Dexamethasone is a medicine used to treat a wide range of health conditions. These include:

• severe skin conditions
• severe allergies (anaphylaxis)
• sickness (nausea and vomiting)
• croup
• swelling (inflammation) in your eye
• autoimmune conditions, such as lupus

It's used in hospitals as a treatment for severe cases of COVID-19 (coronavirus) and other serious infections.

It can also help reduce the side effects of cancer treatment, or some of your symptoms if you're having end of life care.

Dexamethasone is a type of medicine called a steroid (corticosteroid). Corticosteroids are a copy of a hormone your body makes naturally. They're not the same as anabolic steroids.

It's available on prescription only and comes as tablets, soluble tablets and as a liquid you drink. It can be given by injection but this is usually only done in hospital.

It also comes as drops and a spray to treat ear and eye infections.

• You usually take dexamethasone tablets or liquid once a day.
• It's best to take it in the morning so it does not affect your sleep.
• The most common side effects are sleep problems, mood changes, indigestion and weight gain.
• Taking dexamethasone tablets or liquid can mean you're more likely to get infections. Tell your doctor if you get an infection, such as coronavirus (COVID-19), or if you come into contact with anyone who has measles, chickenpox or shingles while you're taking dexamethasone.
• If you take dexamethasone for more than 3 weeks, or take more than 6mg a day, you'll get a blue steroid card. You may also need to carry a (red) steroid emergency card. Ask your pharmacist or doctor about both of these.
• You will need to carry a steroid emergency card if you take dexamethasone to treat Addison’s disease, congenital adrenal hyperplasia, other adrenal problems, adrenal insufficiency or hypothalamic or pituitary disorder.

Most adults and children (including babies) can take dexamethasone.

Dexamethasone is not suitable for some people. Tell your doctor before starting on this medicine if:

• you have ever had an allergic reaction to dexamethasone or any other medicine in the past
• you have recently been in contact with someone with shingles, chickenpox or measles
• you have an infection or any unhealed wounds
• you have liver or kidney problems
• you have ever had mental health problems (or a close family member has)
• you have ever had tuberculosis (TB)
• you have high blood pressure, heart failure or recently had a heart attack
• you have diabetes
• you have epilepsy
• you have glaucoma
• you have an underactive thyroid
• you have osteoporosis (thinning bones)
• you have a stomach ulcer
• you have myasthenia gravis, a rare condition that causes muscle weakness
• you have recently had vaccinations, or are due to have vaccinations
• you're pregnant, trying to get pregnant or breastfeeding

Always follow your doctor's instructions when taking this medicine.

Take dexamethasone with after eating a meal or snack, or immediately after eating. Do not take it on an empty stomach.

For soluble tablets, dissolve them in a glass of water then drink it all. For other tablets, swallow them whole with a drink of water.

Liquid dexamethasone comes with a plastic syringe or spoon to help you measure out the correct dose. Do not use a kitchen teaspoon as it will not give you the right amount.

Dosage

Adults – you'll usually take between 0.5mg and 10mg a day. For some conditions the dose can go up to 16mg a day.

Children – doses are usually lower for a child. The doctor will use your child's height and weight to work out the right dose for them.

For treating croup, your child will usually have a single one-off dose.

How often to take it

You'll usually take dexamethasone once a day. Take it in the morning with or immediately after your breakfast.

Unless your doctor gives you different instructions, take your full dose in one go. For example, if your dose is 6mg, your doctor may tell you to take three 2mg tablets at the same time.

If your doctor prescribes dexamethasone 2 or 3 times a day, take your last dose before 6pm. It will be less likely to affect your sleep.

For some conditions you may not need to take dexamethasone every day. Your doctor might tell you to take it every other day instead.

Will my dose go up or down?

If you're taking dexamethasone for longer than a few weeks, your dose may change.

Your doctor may reduce your dose once your symptoms start to get better. If your symptoms get worse again, they may increase your dose again.

Your doctor will probably reduce your dose gradually before you stop completely. This is to reduce the risk of withdrawal symptoms.

What if I forget to take it?

If you take dexamethasone once a day and miss a dose, take it as soon as you remember. If you do not remember until the following day, skip the missed dose and take the next one at the usual time.

If you take it 2 or 3 times a day, take the missed dose as soon as you remember, unless it's less than 2 hours until your next dose. In this case, skip the missed dose and take the next one as normal.

Do not take a double dose to make up for a forgotten one.

If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

Taking 1 or 2 extra dexamethasone tablets as a one-off is unlikely to harm you. If you're worried, talk to your doctor or pharmacist.

If you take too much dexamethasone for more than a few days, it could harm your health. Talk to your doctor as soon as possible.

Like all medicines, dexamethasone can cause side effects, although not everyone gets them.

Side effects are less likely if you are on a lower dose (less than 6mg a day).

Common side effects

Common side effects happen in more than 1 in 100 people.

Keep taking the medicine, but tell your doctor if these side effects bother you or do not go away:

• weight gain
• indigestion
• sleep problems
• mild mood changes

Serious side effects

Serious side effects are more likely with higher doses (more than 6mg a day) or if you take dexamethasone for more than a few weeks or months.

Call a doctor straight away if you get:

• high temperature, chills, a very sore throat, ear or sinus pain, a cough, coughing up more mucus (phlegm) or a change in colour of your mucus, pain when you pee, mouth sores or a wound that will not heal – these can be signs of an infection
• "moon face" (a puffy, rounded face), weight gain in the upper back or belly – this happens gradually and can be a sign of Cushing's syndrome
• a very upset stomach or you're being sick (vomiting), very bad dizziness or passing out, muscle weakness, very tired, mood swings, loss of appetite and weight loss – these can be signs of adrenal gland problems
• sleepy or confused, feel very thirsty or hungry, need to pee more often than usual, flushing, breathing quickly or breath that smells like fruit – these can be signs of high blood sugar (hyperglycaemia)
• muscle pain, weakness or cramps, or your heartbeats suddenly become more noticeable (heart palpitations) – these can be signs of low potassium levels
• severe stomach pain, severe back pain, severe upset stomach or you're being sick (vomiting) – these can be signs of pancreas problems
• swelling or throbbing in your arms or legs, or if you feel breathless or have chest pain – these can be signs of a deep vein thrombosis (DVT) or blood clot
• unexplained bruising or bleeding that is not normal, black poo, or you're vomiting blood or have black or dark brown vomit – these can be signs of internal bleeding
• sudden changes in your eyesight

Children and teenagers

Taking dexamethasone at higher doses for a long time can slow down the normal growth of children and teenagers.

Your child's doctor will monitor their height and weight carefully for as long as they're taking this medicine. This will help them spot any slowing down of your child's growth and change their treatment if needed.

Even if your child's growth slows down, it does not seem to have much effect on their eventual adult height.

Talk to your doctor if you're worried. They'll be able to explain the benefits and risks of giving your child dexamethasone.

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to dexamethasone.

These are not all the side effects of dexamethasone. For a full list see the leaflet inside your medicines packet.

What to do about:

• weight gain – try to eat well without increasing your portion sizes so you do not gain too much weight. Regular exercise will also help to keep your weight stable.
• indigestion – take dexamethasone with a meal or snack to reduce the chances of stomach problems. It may also help to avoid rich or spicy food. If these symptoms carry on, speak to your doctor. They may give you an additional medicine to protect your stomach.
• sleep problems – take dexamethasone in the morning so the levels of dexamethasone in your body are the lowest at bedtime. If you take dexamethasone more than once a day try taking your last dose before 6pm.
• mild mood changes – dexamethasone can affect your mood in different ways. Talk to your doctor if you are finding it hard to cope.

Dexamethasone is not usually recommended in pregnancy.

Steroids have sometimes been linked to problems in the first 12 weeks of pregnancy. Taking them for a long time, or at a high dose, can also affect your baby's growth during pregnancy.

Your doctor may prescribe dexamethasone for you, if they think the benefits outweigh the risks. If you need to take dexamethasone while pregnant, you will have more frequent checks to see how your baby is growing.

Dexamethasone and breastfeeding

You can usually take dexamethasone while you're breastfeeding.

However, dexamethasone can get into breast milk. Ask your doctor or health visitor for advice about breastfeeding while taking this medicine. For this reason, wait at least 3 hours after you take your medicine before breastfeeding your baby or expressing milk.

If you're taking a high dose your baby may need monitoring. This is to make sure they do not have side effects from the medicine.

If you notice your baby is not feeding as well as usual or seems unusually sleepy, or if you have any other concerns about your baby, talk to your health visitor or doctor.

For more information about how this medicine can affect you and your baby during pregnancy, read the leaflet on dexamethasone on the Best Use of Medicines in Pregnancy (BUMPS) website.

Some medicines can affect how dexamethasone works. This can increase your chance of side effects.

Check with a pharmacist or your doctor before starting on dexamethasone if:

• you take medicine for heart or blood conditions, such as warfarin, high blood pressure medicine and tablets that make you pee more (diuretics)
• you take antibiotics such as rifampicin and rifabutin
• you take antifungal medicine
• you take medicine for epilepsy, such as phenytoin, carbamazepine, phenobarbitone and primidone
• you take antacids or other medicine for stomach problems
• you take non-steroidal anti-inflammatory drugs (NSAIDs), such as high-dose aspirin for pain relief, ibuprofen or diclofenac
• you take medicine for HIV
• you've recently had a vaccination, or are due to have one

Mixing dexamethasone with herbal remedies or supplements

There is very little information about taking dexamethasone with herbal remedies and vitamin or mineral supplements.

Not enough research has been done to say whether it's safe.