Doxycycline is a broad-spectrum antibiotic used to treat various infections, including those of the chest, dental, and skin. It belongs to the tetracycline class of antibiotics. Doxycycline is the first-line treatment for chlamydia in the UK and is available as oral capsules that contain 100mg of doxycycline.

Doxycycline works for chlamydia by killing the bacteria responsible for the infection. It does this by stopping them from making the proteins they need to survive. Because it is a broad-spectrum antibiotic, it can be effective against many types of bacteria and used to treat several different infections.

At Superdrug Online Doctor, we only provide doxycycline 100mg capsules for the treatment of chlamydia or to prevent malaria.

How effective is doxycycline for treating chlamydia?

Doxycycline is the first-line treatment for chlamydia in the UK. Research shows that it is:

• 95% effective after 7 days
• 94% effective with a 3-day course

When compared to another antibiotic, azithromycin, doxycycline was shown to be 100% effective for urogenital chlamydia infections compared to 97% with azithromycin.

To take doxycycline for chlamydia, capsules should be:

• swallowed whole with plenty of water
• taken at the same time each day, either while sitting or standing, and around 8 to 12 hours apart
• taken with or without food

Most commonly, doxycycline is prescribed twice per day. It’s recommended to avoid lying down for 30 minutes after taking them to prevent irritation in your throat or oesophagus (food pipe).

How long does doxycycline take to work?

Most people will feel better or notice an improvement in their symptoms within a few days, but you should finish your course even if you feel better. If you do not complete your course, there is a risk that the infection may not have cleared or could return.

What if I throw up after taking doxycycline?

Being sick (vomiting) is a common side effect of doxycycline. If you become sick while taking this medication, contact your doctor for advice. If doxycycline does upset your stomach, it can help to take it with food or milk.

What if I miss a dose?

If you forget to take a doxycycline 100mg capsule, take it as soon as you remember. Doses must be taken 8 to 12 hours apart when taken twice a day. If it’s almost time for your next dose and you will not have time to take another tablet today, skip the missed dose.

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

The usual dose of doxycycline for chlamydia is 200mg daily. This should be taken as a single 100mg capsule, twice a day, for 7 days. For maximum effectiveness, take the capsules at the same time each day and around 12 hours apart. Most people find it easiest to take 1 capsule in the morning and 1 in the evening.

If you are taking doxycycline for any other infections, the dosage may be different. Speak to your pharmacist if you are unsure or check your prescription.

Doxycycline is a prescription-only medication, so you will need a doctor’s approval to get it. You may be able to get it on the NHS or privately via a reputable online doctor service after you have tested positive for chlamydia. Your doctor may carry out tests during your appointment, or you can choose to do an at-home chlamydia test.

Can I buy doxycycline online?

Yes, doxycycline for chlamydia can be requested online via Superdrug Online Doctor. Our service is quick, discreet, and completely confidential.

To request doxycycline online, you will need to:

1. Complete a short online questionnaire.
2. Sign up or log in to your account.
3. Choose your preferred treatment.
4. A doctor will review your request to determine if treatment is suitable for you.
5. If your request is approved, your treatment can be posted to you or a local Superdrug Pharmacy for collection.

Our chlamydia service makes it easy to get the treatment you need quickly, without having to attend a walk-in clinic or take time off work to attend an appointment. We can diagnose and treat chlamydia, and this can all be done from the comfort of your own home, without ever needing a face-to-face appointment.

Can I buy doxycycline over the counter?

No, you will need a prescription from a doctor to obtain doxycycline, so it cannot be bought over the counter.

Can I get doxycycline on the NHS?

Yes, you may be able to get doxycycline on the NHS, but you will need to make an appointment with your doctor or visit a sexual health clinic to get tested and find out if it’s available and safe for you to take.

Like all medications, doxycycline can cause side effects, although not everyone will get them.

Common doxycycline side effects include:

• feeling or being sick
• worsening of lupus
• inflammation of the heart (pericarditis)

Uncommon side effects include:

• heartburn
• vaginal infection

Rare side effects include:

• anxiety
• difficulty swallowing
• sore or painful tongue
• flushing
• ringing or buzzing in the ears
• soreness around the genitals or anus
• bowel inflammation
• increased pressure in the skull
• liver inflammation and/or damage
• loose nails after sun exposure
• yellowing of the skin or eyes
• pancreatitis
• upset stomach
• loss of appetite
• diarrhoea
• dark patches on your skin

A full list of side effects can be found in the patient information leaflet that is supplied with your medication.

How long do doxycycline side effects last?

Most mild doxycycline side effects can last a few days to a few weeks, depending on how long you need to take it for.

What to do if you get doxycycline side effects

Most mild side effects can be managed at home by:

• drinking plenty of water to prevent dehydration and manage effects like headaches and feeling sick
• taking over-the-counter painkillers, such as paracetamol or ibuprofen
• eating simple, bland meals that do not contain spices or are not rich
• taking the medication with food or milk, especially if it is causing an upset stomach

If you get any of the following serious side effects, stop taking doxycycline and see a doctor straight away or go to A&E in an emergency:

• sudden wheeziness, difficulty breathing or swallowing, chest pain, fever, swelling of the eyelids, face, or lips, skin rash or itching (a severe allergic reaction)
• worsening symptoms of systemic lupus erythematosus (SLE)
• sign of serious bowel inflammation, such as upset stomach, severe or persistent bloody diarrhoea, and a loss of appetite (this can happen up to 3 months after your last dose)
• very bad headache and vision changes
• increased pressure in the brain
• widespread blistering of the skin, mouth, eyes, and genitals

You must also speak to your doctor straight away if you get the following side effects:

• a Jarisch-Herxheimer reaction, with symptoms like fever, headache, skin rash, and muscle pain
• your skin is more sensitive to sunlight or UV light than normal, which can cause itching, redness, a skin rash, or severe sunburn – stop taking the medicine and tell your doctor
• aches in the muscles or joints
• blood disorders, with symptoms that may include feeling tired, bruising easily, or infection
• low blood pressure
• increased heart rate
• inflammation or ulcers of the oesophagus
• stomach pain and diarrhoea

Doxycycline may not be suitable for everyone. It is important that you tell your doctor about any other health conditions you have or any other medications you are taking before you start a course of doxycycline.

Do not take doxycycline if you are:

• allergic to doxycycline, any other tetracycline antibiotics, or any other ingredients in the medication
• pregnant or trying to get pregnant
• breastfeeding

Tell your doctor before taking doxycycline if you:

• are going to be exposed to strong sunlight or UV light while taking the medications
• have kidney or liver problems
• have myasthenia gravis
• have porphyria
• have or have ever had systemic lupus erythematosus (SLE)
• think you may have syphilis
• have diarrhoea or get diarrhoea when you take antibiotics
• are taking retinoids
• have an inflamed oesophagus

Other medications and doxycycline

Doxycycline capsules must not be taken if you are:

• taking penicillin
• going to receive the anaesthetic methoxyflurane

Before taking doxycycline, let your doctor know about any prescribed, over-the-counter, or herbal medications you are currently taking or plan to take. Some medications can reduce the effectiveness of doxycycline, such as:

• antacids
• carbamazepine
• phenytoin
• barbiturates

The following medications can be affected by doxycycline:

• blood-clotting drugs
• oral contraceptive pills
• antacids or iron preparations
• preparations containing zinc
• bismuth salts
• ciclosporin

Doxycycline and alcohol

Alcohol can reduce the effectiveness of doxycycline and should be avoided during the course of your treatment.

Doxycycline and pregnancy/breastfeeding

Doxycycline must not be taken if you are pregnant, trying to get pregnant, or breastfeeding, as it can cause problems with the colour and development of your baby’s teeth and the development of their bones.

Doxycycline is the first-line treatment for chlamydia. However, if you cannot take doxycycline or it is not tolerated well, a doctor may prescribe azithromycin.

Azithromycin is a macrolide antibiotic which works by killing the bacteria causing the infection. Like doxycycline, it is a prescription-only medication, which means you will need a doctor's approval to get it.

Azithromycin is given as a single 1g dose followed by 500mg once a day for 2 days, whereas doxycycline is usually given for 7 days, and it is 97% effective at clearing chlamydia.

If you are pregnant, you may be given the following chlamydia treatments:

• azithromycin
• erythromycin
• amoxicillin

At Superdrug Online Doctor, we only prescribe doxycycline for chlamydia.

Can doxycycline cure gonorrhea?

No, the first-line treatment for gonorrhoea in the UK is a 1g intramuscular injection of the antibiotic ceftriaxone. If you have a needle phobia or you cannot take ceftriaxone, you may be prescribed oral treatments such as gentamicin, cefixime, azithromycin, or ciprofloxacin, but doxycycline is not the right antibiotic for a gonorrhoea infection.

Can I drink alcohol while taking doxycycline for chlamydia?

No, it is best to avoid alcohol while taking doxycycline for chlamydia because it can reduce the antibiotic’s effectiveness and increase the chance of side effects.

Should I get retested for chlamydia after taking doxycycline?

No, if you have taken your doxycycline course as prescribed, there is no need to retest after completing your treatment. You should only retest if you think you have been exposed to chlamydia again. If you are still getting symptoms, your doctor may prescribe another course of antibiotics without a retest.

When can I have unprotected sex again?

You should avoid having sex until you and your current sexual partner have finished doxycycline treatment.

Can I take doxycycline if I take oral contraception?

Yes, doxycycline does not interfere with the effectiveness of hormonal contraception, but if you are sick or get diarrhoea while taking it, your contraceptive pill may be less effective. You should follow the instructions in the patient information leaflet for your pill. If you are sick and consider an extra method of contraception, like condoms, while you are taking doxycycline.

Can doxycycline affect your period?

No, doxycycline is not known to have a direct impact on your menstrual cycle, but factors like illness, stress, or routine changes can cause period changes like late or heavy periods. If you are concerned, speak to your doctor for advice.