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Azithromycin Dihydrate

Zithromax is an antibiotic capsule, and is marketed by Pfizer. It is the branded version of azithromycin, and is used for treating chlamydia.

If you have tested positive for chlamydia, you can get the treatment you need and buy Zithromax online using our secure pharmacy service. Once approved, your medicine will be shipped to you by next-day parcel.

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Zithromax is an antibiotic capsule, and is marketed by Pfizer. It is the branded version of azithromycin, and is used for treating chlamydia.

If you have tested positive for chlamydia, you can get the treatment you need and buy Zithromax online using our secure pharmacy service. Once approved, your medicine will be shipped to you by next-day parcel.

This content was reviewed by a clinician on

19 April 2021
dr daniel

Dr Daniel Atkinson

(GP Clinical Lead - GMC No. 4624794) 19 April 2021
Product information

Zithromax is an antibiotic made by Pfizer. It is the branded version of azithromycin, which is a second line treatment in the UK currently for chlamydia. It is available through our service to patients who have tested positive for this infection and are unable to take Doxycycline, the first line chlamydia treatment. It is also available in combination with a test kit for those who have not been tested for chlamydia yet, but whose partner has tested positive for chlamydia. 

(People who order the combined Zithromax and chlamydia test kit pack online through our site should make sure they collect their urine sample first, before taking the treatment.)

Chlamydia is the most commonly contracted sexually transmitted infection (STI) in the UK. In England alone, there are around 200,000 cases reported each year in GUM clinics. It most commonly occurs in the young adult age group, between the ages of 16 and 24.

The infection is caused by a type of bacteria called C. Trachomatis, and does not always cause symptoms. Around 80 percent of female cases and 50 percent of male cases are asymptomatic. When chlamydia does cause symptoms, these may include pain during urination, as well as vaginal discharge, painful sex, bleeding after sex, bleeding between periods and abdominal pain in women; and pain in the testes and discharge from the penis in men.

This STI can be transmitted through unprotected vaginal, oral or anal sex, or through the shared use of sex toys. Even in cases where it doesn’t cause symptoms, chlamydia should be treated, as it can cause serious complications; such as pelvic inflammatory disease in women, and infertility in both sexes.

Testing for the condition can be carried out using a urine sample, or additionally by taking a swab from the vagina in women. You can either get tested in person at a sexual health clinic, or order test kits online to do yourself at home. You can read more about chlamydia tests on our STI test kits page.

The first line treatment for chlamydia in the UK is Doxycycline. Azithromycin is a second line treatment and is the generic version of Zithromax. It comes in 250mg capsules. 

The antibiotic agent in Zithromax works by preventing the bacteria causing the infection from producing an enzyme it needs to survive. Without this enzyme, the bacteria can no longer spread, and is eventually killed off. This helps to clear the infection.

If you suspect you may have chlamydia and have not been tested, you should arrange to do this as soon as you can. Persons who have a positive test result for chlamydia and are unable to take Doxycycline (if they were allergic to any of its ingredients, for example) can buy Zithromax online using our service. Please note that if you order the treatment on its own, you will be asked during consultation to upload a copy or screenshot of your test result. 

Click ‘buy now’ to get started, and complete our medical questionnaire. Following approval by our doctor, your prescription will be issued and dispensed at our UK pharmacy. Orders are shipped in secure packaging by next-day parcel.

You can also order a combination pack containing a test kit and treatment from us. This is for people who:

  • haven’t been tested yet, but whose sexual partner has received a positive test result for chlamydia (you must take the test before starting treatment if this is the case); or:
  • want to do a test of cure at home two weeks after finishing treatment. And: 
  • are precluded from taking Doxycycline due to medical reasons.

When can I have sex after taking Zithromax?

It's better to wait until you've been re-tested for chlamydia before having sex again, to make sure you don't pass the infection onto someone else. We recommend getting tested for chlamydia again three weeks after taking the treatment, to give the treatment time to work.

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Page last reviewed:  19/04/2021

Make sure when using this treatment that you follow the directions issued by your prescriber, and adhere to the guidelines in the patient information leaflet. This will help you reduce the likelihood of side effects and get the best possible results from the drug.

  1. Use as directed.
  2. You’ll get eight 250mg tablets in total.
  3. To treat chlamydia, take four tablets at the same time on day one.
  4. Take two tablets at the same time on day two.
  5. If you’ve ordered a test and treatment combination pack because your partner has had a positive test result for chlamydia, you should collect your test sample before you start treatment on the first day.
  6. If you have a combination test and treatment pack because you want to do a test of cure (to make sure the infection has gone) after completing treatment, make sure you allow at least three weeks for the treatment to work following completion, before doing your test.
  7. Swallow the capsules whole with a glass of water.
  8. Do not exceed the prescribed amount.

The above is provided only as a summary. More detailed information is available in the leaflet supplied with the product.

If you have ordered the combined test kit and treatment pack because your partner has tested positive for chlamydia, it is very important to collect your urine sample for the test kit BEFORE you take the medicine.


Page last reviewed:  19/04/2021
Please read the patient information leaflet for this medicine fully before use:

Zithromax 250mg

Side effects and warnings

Side effects

Not everyone who uses this medication will experience side effects, but it is still important to be aware of these so that you can act in the event that they occur. Tell your doctor right away if you notice any signs of: an allergic reaction, such as sudden wheeziness, difficulty breathing, swelling of the eyelids, face or lips, or hives; severe diarrhoea accompanied by blood or mucus; skin rash causing redness and flaking; irregular heartbeat; low blood pressure; or any kind of skin reaction.

Very common (1 in 10 people or more):

Stomach cramps, feeling sick, diarrhoea or flatulence.

Common (1 in 10 people or less):

Headache, dizziness, being sick, numbness or pins and needles, indigestion, loss of appetite, taste disturbance, sight problems, deafness, skin rash, itching, pain in the joints, reduced numbers of white blood cells, fatigue or weakness.

Uncommon (1 in 100 people or less):

Oral or vaginal thrush, blistering of the skin, mouth, eyes and genitals, photosensitive reactions, feeling nervous, hypoesthesia, sleeping difficulty, poor hearing or ringing in the ears, palpitations, chest pain, constipation, diarrhoea, fever, hepatitis, abnormal blood or liver function tests, loss of strength, or swelling.

Rare (1 in 1,000 people or less):

Feelings of agitation, or vertigo.

The above is provided only as a summary guide. More detailed information can be found in the leaflet supplied.


Taking it with other medicines

Let your doctor know if you are taking any other treatments when filling in our medical questionnaire. This product may not be suitable for use in conjunction with: ergot or ergotamine; warfarin or any similar drugs used to prevent blood clots; ciclosporin; antacids; digoxin; or terfenadine.

Conditions to look out for

Those with a history of any of the following should seek advice from their prescriber before using this drug, as it may not be suitable, or require use under special instructions: liver or kidney problems; heart conditions; myasthenia gravis; lactose intolerance; diabetes; or migraine.

Pregnancy and breastfeeding

Ask your doctor for advice before using this medicine if you are pregnant or breastfeeding, and have tested positive for chlamydia.

Driving and using machines

It is unlikely that this treatment will inhibit your capacity to drive or use machines.

Lactose intolerance

This medicine contains lactose. Tell your prescriber if you have an intolerance to any sugars.

Page last reviewed:  19/04/2021
Please read the patient information leaflet for this medicine fully before use:

Zithromax 250mg


Can I still drink alcohol?

It is not thought likely to interfere with the function of the drug. However, it may exacerbate any side effects which do occur.

Will I still be able to drive?

Yes, provided you experience no side effects which may make driving difficult or dangerous. If you do, refrain from driving and seek medical advice as soon as possible.

Can I take the medicine while pregnant?

It may not be suitable for those who are pregnant or breastfeeding. Speak to your doctor before taking this or any other treatment in such cases.

How should I store it?

Keep it in a safe place below 30°C.

Am I allergic to anything in the medicine?

In Zithromax capsules are the following: azithromycin, lactose, magnesium stearate, maize starch, sodium lauryl sulphate, gelatin, iron oxide (black) E172, shellac, propylene glycol, sulphur dioxide and titanium dioxide.

Do not use take this treatment if you are allergic to any ingredients listed.

When can I have sex again?

You shouldn't have sex right away after finishing treatment, as it takes time for the treatment to work, and the infection might still be present in your body (and you might pass it on). Once you have taken treatment, we recommend getting tested for chlamydia again after three weeks to make sure the infection has gone. If you test negative for chlamydia, it's safe for you to have sex again.

Is it available over-the-counter?

You will need a prescription in order to be able to buy Zithromax from our online pharmacy. This can be obtained through our remote consultation service, which is staffed by registered practitioners.

Can I buy Zithromax online?

People who think they may have chlamydia but haven’t been tested yet should do so as soon as possible. You can arrange this through your local sexual health clinic, or alternative order a chlamydia test kit online.

Take our questionnaire to order this medication if you have tested positive for chlamydia and cannot take the first line chlamydia treatment, Doxycycline. Order are reviewed by one of our practising doctors before being prepared at our UK pharmacy. We’ll ship your treatment in secure plain packaging, to help ensure your privacy.

Page last reviewed:  19/04/2021 is rated 4.9 out of 5 by 3256 customers on TrustPilot!
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