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Doxycycline side effects and how to avoid them

Doxycycline side effects include photosensitivity
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By | Oct. 26, 2022 Medically reviewed by Anne Jacobson, MD, MPH
Hand holding blue Rx pill: Doxycycline side effects and how to avoid them

Key takeaways

  • Doxycycline is an antibiotic used to treat a wide range of bacterial infections. Common side effects include nausea and photosensitivity; in rare cases, serious conditions like blood disorders and liver dysfunction may occur.

  • Photosensitivity, a notable side effect of doxycycline, causes increased skin sensitivity to UV radiation and potentially leads to severe sunburn or skin reactions.

  • You can minimize the risk of doxycycline side effects by taking the medication as directed, avoiding sun exposure, and informing your healthcare provider about all medical conditions and current medications.

  • Most side effects of doxycycline improve after discontinuation of the drug, but serious side effects may require longer recovery times or additional medical treatment.

In this article:

Doxycycline is a generic prescription antibiotic used to treat a broad spectrum of bacterial infections including respiratory tract infections, urinary tract infections, chlamydia, gonorrhea, acne, rosacea, typhus, and some infections normally treated by penicillin, like syphilis. Doxycycline is also one of the first-line treatments for early Lyme disease. 

Doxycycline belongs to a class of drugs called tetracycline antibiotics. These drugs fight off bacteria by blocking their ability to make the proteins they need to grow and reproduce. Doxycycline is also known by a wide variety of brand names including Vibramycin hyclate, Vibra-Tabs, Doryx, and Acticlate. Other doxycycline brands like Oracea and Monodox contain a slightly different form of the drug called doxycycline monohydrate. Like all antibiotics, doxycycline has some side effects and other possible problems people should be aware of.

Common side effects of doxycycline

Most people taking doxycyclinewill not have significant adverse effects. The most common side effect is nausea. Others side effects include:

  • Upset stomach
  • Flu or flu-like symptoms
  • Diarrhea
  • Sore throat or throat irritation
  • Cough
  • Stuffy sinuses
  • Muscle pain
  • Back pain
  • Stomach cramps
  • Anxiety
  • Nasal congestion
  • Vomiting
  • Headache
  • Yeast infection
  • Inflammation of the lining of the heart
  • Dry mouth
  • Sensitivity to sunlight
  • Skin discoloration
  • Tooth discoloration
  • Loss of appetite
  • Kidney dysfunction

Serious side effects of doxycycline

The most serious side effects of doxycycline are:

  • Blood disorders
  • Liver dysfunction
  • Swelling of the pancreas
  • Esophagitis or esophageal ulcer
  • High pressure within the skull (intracranial hypertension or pseudotumor cerebri)
  • Clostridium difficile overgrowth and diarrhea
  • Autoimmune reactions
  • Severe drug reactions
  • Severe allergic reactions

Doxycycline and photosensitivity

While the exact incidence isn’t known, doxycycline can make the skin more sensitive to ultraviolet (UV) radiation like sunlight. Exposure to sunlight could cause skin rash, skin discoloration, itching, redness, or a bad sunburn. It can happen in just a few minutes or take a few hours. Additionally, the skin can remain sensitive to UV radiation for up to two days after the drug is discontinued. This reaction may be from doxycycline building up in the skin. People taking doxycycline should generally avoid sunlight or tanning beds. When it’s necessary to go outside, always wear high-SPF sunscreen and cover as much skin as possible with protective clothing. Immediately stop taking doxycycline and contact a healthcare provider if there are any symptoms of a skin reaction due to sunlight exposure.

How soon do doxycycline side effects start?

Some of doxycycline’s side effects begin early in treatment, like nausea or upset stomach. An allergic reaction could happen rapidly after the first dose. More serious side effects are delayed, but doxycycline is often taken over a fairly short period, usually a week to 10 days.

How long do doxycycline side effects last?

Doxycycline side effects generally improve once the medicine is stopped, usually in two or three days. Some serious side effects may take much longer to get better even with treatment. These include blood disorders, pancreatitis, C. difficile diarrhea, esophageal ulcers, or a severe drug or skin reaction. Tooth discoloration caused by doxycycline in children could last throughout the child’s life.

What are the long-term side effects of doxycycline?

Like all antibiotics, doxycycline is not commonly used for long durations. The most serious adverse event of long-term treatment is the growth of antibiotic-resistant bacteria or the overgrowth of C. difficile in the colon. Both are serious and even life-threatening risks, so long-term treatment is generally avoided. Some people do, however, take doxycycline over the long term, particularly for acne or rosacea. In those cases, healthcare providers are advised to regularly perform lab tests to make sure the body’s organs are healthy, particularly the kidneys, liver, and blood.

Doxycycline contraindications

Doxycycline is never prescribed to people who are allergic to the drug.

Pregnancy

Because of the risk to the fetus, doxycycline and other tetracycline antibiotics are generally avoided during pregnancy, particularly in the second and third trimesters. Exceptions can be made for women with anthrax or with malaria when other treatments don’t work.

Breastfeeding

Breastfeeding is not recommended in women who are taking doxycycline or for five days after the last dose. Doxycycline is present in human breast milk and could cause serious side effects in the nursing infant such as tooth discoloration, inhibition of skeletal growth, and yeast infections. 

Children

Doxycycline and other tetracycline antibiotics are generally avoided in children younger than 8 years old except in cases of life-threatening infections such as anthrax or Rocky Mountain spotted fever. Doxycycline can interfere with tooth development, resulting in imperfect enamel growth and permanently discoloring the teeth.

Seniors

Initial clinical trials and later experience have suggested that doxycycline is as safe and effective in seniors as in other people. However, healthcare providers in general are cautious when prescribing antibiotics to people older than 65 because of issues with declining liver and kidney function.

Doxycycline warnings

All antibiotics should be used carefully. They’re beneficial drugs but they can also cause problems. 

Cautions

Women of childbearing age are at risk for developing increased pressure in the brain, called intracranial hypertension if they have a history of intracranial hypertension or excessive body weight. It should only be used cautiously in people with a recent history of intestinal inflammation after taking antibiotics.

Abuse, dependence, and withdrawal

Doxycycline is not a drug that people abuse. It does not cause physical dependence or withdrawal symptoms.

Overdose

Get emergency medical treatment or call a poison control center if too much doxycycline is taken. If taking doxycycline at home, the typical dosage is 100 mg once or twice per day, but doses will be individualized.

Doxycycline interactions

As with all prescription drugs, doxycycline can cause problems when combined with other drugs. Some drug interactions can worsen adverse effects and can reduce the effectiveness of either doxycycline or other drugs. 

  • Retinoids. Taking doxycycline with a retinoid, like isotretinoin, could increase the risk of intracranial hypertension, or increased fluid pressure in the brain. At least one, acitretin, is never combined with a tetracycline antibiotic because of the risk.
  • Blood thinners. Doxycycline can slow down blood clotting, so blood thinners such as warfarin may need to have their dosages reduced.
  • Penicillins. In general, doxycycline reduces the ability of penicillins to kill bacteria, so the combination is generally avoided.
  • Antacids. Any antacid containing aluminum, calcium, magnesium, bismuth subsalicylate, or iron—and that accounts for just about every antacid out there—interferes with the body’s ability to absorb doxycycline through the intestines. Each doxycycline dose must be taken at least two hours before or two hours after taking an antacid.
  • Metals. The same applies to any drug containing metals like iron, calcium, magnesium, aluminum, zinc, or bismuth. Doxycycline bonds with these metals and then passes through the intestines without being absorbed. Dietary supplements containing manganese or zinc cause the same problem. The rule is the same: a doxycycline dose must be taken two hours before or two hours after any of these drugs or supplements.
  • Birth control pills. Oral contraceptives are less effective at preventing pregnancy when doxycycline is taken.
  • Live vaccines. Doxycycline may reduce the effectiveness of the BCG or cholera vaccines.
  • Drugs that speed up the body’s elimination of doxycycline. Some drugs shorten the half-life of doxycycline, making it less effective at fighting off bacterial infections. These include some seizure medications, barbiturates, and others. Healthcare providers are aware of these drugs and will adjust treatments accordingly.

How to avoid doxycycline side effects

Doxycycline side effects are generally mild and relatively infrequent. Still, a few smart moves can help prevent problems.

1. Tell the prescriber about all medical conditions and medications

The primary way to avoid doxycycline side effects is to tell the prescribing healthcare provider about pre-existing medical conditions and all drugs being taken including over-the-counter drugs and supplements. The most important to include are:

  • Liver problems
  • Kidney problems
  • A history of high pressure in the brain
  • Any use of retinoid drugs
  • Any use of blood thinners
  • Pregnancy or plans to become pregnant
  • Breastfeeding or plans to breastfeed

2. Take doxycycline as directed

Follow the prescriber’s instructions. Take each dose as prescribed and according to schedule. Take each dose with a full glass of water to prevent possible throat irritation or other problems.

3. Do not miss doses

Although missing a dose will not cause side effects, it will reduce the benefits of taking doxycycline. It also increases the risk of growing bacteria resistant to doxycycline. In case a dose is missed, take it when remembered. However, if it’s almost time for the next dose, skip the missed dose and take the next dose on schedule. If doses are missed regularly, ask the pharmacist for advice or useful reminder tools.

4. Take all the prescribed doses

Unless there’s a serious side effect or reaction, take all prescribed doses for the full period. In most cases, the symptoms of the infection will clear up in a few days. However, the entire course of treatment is required to make sure that all the bacteria are cleared out.

5. Do not use doxycycline for other infections

Doxycycline only works on bacterial infections and a few parasite infections. It will not work against fungal or viral infections. 

6. Eat plain foods

To avoid nausea, vomiting, and stomach upset, switch to a diet of plain and simple foods while taking doxycycline. 

7. Avoid antacids

Even if doxycycline causes stomach upset or nausea, avoid antacids. The metals in antacids interfere with the body’s ability to absorb doxycycline. That’s a win for the bacteria. Take antacids two hours before or two hours after the doxycycline dose.

8. Avoid some supplements

Many dietary supplements (and drugs) contain metal salts like zinc, manganese, magnesium, iron, and so on. These will also reduce the ability of the digestive system to absorb a dose of doxycycline. Before taking multivitamins or metal-containing supplements, ask the prescriber first.

9. Don’t take the doxycycline doses before bedtime

Taking doxycycline tablets or capsules before going to bed could cause esophagus problems or sores. Avoid lying down for 30 minutes after taking doxycycline.

10. Protect the skin from sunlight

To avoid skin reactions or sunburn due to doxycycline, try to stay out of the sun as much as possible. Tanning beds should be avoided outright. If it’s necessary to go outside, cover as much skin as possible with clothing. Use high-SPF sunscreen.

How to treat side effects of doxycycline

Not all side effects are avoidable. Most improve with simple treatments at home, but a few side effects will require medical attention.

Headaches

Headaches can be improved by drinking fluids and resting. Before taking over-the-counter pain relievers, ask the prescriber for medical advice. If headaches are severe, immediately contact the prescriber.

Nausea

Doxycycline is not taken with a meal, so the best way to handle nausea and vomiting is to drink fluids. If vomiting is severe or doesn’t go away, contact the prescriber.

Diarrhea

Drink fluids to avoid dehydration. If diarrhea is severe, watery, bloody, or accompanied by abdominal pain, get emergency medical treatment. Severe diarrhea can happen weeks or months after the end of doxycycline treatment and is a sign of a serious secondary infection.

Increased pressure in the brain

Changes in vision, severe headaches, and dizziness are symptoms of a potentially serious side effect of doxycycline. Immediate medical attention is required. Symptoms to particularly watch out for are blurred vision, seeing double, and pain behind the eyes.

Sunlight reactions

Doxycycline should be stopped if sunlight causes an unusual skin reaction. Symptoms include rash, redness, itching, or sunburn. Immediately contact the prescriber or other healthcare professional.

Drug or allergic reactions

Stop taking doxycycline and call a healthcare professional if experiencing an allergic or drug reaction. Skin reactions can rapidly turn into serious and even life-threatening medical emergencies. Symptoms of a severe skin or allergic reaction include:

  • Hives
  • Swelling of the face, throat, or mouth
  • Skin rash
  • Trouble breathing
  • Trouble swallowing
  • Flu-like symptoms
  • Fever
  • Severe sore throat
  • Muscle pain
  • Skin pain
  • Weakness
  • Blistering
  • Peeling skin
  • Bruises

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