Doxycycline is an antibiotic that's used to treat infections including:
- chest and dental infections
- skin infections and conditions like rosacea
- sexually transmitted infections (STIs)
- other rare infections
It can also be used to prevent malaria if you're travelling abroad.
Doxycycline is available on prescription. It comes as capsules, tablets and tablets which dissolve in water (dispersible).
Who can take doxycycline
Doxycycline is usually taken by adults and children over 12 years old. For some infections, doxycycline can be taken by younger children.
Doxycycline is not suitable for some people. To make sure it's safe for you, tell your doctor if you:
- have ever had an allergic reaction to doxycycline or any other medicine
- have kidney or liver problems
- have an inflamed food pipe (oesophagitis)
- have lupus, an autoimmune disease
- have myasthenia gravis, a condition that causes severe muscle weakness
- are pregnant or breastfeeding
Your dose of doxycycline depends on why you are taking it. The usual dose is 100mg to 200mg, taken once or twice a day.
You might take a lower dose, such as 40mg once a day or 20mg twice a day, for rosacea or gum infections.
Children younger than 12 years old may need to take a lower dose than adults. The dose depends on your child's age and weight. If you're taking doxycycline more than once a day, try to space your doses evenly throughout the day.
Dose for malaria
You'll usually take 100mg once a day in the morning.
Carry on taking doxycycline until you've completed the course, even if you feel better. If you stop your treatment early, the infection could come back, or you may no longer be protected against malaria.
If you're taking a lower dose of 40mg of doxycycline a day for rosacea or gum infections, take it at least 1 hour before food.
If you're taking a higher dose of 100mg or more for other types of infection, you can take it with or without food. But you're less likely to feel sick if you have it with food.
Do not take your medicine together with dairy products. This is because dairy foods like milk, cheese and yoghurt can stop your body from absorbing doxycycline. You can have dairy products a few hours before or after your dose.
It's important to take doxycycline while you're in an upright position. You can be sitting, standing or walking. This will stop the medicine irritating your food pipe or stomach. Avoid lying down for at least 30 minutes after taking doxycycline.
If you take it twice a day, this could be first thing in the morning, and in the evening – before you go to bed. Try to avoid lying down for at least 30 minutes after taking doxycycline. This helps to prevent any irritation.
If you're taking doxycycline for malaria, start your treatment 1 or 2 days before going to an area with malaria. Stop taking it 4 weeks after leaving the area. Check with your doctor or pharmacist that doxycycline is the best medicine to prevent malaria in the country you are travelling to.
How to take capsules or standard tablets
Swallow your doxycycline whole with at least 150ml of water. Not swallowing them with enough water can cause swelling and irritation in your throat (oesophagitis).
How to take dispersible tablets
Dissolve the tablet in a small amount of water. Let the tablet break up fully then swallow the drink.
If you forget to take it
If you forget to take a dose, take it as soon as you remember, unless it's nearly time for your next dose. If that happens, just leave out the dose you missed and take your next dose at the usual time.
Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.
If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to remember to take your medicines.
If you take too much
Taking 1 extra dose of doxycycline is unlikely to harm you. But speak to your pharmacist or doctor if you're worried, or you have taken more than 1 extra dose.
Common side effects
These common side effects of doxycycline happen in around 1 in 10 people. There are things you can do to help cope with them:
Speak to a doctor or pharmacist if the advice on how to cope does not help and the side effect is still bothering you or does not go away.
Serious side effects are rare and happen in less than 1 in 1,000 people.
Contact 111 or call a doctor now if you have:
- bruising or bleeding you cannot explain (including nosebleeds), a sore throat, high temperature and feeling tired or generally unwell – these can be signs of blood problems
- diarrhoea (possibly with stomach cramps) that contains blood or mucus – if you have severe diarrhoea that lasts longer than 4 days, also speak to a doctor
- ringing or buzzing in your ears
- pale poo and dark pee, and the whites of your eyes turn yellow or your skin turns yellow (although this may be less obvious on brown or black skin) – these can be signs of liver problems
- joint or muscle pain since starting doxycycline
- severe headaches, vomiting and problems with your vision – these could be signs of pressure around your brain (intracranial hypertension)
- a fingernail that starts coming away from its base – this could be a reaction to sunlight called photo-onycholysis
- a sore or swollen mouth, lips or tongue
- severe pain in your stomach, with or without bloody diarrhoea, nausea and vomiting – these can be signs of pancreatitis
- difficulty or pain when you swallow, a sore throat, acid reflux, a smaller appetite or chest pain which gets worse when you eat – these could be signs of an inflamed food pipe (oesophagitis) or oesophageal ulcer
Serious allergic reaction
In rare cases, doxycycline can cause a serious allergic reaction (anaphylaxis).
These are not all the side effects of doxycycline. For a full list see the leaflet inside your medicines packet.
Doxycycline and pregnancy
Doxycycline is not recommended during pregnancy. It can affect tooth and bone development in your baby. Talk to your doctor about taking a different antibiotic.
If your doctor or health visitor says your baby is healthy, you can take doxycycline for a short time (less than 3 weeks) while breastfeeding.
Doxycycline passes into breast milk in fairly small amounts. However, the calcium in your milk sticks to the doxycycline so the baby cannot absorb very much.
When used for a short time, doxycycline is unlikely to cause side effects in your baby. When used for longer, there is a small chance that it can affect teeth and bone development. However, this has only happened when babies have been given doxycycline directly. It has not happened when babies have doxycycline through breast milk.
If you need to take doxycycline for longer than a few weeks, talk to your doctor or pharmacist.
If your baby is not feeding as well as usual, has a rash, has stomach upset, or has oral thrush (a fungal infection in their mouth), or if you have any other concerns about your baby, talk to your doctor, pharmacist, health visitor or midwife.
Doxycycline and fertility
There's no clear evidence to suggest that taking doxycycline reduces fertility in either men or women.
Speak to a pharmacist or your doctor if you're trying to get pregnant, as doxycycline is not recommended in pregnancy and other treatments may be more suitable.
Cautions with other medicines
There are some medicines that do not mix well with doxycycline. Before taking it, tell your doctor if you're already taking any of these medicines:
- indigestion remedies (antacids)
- stomach ulcer medicines that contain bismuth such as Pepto-Bismol
- other antibiotics, such as rifampicin
- acne medicines containing vitamin A, such as isotretinoin
- warfarin, a medicine to help prevent blood clots
- medicines for epilepsy, such as phenytoin or carbamazepine
- ciclosporin, a medicine that calms down your immune system
A typhoid vaccine given by mouth (orally) may not work properly if you're taking doxycycline. It is OK to have the typhoid vaccine that comes as an injection when taking antibiotics, as it is not a live vaccine.
Tell your doctor if you're taking any supplements including:
- anything which contains aluminium, bismuth, calcium, magnesium or zinc
- iron supplements
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