL PRECAUTIONS; SIDE EFFECTS; INTERACTIONS; DOSAGE GUIDELINES.
- ASCO hepatitis B screening and management opinion. Accessed 16 October 2026. Independent cross-check: Provisional Clinical Opinion: universal three-test screening before or at systemic anticancer therapy; chronic/past infection management.
- eviQ — Advanced neuroendocrine cancer: capecitabine and temozolomide. Accessed 18 October 2026. Supports the treatment setting and goal discussed above.
Editorially approved by Dr (Prof) Vijay Agarwal
Professor and Lead Consultant – Medical Oncology
