Doxycycline is a very versatile antibiotic medicine in the form of a tablet. Chemically classified as tetracycline, this medicine is a generic version of branded Vibramycin-D, originally developed by Pfizer. It is used with exceptional success in the treatment of numerous bacterial infections, including chlamydia. In some cases, it can also be used for malaria prophylaxis if one is travelling to high-risk regions of the world.

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Chlamydia: General information

Chlamydia ranks as the single most common sexually transmitted infection in the UK with around 200.000 new diagnoses being made each year and accounting for roughly a half of all STI cases in the United Kingdom. As a very contagious disease, chlamydia can be transmitted through vaginal, oral and anal sex as well as through the use of shared sex toys. As its name, derived from ancient Greek word for “cloak” implies, chlamydia can remain “hidden”, that is, completely symptomless in a significant portion of those affected, making it that much harder to diagnose. It is estimated that around 50% of affected men and as much as 80% of affected women won’t notice any of the characteristic symptoms.

In those cases where they do manifest, chlamydia will be marked by vaginal or penile discharge, irregular bleeding in women and testicular pain in men. However, even when it is asymptomatic, untreated chlamydia can lead to numerous health complications, with some of them being rather dangerous and severe. These include pelvic inflammatory disease in women or fertility issues in both sexes. This is why it is important to get regularly tested if you are sexually active.

Doxycycline as a chlamydia treatment

According to NICE guidelines, chlamydia treatment should, in the first line, include Doxycycline and Azithromycin, with Doxycycline being somewhat more common in those cases where the infection occurs in the rectum. It can also be used for treatment of genital infection, but in this scenario it is prescribed only when Azithromycin isn’t suitable for one reason or another. While Azithromycin is a one-off dose antibiotic, Doxycycline needs to be taken twice per day over the course of one week.

Can I buy Doxycycline online?

Yes, it is possible to buy Doxycycline online, but you will still need to be issued a prescription for this to happen. The easiest way to get the prescription and purchase the medicine in one go is to use the services of a certified online clinic. There you will be able to talk to a doctor online – most commonly, a customized questionnaire will be presented for you and then used to determine whether you are suitable for your prefer treatment. Once a medical professional has approved the treatment, the medicine will be sent to your address within the timeframe outlined in the online clinic’s business model.

If you haven’t been tested for chlamydia, but suspect you might have been exposed, you can also obtain an at-home STI test kit online, usually through the same online clinic which you might later use to order the treatment if needed. As an alternative, you might choose to visit your doctor in person or maybe a local GUM or STI clinic.

If your sexual partner has been tested positive, but you haven’t tested yet, you should do so as soon as possible, so you can commence the treatment early and thus prevent any possible further complications.

Doxycycline in malaria treatment and prevention

Doxycycline is also prescribed as an antimalarial medicine in some cases due to its ability to combat the plasmodium parasite that is the culprit for malaria onset. However, there are several strains of malaria in different parts of the world, so Doxycycline might not be the best option for all of them. More info regarding this can be found on the NHS Fit for Travel website.1

How is Doxycycline used?

As with all prescription medication, the best way to ensure the success of the treatment while at the same time minimizing the risks of side effects is to follow the directions provided by your doctor exactly. In addition to this, further guidelines and advices can be found in the patient information leaflet that is issued within every box of Doxycycline.

Most general guidelines can be presented as follows:

  • Follow the directions exactly
  • The commonly prescribed dose for chlamydia treatment is 100mg (taken twice per day over the course of one week)
  • Take the tablets whole with water
  • Don’t exceed the prescribed amount
  • Don’t drink alcohol while taking this medicine and for additional 48 hours after completion of the treatment
  • Do not take larger doses in order to compensate for a missed dose – instead continue the treatment as usual, but contact your doctor for advice

What are Doxycycline side effects?

All medicines come with certain risk of adverse effects and the same is true for Doxycycline. Even though side effects of this medicine are very rare, it is still important to get familiar with them prior to the beginning of treatment so you can notice them early on if they do appear and contact your doctor who will probably suggest an alternative treatment that is more suitable for you. Of course, allergic reaction to the medicine or one of its components is something that everyone should be aware of, as this side effect will require you to seek immediate medical attention.

Possibly the most unconventional side effect of Doxycycline is its ability to make people’s skin more sensitive to sunlight, so if you are using this medicine, it would be advisable to avoid direct exposure to sunlight. If it is unavoidable, then a high-factor sun-block should be used.

Some of the documented side effects include:

  • Changes in the number of blood cells and subsequent nosebleeds and bruising
  • Porphyria
  • Headache
  • Increased cranial pressure
  • Tinnitus
  • Vision problems
  • Loss of appetite
  • Stomach pain and discomfort
  • Heartburn, diarrhoea and stomach ulcer
  • Stevens-Johnson syndrome
  • Muscle and joint pain

For full list of documented side effects, please consult the patient information leaflet.

Doxycycline contraindications

There are several scenarios where your doctor might advise you against using doxycycline in chlamydia treatment. Adverse interactions with other medicines you might be using are one of these examples. Anticoagulants, penicillin, rifampicin, antacids, medicines containing iron, zinc, epilepsy medicines and oral contraceptives can all interact with Doxycycline in potentially harmful ways.

Doxycycline will also not be suitable for you if you have or had some of the following conditions:

  • Liver diseases
  • Porphyria
  • Myasthenia gravis
  • Sensitivity to sunlight
  • Lupus

It is also important to note that taking Doxycycline when pregnant or breastfeeding might not be advisable if it can be avoided, so be sure to consult with your doctor if this might be the case. Finally, this medicine should never be mixed with alcohol and you should refrain from drinking for additional 48 hours after the completion of your treatment.


  1. Fit for travel – NHS