Doxycycline: Uses, Side Effects, Dosage

By Zina Semenovskaya, MD
Medically reviewed
December 9, 2021

Doxycycline is a versatile antibiotic used to treat bacterial infections, acne, and more.

This article provides information about the uses, common side effects, proper dosage, and risks of this widely used medication.

What is Doxycycline?

Doxycycline is a frequently usedtetracycline antibiotic.

Tetracyclines can be used to treat infections that are caused by bacteria that are both gram-positive and gram-negative, as well as many other common bacteria types.

Tetracyclines kill bacteria by interfering with their ability to grow.

Tetracyclines are commonly used for many different bacterial infections, including skin infections, sexually transmitted infections (STIs), and even malaria.

Doxycycline is available only by prescription.

It is available in a generic formulation as well as under different brand names, including Morgidox, Doryx, Acticlate, and Avidoxy.

Doxycycline may be prescribed as a capsule, poweder, or in liquid form.

It’s always important to follow the specific instructions on your prescription, as they can vary based on the formulation and dosage that you are prescribed.

If you are prescribed doxycycline, be sure to complete the full course of the antibiotics unless your doctor specifically tells you to stop.

If you don’t complete your prescription, the antibiotics may not fully treat your bacterial infection and may increase your risk of antibiotic resistance. 

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Why is Doxycycline Prescribed?

There are many FDA-approved uses for doxycycline.

Your doctor may prescribe it for any of the following common reasons.

It’s also possible that your health care provider may prescribe it for other reasons not listed here.

If you have questions about why a medication is prescribed, ask your doctor or pharmacist.

Acne

Severe, persistent acne or other skin issues such as rosacea or acne vulgaris that are resistant to other treatment are often treated by dermatologists with tetracycline antibiotics, including doxycycline. 

Urinary tract infections

While rarely the initial choice, Doxycycline can be used to treat urinary tract infections (UTIs).

Most urine samples are cultured to ensure that the correct antibiotic is used.

Doxycycline has advantages because it has broad-spectrum antimicrobial activity and can concentrate effectively in the urine to prevent bacterial replication.

It has lower levels of toxicity than other types of antibiotics and may also be used in some cases to treat multidrug-resistant UTIs that are caused by E. coli or Klebsiella pneumoniae.

Intestinal infections

Intestinal infections can be caused by viruses or bacteria.

If a gastrointestinal illness is determined to be caused by bacteria, it might be treated with doxycycline.

Bacterial gastroenteritis is sometimes referred to as food poisoning.

Contamination can happen from food sources like raw meats, lettuce, poultry, eggs, or dairy, as well as from ingesting contaminated water.  

Respiratory infections

Doxycycline may be used to treat bacterial pneumonia because doxycycline can concentrate in lung tissues, it is especially effective at treating respiratory infections.

Eye infections

In addition to being an antibacterial, doxycycline also exerts an anti-inflammatory effect, making it a good antibiotic for eye infections.

This may help to reduce irritation and keep the eye’s delicate tissues from scarring or otherwise being damaged by ocular bacterial infections.

Doxycycline is effective against eye infections like chlamydial conjunctivitis, which often co-occurs with a genital infection.

It may also be prescribed for severe blepharitis or Meibomian gland dysfunction.

Sexually transmitted infections (STIs)

Sexually transmitted infections (STIs) can be treated with doxycycline.

It may be prescribed for chlamydia, syphilis, and pelvic inflammatory disease, among others.

It works to systematically reduce inflammation and to prevent the replication of bacteria.

Doxycycline may also be used prophylactically to prevent or decrease the risk of developing a STI, like chlamydia or syphilis, though its usage in this context should be carefully discussed with your doctor.

Periodontitis (gum disease)

Doxycycline can be used to treat periodontal disease, which is an infection of the gums.

Doxycycline is effective for periodontitis due to its ability to reduce activity of proteins that affect gum tissue without otherwise destroying normal beneficial oral bacteria.

Malaria

Doxycycline is widely used for malaria both as prophylaxis and as treatment.

For prevention, it is often paired with chloroquine and taken at lower doses for 1-2 days before a trip and during the course of travel.

When treating malaria infections, it is combined with other drugs like quinine or quinidine.

Doxycycline Side Effects

Doxycycline has some common side effects.

They may include:

Other side effects, which are less common but might be more severe, could include:

  • Headache
  • Vision changes like blurry vision, double vision, or loss of vision
  • Hives, rash, or other allergic reactions
  • Skin redness, blistering, or peeling
  • Fever
  • Swollen glands
  • Difficulty breathing or swallowing
  • Swelling of the eyes, lips, throat, tongue, or face
  • Unusual bleeding or bruising
  • Changes to bowel movements, including watery or bloody stools
  • Stomach cramps
  • Joint pain
  • Chest pain
  • Discoloration of permanent teeth
  • Jaundice
  • Dark urine

You should call your doctor if you notice any of these side effects, or if you develop any other new or concerning symptoms.

Use of doxycycline in young children under age 12 is not advised because it can cause tooth discoloration and may impact bone development.

Rarely, it may also lead to brain swelling children.

It should also not be used during pregnancy, breastfeeding, or if you are allergic to tetracycline antibiotics.

How to Take Doxycycline

Your pharmacist will provide you with instructions on how to take your doxycycline prescription.

Be sure to read your prescription label and follow the instructions.

Call your doctor or pharmacy if you have any questions.

Doxycycline can come in different forms and doses, so be sure to follow the specific instructions on your prescription.

It is typically prescribed either once per day or twice per day.

If you take it two times per day, be sure to take the medication 12 hours apart.

What happens if I miss a dose?

If you miss a dose of doxycycline, take it as soon as you realize that you have missed it.

However, if your missed dose is close to your next dose, simply skip it and continue your schedule.

Do not take two doses close together.

What happens if I take too much?

If you take too much doxycycline, call poison control at 1-800-222-1222 or seek emergency medical care.

You should not take double doses or more doxycycline than is prescribed.

If someone has taken too much doxycycline and they have trouble breathing, collapse, or have a seizure, call 911 immediately for medical help.

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What to Avoid While Taking Doxycycline

Doxycycline has many drug interactions.

Don’t change what you are taking without checking with your doctor or pharmacist.

That includes other medications or supplements, as well as over-the-counter drugs.

Iron, calcium, and magnesium supplements should not be taken within two hours of taking doxycycline.

It is important to stay hydrated while taking doxycycline.

Drink plenty of fluids when you take your medicine and throughout the day.

Do not take doxycycline with dairy products, since they may prevent your body from absorbing the medicine.

If you do plan on eating milk, cheese, yogurt, or other dairy products, have them either a few hours before or after taking doxycycline.

Ask your doctor or pharmacist if it is acceptable to consume alcohol while taking doxycycline.

Some research shows that regular alcohol consumption may decrease the effectiveness of the medication or may require higher doses.

Alcohol may also reduce the medication’s ability to do its job, making it harder to reduce bacteria.

Most medical advice recommends avoiding alcohol during antibiotics.

Avoid prolonged sun exposure while taking doxycycline, because it causes temporary skin sensitivity and can increase your risk for sunburn.

If you must be in the sun, wear protective clothing and be sure to use sunscreen.

How K Health Can Help

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Download K to check your symptoms, explore conditions and treatments, and if needed text with a doctor in minutes. K Health’s AI-powered app is HIPAA compliant and based on 20 years of clinical data.

Is doxycycline a strong antibiotic?
Doxycycline is an antibiotic that is frequently used for hard-to-treat infections or those that are resistant to other drugs. It works somewhat differently than other antibiotics, and its potency is determined by dosage and course of treatment.
What is doxycycline used for?
Doxycycline is used for many purposes as both an antibiotic and anti-inflammatory drug. It may be prescribed for acne, sexually transmitted infections, malaria, eye infections, gastrointestinal infections, and more.
What is doxycycline used for most?
Doxycycline is used for common conditions like acne, rosacea, skin or eye infections, sexually transmitted infections, and more. It is beneficial because of its versatile ability to treat several types of bacteria without causing serious side effects.
What are the common side effects of doxycycline?
The most common side effects of doxycycline are similar to those of other antibiotics: stomach upset, loss of appetite, vomiting, changes to bowel movements, dry mouth, and more. It may increase anxiety in some. Read the insert of your prescription to learn more about side effects or speak with your doctor or pharmacist if you have concerns.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.

Zina Semenovskaya, MD

Dr. Semenovskaya specializes in emergency medicine, and received her medical degree from Weill Cornell Medical College. She is currently the medical director at Remote Emergency Medicine Consulting, LLC and splits her time working clinically as an emergency medicine attending in California and Alaska. She is the first of our doctors to be fluent in Russian.