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Doxycycline 50 mg Capsules Doxycycline 100 mg Capsules – patient leaflet, side effects, dosage

Last updated: · Text from the MHRA, as of · About this document

Medicine status: Prescription only (POM) Details

Medicine strength:
100 mg
Contains active substance:

Patient leaflet - Doxycycline 100 mg capsules

1. WHAT DOXYCYCLINE CAPSULES ARE AND WHAT THEY ARE USED FOR

Doxycycline Capsules contain the active substance doxycycline. Doxycycline is an antibiotic belonging to a group of medicines called tetracyclines. It is used to treat many different types of infections including:

Ÿ Chest, lung or nasal infections e.g. bronchitis, pneumonia, sinusitis

Ÿ Urinary tract infections (the passage through which urine passes) e.g. cystitis, urethritis

Ÿ Acne (a skin condition)

Ÿ Eye infections

Ÿ Sexually transmitted diseases e.g. gonorrhoea, syphilis, chlamydia

Ÿ Fevers associated with louse or tick bites

Ÿ Malaria, when chloroquine is not effective

Doxycycline Capsules are also used to prevent certain infections developing, these are scrub typhus (a disease carried by small insects), Rocky Mountain spotted fever, travellers' diarrhoea, malaria and leptospirosis (a bacterial infection).

Your doctor may want you to take Doxycycline Capsules to treat another infection not listed above. You may also be prescribed an additional medicine to take with Doxycycline Capsules to treat your infection. You must talk to your doctor if you do not feel better or if you feel worse.

2. WHAT YOU NEED TO KNOW BEFORE YOU TAKE DOXYCYCLINE CAPSULES

Do not take Doxycycline Capsules

Ÿ if you are allergic to doxycycline or any other tetracycline antibiotic or any of the other ingredients of this medicine (listed in section 6)

Ÿ if you are pregnant or trying to become pregnant Ÿ if you are breast feeding

You should not use Doxycycline Capsules during periods of tooth development (pregnancy, infancy or in children below 8 years old) as such use may lead to permanent discolouration (yellow-grey-brown).

There may be circumstances (e.g. severe or life-threatening conditions), where your physician may decide that the benefits outweigh this risk in children below 8 years and Doxycycline Capsules should be prescribed.

Warnings and precautions

Talk to your doctor or pharmacist before taking Doxycycline Capsules if any of the following apply to you:

Ÿ you are likely to be exposed to strong sunlight or uv light (e.g. on a sun bed). You should avoid exposure to strong sunlight while taking this medicine as your skin may be more sensitive to sunburn than normal.

Ÿ you have kidney or liver problems.

Ÿ you have myasthenia gravis (a disease which causes unusual tiredness and weakness of certain muscles, particularly in the eyelid).

Ÿ you have an immune system disease that causes joint pain, skin rashes and fever (systemic lupus erythematosus). The condition may be worsened by taking Doxycycline Capsules.

Ÿ you have porphyria (a rare disease of blood pigments). Ÿ you have (or have ever had) systemic lupus erythematosus (an allergic condition that causes joint pain, skin rashes and fever). This condition may be worsened by taking Doxycycline Capsules. Ÿ you are suspected as having syphilis. Your doctor will continue to monitor you after your treatment has stopped. Ÿ you have diarrhoea or usually get diarrhoea when you take antibiotics or have suffered from problems with your stomach or intestines. If you develop severe or prolonged or bloody diarrhoea during or after using Doxycycline Capsules tell your doctor immediately since it may be necessary to interrupt the treatment. This may be a sign of bowel inflammation (pseudomembranous colitis) which can occur following treatment with antibiotics.

Ÿ you are taking oral retinoids as there is a higher risk of suffering from increased pressure in your skull (severe headache with change in vision) when taken with Doxycycline Capsules.

When used for a long duration, Doxycycline Capsules may cause infections that cannot be treated with this antibiotic. Your doctor can explain the signs and symptoms of such types of infection.

Other medicines and Doxycycline Capsules

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines (including medicines you have obtained without a prescription). If you are taking any of the medicines listed below tell your doctor before taking Doxycycline Capsules.

Some medicines can reduce the effectiveness of Doxycycline Capsules, these include:

Ÿ Antacids (indigestion remedies), iron preparations, oral zinc or bismuth. These should not be taken at the same time of day as Doxycycline Capsules.

Ÿ Carbamazepine, phenytoin (medicines used to control epilepsy) and barbiturates (used to control epilepsy or as a sedative) and rifampicin (medicine used to treat tuberculosis).

Doxycycline Capsules can affect the action of some other medicines, these include:

Ÿ Increased action of warfarin or coumarins (used to prevent blood clots)

Ÿ Reduced effectiveness of oral contraceptives (birth control pills)

Ÿ Reduced effectiveness of penicillin antibiotics (used to treat infections)

Ÿ Increased blood levels of ciclosporin (a medicine used to affect the body's immune response)

If you are going to have a general anaesthetic for an operation or dental surgery you must tell your anaesthetist or dentist that you are taking doxycycline as you may have more side effects.

Taking Doxycycline Capsules with food, drink and alcohol

Please see section 3 'How to take Doxycycline Capsules'. Alcohol may reduce the effect of Doxycycline Capsules and should be avoided.

Pregnancy and breast-feeding

If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby ask your doctor or pharmacist for advice before taking this medicine. Doxycycline Capsules must not be taken if you are pregnant or breast-feeding.

Driving and using machines

This medicine should not affect your ability to drive or use machines.

3. HOW TO TAKE DOXYCYCLINE CAPSULES

Always take this medicine exactly as your doctor or pharmacist has told you to. Check with your doctor or pharmacist if you are not sure.

Ÿ The capsules should be swallowed with plenty of water. Ÿ It is best to take your capsules at the same time(s) each day, when sitting or while standing.

Ÿ It is important not to lie down for at least thirty minutes after taking Doxycycline Capsules, so that the capsule can move as swiftly as possible into the stomach and prevent irritation of the throat or oesophagus (canal taking food from the mouth to the stomach). Ÿ For the treatment of infections, Doxycycline Capsules can be taken with or without food.

Ÿ For the treatment of acne, it is recommended to take Doxycycline Capsules with food or a drink.

Ÿ If Doxycycline Capsules upset your stomach then taking it with food or milk is recommended.

The recommended doses are shown in the list below. These are the different doses that your doctor may prescribe depending on the infection being treated. Usual Dose (Chest, lung or nasal, urinary tract, eye and other infections)

200 mg on the first day, then 100 mg daily. The length of treatment is dependent on the infection being treated. Children aged 8 years to less than 12 years

Doxycycline for the treatment of acute infections in children aged 8 years to less than 12 years should be used in situations where other drugs are not available or are not likely to be effective. In such circumstances, the usual doses are:

Ÿ For children 45 kg or less

First day: 4.4 mg for each kg of bodyweight (in single or 2 divided doses) then 2.2 mg for each kg of bodyweight (in single or 2 divided doses) from the second day. The length of treatment is dependent on the infection being treated. In more severe infections, up to 4.4 mg for each kg of bodyweight should be given throughout treatment. Ÿ For children over 45 kg

Dose administered for adults should be used; 200 mg on the first day, then 100 mg daily. The length of treatment is dependent on the infection being treated.

Ÿ Adults and children aged 12 years to less than 18 years

200 mg on the first day, then 100 mg daily. The length of treatment is dependent on the infection being treated. Acne

50 mg daily for 6-12 weeks, with food or a drink. Sexually Transmitted Diseases

100 mg twice daily for 7 - 10 days.

Primary and Secondary Syphilis

200 mg twice daily for 2 weeks. Your doctor will continue to monitor you after your treatment has stopped. Fevers associated with louse or tick bites

Single dose of 100 mg or 200 mg depending on severity. Treatment of malaria, when chloroquine is not effective

200 mg daily for at least 7 days.

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Cyan

NOT TO BE PRINTED

Prevention of malaria

100 mg daily from 1-2 days before travelling to a malarial area until 4 weeks after returning.

Prevention of scrub typhus

Single dose of 200 mg.

Prevention of travellers' diarrhoea

100 mg twice daily on the first day of travel, followed by 100 mg daily throughout the stay in the area. If you are planning to take these capsules for more than 21 days, please consult your doctor.

Prevention of leptospirosis

200 mg once each week during the stay in the area; 200 mg on completion of the trip. If you are planning to take these capsules for more than 21 days, please consult your doctor.

Treatment of Rocky Mountain spotted fever

Adults: 100 mg every 12 hours.

Children weighing less than 45 kg: 2.2 mg/kg body weight given twice a day.

Children weighing 45 kg or more should receive the adult dose.

Patients should be treated for at least 3 days after the fever subsides and until there is evidence of clinical improvement. Minimum course of treatment is 5 – 7 days.

You should start to feel better within a few days. If you have been given Doxycycline Capsules for acne it may be a few weeks before you start to see an improvement. If your infection gets worse or you do not start to feel better within a few days (except for acne), or a new infection develops, go back and see your doctor.

If you take more Doxycycline Capsules than you should

If you take too much Doxycycline Capsules contact your doctor or nearest hospital immediately. Always take the labelled medicine package with you, whether there is any Doxycycline Capsules left or not.

If you forget to take Doxycycline Capsules

If you forget to take a capsule take it as soon as you can. Take your next capsule at the right time. Do not take a double dose to make up for a forgotten dose.

If you stop taking Doxycycline Capsules

If you stop taking the capsules too soon, the infection may return. Take the capsules for the full time of treatment, even when you begin to feel better. If you have any further questions on the use of this medicine, ask your doctor or pharmacist.

4. POSSIBLE SIDE EFFECTS

Like all medicines, this medicine can cause side effects, although not everybody gets them.

Stop taking this medicine and tell your doctor immediately if you experience any of the following serious side effects after taking this medicine. Although they are very rare, the symptoms can be severe.

Ÿ Sudden wheeziness, difficulty in breathing, chest pain, fever, swelling of eyelids, face or lips, rash or itching (especially affecting the whole body).

Ÿ Upset stomach, loss of appetite, severe, persistent or bloody diarrhoea (this may occur up to two or three months after the last dose and may be associated with stomach pain or fever). This may occur after treatment with antibiotics and can be a sign of serious bowel inflammation.

Ÿ Fever, swollen lymph nodes or skin rash. These may be symptoms of a condition known as DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms) and can be severe and life-threatening.

Ÿ Very severe headache which may be associated with visual disturbances such as blurred vision, double vision or loss of vision. Permanent visual loss has been reported. The possible symptoms in benign intracranial hypertension include headache, vomiting, visual disturbances including blurred vision, a localised defect in the visual field bordered by an area of normal vision (scotoma), double vision (diplopia), and possible vision loss, in some cases, even permanent.

Ÿ Serious illness with widespread severe blistering of the skin, mouth, eyes and genitals.

If any of the side effects listed below occur, contact your doctor as soon as possible.

Ÿ The Jarisch-Herxheimer reaction which causes fever, chills, headache, muscle pain, and skin rash that is usually self-limiting. This occurs shortly after starting doxycycline treatment for infections with spirochete such as Lyme disease.

Ÿ Skin that is more sensitive to sunlight than normal. You may get a skin rash, itching, redness or severe sunburn. If this happens stop taking the medicine and tell your doctor.

Ÿ Inflammation and/or ulcers of the gullet.

Ÿ Blood disorders. These are due to changes in numbers of different cell types in the blood. Symptoms may include tiredness, easy bruising or infections.

Ÿ Low blood pressure.

Ÿ Increased heart rate.

Ÿ Aches in the joints or muscles.

Ÿ Stomach pain and diarrhoea.

The side effects listed below may go away during treatment as your body adjusts to the medicine. Tell your doctor if any of these side effects continue to bother you:

Common: may affect up to 1 in 10 people

Ÿ feeling or being sick

Ÿ worsening of a disease called systemic lupus erythematous (SLE). This is an allergic condition which causes joint pain, skin rash, fever and headache Ÿ pericarditis (inflammation affecting the heart)

Uncommon: may affect up to 1 in 100 people

Ÿ heartburn

Ÿ vaginal infection

Rare: may affect up to 1 in 1,000 people

Ÿ anxiety

Ÿ difficulty in swallowing, sore or painful tongue or mouth Ÿ skin reddening (flushing)

Ÿ a ringing or buzzing noise in the ear

Ÿ soreness and itching of the rectal and/or genital area Ÿ inflammation of the bowel

Ÿ bulging fontanelles (soft spot on head) of infants Ÿ increased pressure in the skull (severe headache with change in vision)

Ÿ inflammation and damage to the liver

Ÿ abnormal liver function tests

Ÿ discolouration of the thyroid tissue when given for long periods. The medicine does not impair thyroid function Ÿ round or oval patches of redness and swelling of the skin which reappear at the same site each time the medicine is taken (fixed eruption)

Ÿ darker patches on your skin

Ÿ loosening of the nail from the nail bed after exposure to the sun

Ÿ increased levels of urea in the blood

Ÿ yellow skin and eyes (jaundice), inflammation of the pancreas

Ÿ upset stomach, loss of appetite, diarrhoea (this may occur up to two or three months after the last dose), stomach pain

Not known: frequency cannot be estimated from the available data

Ÿ discolouration and/or lack of growth of teeth

Reporting of side effects

If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects, you can help provide more information on the safety of this medicine.

5. HOW TO STORE DOXYCYCLINE CAPSULES

Keep this medicine out of the sight and reach of children.

Do not use this medicine after the expiry date which is stated on the carton and blister after EXP. The expiry date refers to the last day of that month.

This medicine does not require any special storage conditions.

Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.

If your capsules become discoloured or show any other signs of deterioration, consult your pharmacist who will tell you what to do.

6. CONTENTS OF THE PACK AND OTHER INFORMATION What Doxycycline Capsules contain

Ÿ The active substance is doxycycline (as hyclate). Ÿ Each 100 mg capsule contains 100 mg of doxycycline (as hyclate).

Ÿ The other ingredients are:

  • Capsule content: Hypromellose, Sodium lauryl sulphate, Microcrystalline cellulose, Magnesium stearate.
  • Capsule shell: Gelatin, Titanium dioxide (E171), Brilliant Blue (E133), Quinoline Yellow (E104), Sunset Yellow (E110), Sodium lauryl sulphate.

Ÿ Each 50 mg capsule contains 50 mg of doxycycline (as hyclate).

Ÿ The other ingredients are:

  • Capsule content: Hypromellose, Sodium lauryl sulphate, Microcrystalline cellulose, Magnesium stearate.
  • Capsule shell: Gelatin, Titanium dioxide (E171).

What Doxycycline Capsules look like and contents of the pack

Doxycycline 100 mg Capsules are green, size “2” hard, gelatin capsules containing a yellow granular powder. Doxycycline 50 mg Capsules are white, size “4” hard, gelatin capsules containing a yellow granular powder. Doxycycline 100 mg and 50 mg Capsules are available in blister packs of 6, 8, 10, 14, 20, 28, 30, 50, 56, 60, 84 and 90 capsules.

Not all pack sizes may be marketed

Marketing Authorisation Holder

Dawa Limited, 5 Sandridge Cl, HA1 1XD, UK.

Manufacturer

Drugsrus Limited, 5 Sandridge Cl, HA1 1XD, UK. This leaflet was last revised in August 2026.

Blind or partially sighted? Is this leaflet hard to see or read? Call 020 8423 2111 to obtain the leaflet in a format suitable for you.

170.00 mm

About this document

Source: MHRA - Medicines and Healthcare products Regulatory Agency (products.mhra.gov.uk) · Marketing authorisation: PL 30684/0242

Last revision stated in the text: August 2026 · MHRA data as of 13 October 2026

Found a mistake? Tell us on the contact page.

The information on this site does not replace the advice of a doctor or pharmacist.

Facts about Doxycycline 100 mg capsules

Prescription needed? Yes, prescription-only medicine (POM)
Active substance Doxycycline
Strength 100 mg
Pharmaceutical form Oral capsule
Green, size “2”, hard gelatin capsules (18 mm x 6.5 mm) containing a yellow granular powder.
How is it taken Oral
Excipients Hypromellose, Sodium lauryl sulphate, Microcrystalline cellulose, Magnesium stearate, Gelatin, Titanium dioxide (E171), Brilliant Blue (E133), Quinoline Yellow (E104), Sunset Yellow (E110)
Is it available? Listed as available (NHS Dictionary of Medicines and Devices – not a record of current supplies)
Shelf life 3 years.
Storage This medicinal product does not require any special storage conditions.
Drug group (ATC) Tetracyclines
  1. J Antiinfectives for systemic use
    1. J01 Antibacterials for systemic use
      1. J01A Tetracycline antibiotics
        1. J01AA Tetracyclines
          1. J01AA02 doxycycline
Marketing authorisation PL 30684/0242 (first authorised 4 March 2025)
Marketing authorisation holder Dawa Limited
Codes BNF 05010300

Sources: the MHRA product information (products.mhra.gov.uk) and the NHS Dictionary of Medicines and Devices (dm+d), release 10.1.0 of 12 October 2026, NHS Business Services Authority. Contains public sector information licensed under the Open Government Licence v3.0.