Like all medicines, betamethasone tablets can cause side effects, although not everyone gets them.
You're more likely to get side effects if you take a higher dose. You're less likely to get side effects if you take a low dose of less than 2 tablets a day for less than 3 weeks.
Some side effects, such as indigestion or mood changes, can happen straight away. Others, such as getting a rounder face, can happen after weeks or months of taking betamethasone.
Common side effects
These common side effects of betamethasone tablets happen in more than 1 in 100 people. There are things you can do to help cope with them:
Weight gain
Betamethasone can make you hungrier and retain water, so if you take it for more than a few weeks it's likely that you'll put on weight.
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.
Once you stop taking betamethasone, your appetite and water retention should return to normal.
Indigestion
Take betamethasone tablets with food to reduce the chances of stomach problems. It may also help if you avoid rich or spicy food.
If symptoms do not go away, ask your doctor if you should take an extra medicine to protect your stomach.
Problems sleeping
Take betamethasone in the morning so the levels in your body are lowest at bedtime. Avoid having a big meal, smoking, or drinking alcohol, tea or coffee in the evening. Try not to watch television or use your mobile phone before going to bed. Instead, try to relax for an hour before bedtime.
Feeling restless
If you're restless when you're trying to sleep, take betamethasone in the morning so the levels in your body are lowest at bedtime.
Sweating a lot
Try wearing loose clothing, use a strong anti-perspirant and keep cool with a fan. If this does not help, talk to your doctor as you may be able to try a different medicine.
Speak to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.
Serious side effects
You're more likely to have a serious side effect if you take more than 2 betamethasone tablets a day or if you've been taking it for more than 3 weeks.
Call your doctor or call 111 now if you get:
- a high temperature, a very sore throat, ear or sinus pain, a cough, more saliva or a change in the colour of your saliva, pain when you pee, mouth sores or a wound that will not heal – these can be signs of an infection
- feeling sleepy or confused, feeling very thirsty or hungry, and peeing more often – these can be signs of high blood sugar
- weight gain in your upper back or tummy, a puffy, rounded face (moon face) and slow wound healing – these can be signs of Cushing's syndrome
- feeling or being sick, very bad dizziness or passing out, muscle weakness, feeling very tired, loss of appetite and weight loss – these can be signs of adrenal gland problems
- muscle pain or weakness, muscle cramps, or changes in your heart rate – these can be signs of low potassium levels
- severe stomach pain, severe back pain, feeling or being sick or diarrhoea – these can be signs of pancreas problems
- swelling in your arms or legs
- blurred vision
- any unexplained bruising or bleeding
Immediate action required: Call 999 or go to A&E now if:
- you have breathing problems
- you have black poo, black or dark brown vomit or you're vomiting blood
Mood changes
You may notice mood changes and mental health problems while taking betamethasone tablets.
Call your doctor or call 111 now if you have any mood changes, including:
- feeling depressed
- feeling high, or moods that go up and down
- feeling anxious, having problems sleeping, difficulty in thinking, or being confused and losing your memory
- feeling, seeing or hearing things that do not exist (hallucinations)
- having strange and frightening thoughts, changing how you act, or having feelings of being alone
The higher the dose, the more intense the mood changes can be.
Immediate action required: Call 999 or go to A&E if:
- you have thoughts about harming yourself or ending your life
Serious allergic reaction
It's possible to have a serious allergic reaction to betamethasone (anaphylaxis).
Immediate action required: Call 999 now if:
- your lips, mouth, throat or tongue suddenly become swollen
- you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
- your throat feels tight or you're struggling to swallow
- your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- you suddenly become very confused, drowsy or dizzy
- someone faints and cannot be woken up
- a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Long-term side effects
Children and teenagers
Taking betamethasone for a long time can slow down the normal growth of children and teenagers. This is because it is a steroid.
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 will be able to explain the benefits and risks of giving your child betamethasone tablets.
Other long-term side effects
Taking betamethasone tablets for many months or years can lead to:
- weak bones (osteoporosis)
- diabetes, or worsening of your condition if you already have diabetes
- eye problems
If you need to take betamethasone tablets for a long time, there are steps you can take to stay as healthy as possible.
Take regular exercise and make sure you get enough calcium in your diet to help strengthen your bones. Your doctor may arrange for you to have an occasional bone scan.
If you have diabetes, you may need to check your blood sugar more often. Your doctor can advise you about this.
To reduce the chances of eyesight problems, visit an optometrist every 12 months to check for high pressure in your eye (glaucoma) and cataracts.
Other side effects
These are not all the side effects of betamethasone tablets. For a full list see the leaflet inside your medicines packet.
You can report any suspected side effect using the Yellow Card safety scheme.