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At a glance
Megestrol acetate is a medicine used in specialist cancer care. Brand names include Megace. The practical instructions depend on the exact prescription and product supplied.
Your prescription and the instructions for your own product take priority over a general guide. Keep the medicine leaflet as well as your treatment plan, especially if the brand or formulation changes.
You do not need to remember every possible side effect. Start with the administration instructions and the section on urgent help. Most people experience only some of the effects described here. Tell your team about difficulties early: supportive treatment, a planned pause or a different medicine may make treatment easier to continue.
How it works
Megestrol acetate is a progestogen that can be used to treat selected hormone-sensitive cancers. It also has appetite-related effects, but a prescription intended to treat cancer should be distinguished from a prescription intended mainly to manage appetite or wasting.
Is this treatment suitable for me?
The team considers hormone sensitivity, previous treatment, general health and the risk of clots, glucose changes and adrenal suppression. Tablet and suspension products may have different purposes and concentrations. Confirm why it has been prescribed for you.
Your oncologist considers the biology of the cancer, treatments already received, other illnesses and your preferences. The aim may be to reduce the chance of cancer returning, control cancer that is present, or relieve symptoms. Ask which aim applies to you and how benefit will be assessed. The same medicine can be used for different lengths of time in different treatment plans.
A brand name alone does not tell you whether a medicine is suitable. The dose, formulation and other medicines in the plan also matter. Discuss the possible benefits and risks with your care team.
Before treatment
Mention previous thrombosis, diabetes, liver or heart problems, fluid retention and long-term steroid use. Ask the pharmacist to confirm the formulation and strength, especially if you have previously used a liquid appetite medicine.
Bring an up-to-date list of prescription medicines, pharmacy medicines, supplements and traditional or herbal remedies. Include medicines used only occasionally, creams containing hormones, and anything recently stopped. Mention previous allergies and describe what happened, rather than only naming the drug. Your pharmacist can check the whole list together.
Tell the team about any planned operation, dental procedure, travel or difficulty attending appointments. Discuss costs and supply before the first dose if obtaining regular refills may be difficult. Agree who will arrange repeat prescriptions and tests. Keep your own hospital's daytime and out-of-hours contact details where you and a caregiver can find them quickly.
Tell the team about kidney disease. Kidney function may need monitoring, particularly in older people, because impaired clearance can increase adverse effects.
How to take or receive treatment
A common Megace oncology tablet regimen is 160 mg once daily, although schedules depend on the treatment plan. Take with water at a consistent time; food can be used if it helps nausea. Do not substitute a suspension by matching millilitres or assume different suspensions have the same concentration.
If a dose is missed, take it when remembered unless the next is nearly due; then skip it. Do not double. Do not automatically repeat a vomited dose. The break line on some Megace tablets is for ease of swallowing, not for creating equal smaller doses; ask before dividing tablets.
Swallow the medicine as directed for your product. Do not crush, open, dissolve or divide it unless the oncology pharmacist has confirmed a safe method for that exact formulation. Some products have a specific dispersion method; this is different from crushing tablets yourself. Tell the team before starting if swallowing is difficult or you use a feeding tube.
After vomiting a dose, do not automatically take a replacement because some medicine may already have been absorbed. Follow the drug-specific instructions in this section and call the team if vomiting persists. A missed dose and a vomited dose are different situations, so use the relevant rule.
Store tablets or capsules in their labelled packaging, out of children's sight and reach, away from heat and moisture, within the temperature limits on the pack. Keep any drying container supplied in the bottle. Ask before transferring anticancer medicines into an organiser. A caregiver should avoid direct contact with damaged tablets or powder and follow the pharmacy's handling advice; pregnant caregivers should not handle damaged anticancer tablets. Wash hands after handling. Return unwanted doses to a pharmacy rather than putting them into household waste or a drain.
Use a calendar or a phone reminder that records what was actually taken or given. A tick made after a dose is more useful than one made in advance. If someone helps with medicines, agree who records each dose so it is not accidentally repeated. Keep the drug name, strength and current instructions together; an old prescription may no longer describe your current dose.
Contact the treating team if a supply problem or illness is likely to interrupt treatment. Do not stretch the supply by taking smaller doses or lengthening intervals yourself. If you receive too much medicine, seek urgent advice and have the packaging and dose times available. Do not induce vomiting.
Monitoring your treatment
Monitor weight, appetite, swelling and blood sugar as advised. The team assesses treatment response separately from appetite improvement. During prolonged treatment or withdrawal, symptoms suggesting adrenal insufficiency need attention, particularly during infection or surgery.
Monitoring has two purposes: checking whether treatment is helping and detecting problems that may be silent at first. Your schedule depends on the medicine, any partner treatment and your general health. Ask which results need to be reviewed before the next prescription or injection, and who will contact you if a result is abnormal.
Record symptoms that affect eating, walking, sleep or daily activities, along with when they began. Bring this record to appointments. A single symptom or blood result rarely explains the whole picture; the team may compare trends, examination findings and scans. Feeling well is welcome, but it does not remove the need for planned monitoring.
Common side effects
Effects to discuss with your team
Increased appetite and weight gain are characteristic effects. Fluid retention, nausea, mood changes and tiredness can also occur. More appetite does not always translate into stronger muscles or improved nutritional status, so review weight and function together.
Progestogens are medicines related to progesterone. Their anticancer use is distinct from low-dose contraception or treatment for menstrual symptoms. A medicine with the same generic name may have a very different strength, formulation or purpose. Check the exact product whenever a prescription is renewed, and ask the pharmacist to explain any change.
Increased appetite and weight gain can occur. Keep a simple record if your weight changes quickly: gradual appetite-related gain is different from rapid fluid accumulation. Swollen ankles, increasing breathlessness or a rapid weight increase should be discussed promptly. A dietitian can help if eating is difficult or if increased appetite makes diabetes or weight management harder.
These treatments can affect blood sugar and may have steroid-like effects, especially at higher doses or with prolonged use. A rounded face, easy bruising, marked thirst or frequent urination should be reported. Illness, surgery or stopping treatment may require particular attention to adrenal function. Tell emergency staff about current or recent treatment if you develop severe weakness, vomiting, dizziness or collapse.
A history of clots, liver disease, diabetes or heart problems can change the balance of benefit and risk. Do not start aspirin or anticoagulants yourself. Give the team advance notice of major surgery or prolonged immobility so they can decide whether treatment and clot prevention need adjustment.
Making symptoms easier to manage
Tell the team which symptom is causing the most difficulty. Describe its effect on ordinary tasks: for example, whether pain prevents dressing or tiredness stops you preparing food. This helps the team choose practical support and judge whether treatment needs adjustment. Avoid waiting until the next routine visit if symptoms are worsening.
For mild nausea, try smaller meals and regular sips of fluid, following any food rule for the medicine. Ask about an anti-sickness medicine if needed. Repeated vomiting, inability to keep fluids down or very little urine needs prompt advice. If you have been told to restrict fluids for another illness, use that plan rather than forcing extra drinks.
Energy and emotional wellbeing
Pace demanding activities and allow rest, but keep some gentle movement in your day if you can. Persistent exhaustion deserves assessment; poor sleep, anaemia, low mood and other illnesses may contribute. Tell the team about persistent anxiety, sadness or loss of interest. If you feel at risk of harming yourself, seek emergency help and ask someone to stay with you.
Important side effects
The effects below are important because they may require tests or a change in treatment. They are not a prediction that you will develop them. New symptoms can also come from the cancer or an unrelated illness. Reporting them promptly allows the team to work out the cause; do not assume that everything is a routine treatment effect.
Clots, raised glucose or diabetes, steroid-like effects and adrenal suppression are important risks. Adrenal insufficiency may become apparent during treatment or after stopping prolonged therapy. Severe weakness or faintness should not simply be attributed to the cancer.
Blood pressure can rise, and heart failure or a temporary tumour flare with raised calcium can occur. New swelling, breathlessness, worsening tumour symptoms or thirst with confusion needs assessment.
When to get urgent help
Emergency care is needed for sudden chest pain, severe breathlessness, stroke symptoms or collapse. Seek urgent advice for one-sided leg swelling, severe weakness with vomiting or dizziness, marked thirst with confusion, or rapidly increasing oedema.
Get emergency help immediately for severe breathing difficulty, swelling of the tongue or throat, collapse, a seizure, severe chest pain, or signs of a stroke such as a drooping face, new arm weakness or difficulty speaking. Do not drive yourself if you are faint, confused or seriously unwell, and do not wait for an oncology callback before seeking emergency care.
Contact your oncology team the same day for repeated vomiting, dehydration, new jaundice, a rapidly worsening rash, or a sudden major change in how you feel. Fever with shaking chills or feeling acutely unwell also needs prompt advice, particularly if you receive another treatment that can lower white blood cells. Follow the temperature threshold and emergency instructions given for your complete regimen.
When asking for help, give the medicine name, last dose or injection date, other cancer treatments and main symptoms. Mention any blood thinner or steroid. If you cannot reach the team and the problem is urgent, use your hospital's emergency service rather than waiting for the next appointment.
Stop megestrol and seek urgent help for a suspected allergic reaction, particularly a rash with facial or tongue swelling or breathing difficulty. Tell emergency staff about current or recent prolonged treatment because adrenal support may be needed.
Other medicines and vaccinations
Diabetes treatment may need adjustment. The pharmacist should review all medicines, including steroids and anticoagulants. Tell clinicians treating an acute illness or planning surgery about current or recent megestrol because extra steroid support may be needed.
Ask the oncology pharmacist to check new medicines before you start them, including antibiotics prescribed elsewhere. Do not stop essential treatment for another illness on your own. If an interaction is possible, the prescribers can choose an alternative, adjust a dose or arrange monitoring. Herbal products labelled natural can still alter drug levels or have hormone-like effects.
Vaccination advice depends on your complete treatment plan. Hormone treatment alone does not automatically mean that every vaccine is unsuitable. Ask about influenza, COVID-19 and other recommended vaccines; live vaccines need a specific check if you also receive chemotherapy, an immune-suppressing medicine or certain doses of steroid. Tell the vaccination service all the treatments you receive.
Everyday life
Food and movement
Aim for regular meals with enough protein and a varied range of foods that you can tolerate. Tell the team about unplanned weight loss, rapid weight gain or difficulty eating. A dietitian can adapt advice to diabetes, kidney problems, bowel symptoms or a restricted appetite. Do not start a restrictive diet or high-dose supplement as a substitute for treatment.
Choose activity that suits your strength and balance. Short walks or gentle exercises may be easier to sustain than occasional strenuous sessions. If cancer affects your bones, or you have osteoporosis, ask which movements and resistance exercises are safe before starting a new programme. New focal bone pain should be assessed rather than exercised through.
Work and travel
Many people continue some usual activities, but flexibility helps while you learn how treatment affects you. Discuss rest breaks, shorter hours or help with physically demanding work if needed. Avoid driving or operating machinery when dizzy, sleepy, confused or affected by visual symptoms. Follow any additional driving advice after a seizure or loss of consciousness.
Plan travel around prescriptions, injections and tests. Carry an up-to-date medicine list and enough supply for the agreed trip, with advice about storage and time-zone changes. For long journeys, discuss mobility and your individual clot risk. Do not start aspirin or a blood thinner simply because you are travelling.
Relationships and support
Changes in energy, body image or sexual function can affect relationships. You can ask for help privately, with or without a partner present. There may be practical measures or specialist support for discomfort and intimacy. A caregiver can help record symptoms and organise appointments while leaving treatment decisions and personal information under your control.
Fertility, pregnancy and breastfeeding
Avoid pregnancy and use an effective contraception method agreed with the team. Megestrol tablets used for cancer are not dependable contraception. Do not breastfeed during treatment; ask about the appropriate interval after stopping and any additional medicines. Fertility planning should be discussed before treatment.
Tell the team before treatment if having children in the future matters to you. Fertility preservation needs discussion before exposure where possible. Reduced fertility is not the same as reliable contraception, and an absence of periods or reduced sexual function does not prove that pregnancy is impossible.
Ask your team which contraception to use and how long to continue it, taking account of every medicine in your regimen. A partner drug may require a longer precaution period than this medicine alone. If pregnancy is suspected in you or a partner during a risk period, contact the treating team promptly for individual advice. Do not make pregnancy or breastfeeding decisions from a generic time interval without checking your own treatment plan.
After treatment
Do not abruptly stop prolonged treatment without a plan. Ask whether a taper or adrenal assessment is appropriate and what to do if you become ill. Appetite may change again after withdrawal, so ongoing nutritional support may be useful.
Before a planned stop, confirm which medicines end, which continue, and when the next review is due. Return unused medicine through the pharmacy's recommended route; do not give it to another person. Keep a record of the last dose and any side effects that still need follow-up.
Changes caused by treatment may settle gradually, and some need ongoing support. Report persistent symptoms or new problems after treatment rather than assuming they will disappear on their own. Continue the agreed follow-up and screening plan. If treatment is being changed, ask your team to help you update your treatment schedule so that old and new instructions are not accidentally combined.
Common questions
Does a better appetite mean the cancer is shrinking?
Not necessarily. Megestrol can improve appetite independently of an anticancer response. The team assesses cancer control using the appropriate symptoms, examination and tests. Continue follow-up even if eating becomes easier.
Can I swap tablets for a liquid?
Only with a new checked prescription. Suspensions can have different concentrations and may be intended for a different purpose. The pharmacist must confirm the exact product and dose; a millilitre-for-millilitre substitution can be unsafe.
Is all weight gain beneficial?
No. It may reflect increased intake, body-fat changes or fluid retention. Rapid gain, swollen ankles or breathlessness needs assessment. Strength and nutritional status matter as well as the number on the scale.
Why tell emergency doctors that I recently stopped Megace?
Long-term megestrol can suppress adrenal function, and symptoms can appear after withdrawal or during physical stress. Severe weakness, vomiting, dizziness or collapse may require urgent assessment and steroid treatment. Keep the last dose date with your medicine list.
Is this the same as chemotherapy?
It is a hormonal or hormone-related treatment, with a different way of working from conventional chemotherapy. It still needs careful prescribing and monitoring. If chemotherapy or a targeted medicine is part of your plan as well, read the information for that medicine because the combined treatment may have additional risks.
How will I know whether treatment is helping?
Your team will explain which symptoms, blood tests, examinations or scans are useful in your situation. Improvement may take time, and some treatments aim to prevent future problems rather than produce a change you can feel. Keep review appointments even when you feel well.
Does having few side effects mean the medicine is not working?
No. Side effects are not a reliable measure of benefit. People can respond to treatment without feeling particularly different. Equally, having troublesome effects does not prove that the cancer is responding. Decisions should use your clinical assessments and test results.
Can I take a break when I feel tired?
Do not create your own breaks or change the dose. Contact the team about fatigue and explain how it affects your day. They may look for another cause, offer support or prescribe a planned adjustment. A supervised change can be safer than repeated unrecorded missed doses.
How long will I need this medicine?
The duration depends on the aim of treatment, response and tolerability. Some plans have a proposed end date; others continue while the balance of benefit and side effects remains favourable. Ask when this will be reviewed. Another person taking the same medicine may appropriately have a different schedule.
Can I use herbal or Ayurvedic products alongside treatment?
Show the pharmacist the ingredients and exact product before using it. Products may affect hormone activity, liver function or the way medicines are handled in the body. Different preparations with similar names can contain different ingredients. A claim that a product is natural does not establish that the combination is safe.
Should I stop my usual medicines?
Continue them unless a prescriber tells you otherwise, but arrange a full interaction check. Include occasional painkillers, supplements and any newly prescribed medicine. If an interaction is found, the team can agree a safe change without leaving another illness untreated.
What should I do if I need surgery or dental treatment?
Tell both teams about your cancer medicine well in advance. They may need to consider bleeding, clotting, steroid support, bone-protecting treatment or appointment timing. Do not stop treatment based on a general internet rule. Ask your team when to pause and restart treatment, and keep the instructions handy.
Can someone else manage my medicines for me?
Yes, if you want that support. Agree one shared record of doses and appointments and ask the pharmacist about safe handling. A caregiver should know the urgent symptoms and where to seek help. Do not share this prescription with anyone else, even if their diagnosis sounds similar.
What if I cannot obtain the next supply or attend the clinic?
Contact the treating service before treatment is due where possible. Give the drug name, formulation and date of the last dose. The team can address supply or reschedule safely. Do not substitute another hormone medicine, ration tablets or assume a delayed injection has no consequences.
When should I seek help instead of waiting for my review?
Use emergency care for severe symptoms such as breathing difficulty, collapse, chest pain, stroke symptoms or a seizure. Contact the oncology team promptly for a new or worsening problem that affects normal activities. The urgent-help section gives additional signs especially relevant to this medicine.
Sources and further reading
Information checked against the following sources on 28 September 2026. Product names and instructions can differ between formulations and countries; your treating team should confirm the instructions for your supplied medicine.
