Doxycycline side effects and how to avoid them

In this article:

• Common side effects of doxycycline
• Serious side effects of doxycycline
• How soon do doxycycline side effects start?
• How long do doxycycline side effects last?
• What are the long-term side effects of doxycycline?
• How to avoid doxycycline side effects
• Bottom line: Is doxycycline hyclate safe?

In this article

• Common side effects of doxycycline
• Serious side effects of doxycycline
• How soon do doxycycline side effects start?
• How long do doxycycline side effects last?
• What are the long-term side effects of doxycycline?
• How to avoid doxycycline side effects
• Bottom line: Is doxycycline hyclate safe?

Doxycycline hyclate is a widely used antibiotic that treats many bacterial infections, including respiratory tract infections, urinary tract infections, and sexually transmitted infections. It’s also a first-line treatment for Lyme disease and can be used for severe acne. It belongs to a group of medications called tetracycline antibiotics, which fight bacteria by blocking their growth. Like all antibiotics, doxycycline may cause side effects, some of which may be serious.

Common side effects of doxycycline

Most people taking doxycycline don’t typically experience severe adverse effects. Side effects are usually mild and go away after treatment or as the body gets used to the drug. Some of the most common side effects of doxycycline may include:

• Upset stomach
• Diarrhea
• Sore throat or throat irritation
• Stomach cramps
• Loss of appetite
• Anxiety
• Vomiting
• Headache
• Yeast infection
• Sensitivity to UV light or sunlight
• Skin discoloration
• Tooth discoloration

Serious side effects of doxycycline

The most serious side effects of doxycycline are:

• Liver problems
• Kidney problems
• Inflammation of the pancreas (pancreatitis)
• Inflammation of the lining of the heart (pericarditis)
• Esophagitis or esophageal ulcer
• Blood disorders, such as hemolytic anemia, thrombocytopenia, and neutropenia
• Increased pressure in the skull (intracranial hypertension or pseudotumor cerebri)
• Clostridium difficile overgrowth and severe diarrhea
• Severe skin reactions (Stevens-Johnson syndrome, exfoliative dermatitis, toxic epidermal necrolysis, or erythema multiforme)
• Severe allergic reactions, which may cause difficulty breathing or a severe skin rash

This may not be a complete list of possible side effects. Read the prescription label and consult a doctor, pharmacist, or other healthcare provider to discuss potential side effects of doxycycline. 

How soon do doxycycline side effects start?

Some of doxycycline’s side effects begin early in treatment, like nausea or an upset stomach. An allergic reaction could also happen rapidly after the first dose, while other severe side effects are linked to long-term use of the drug. However, doxycycline is often taken over a fairly short period, usually a week to 10 days.

How long do doxycycline side effects last?

Mild doxycycline side effects, like nausea or rash, go away soon after stopping the medicine. More serious side effects, such as severe diarrhea, esophagus irritation, and rare skin and blood reactions, can take longer and may need medical care. Sun sensitivity may last for a short time after treatment. In young children, tooth discoloration can be permanent.

What are the long-term side effects of doxycycline?

Doxycycline hyclate isn’t usually taken long-term. However, the most serious concerns are antibiotic resistance, which can lead to superinfections, and overgrowth of C. difficile, which can cause severe diarrhea. Both are serious and even life-threatening risks, so long-term treatment is often avoided. Some people do, however, take doxycycline over the long term, particularly for acne or rosacea. In those cases, healthcare providers may order regular lab tests to make sure the medicine isn’t causing harm.

Doxycycline contraindications

Doxycycline should be avoided in anyone with a known allergy or hypersensitivity to any ingredients in the drug. 

Pregnancy

Because of the risk to an unborn baby, 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 and slowed bone growth. 

Children

Doxycycline and other tetracycline antibiotics are usually avoided in children under 8 years old. An exception is made for serious, potentially life-threatening infections such as anthrax or Rocky Mountain spotted fever. These drugs can affect developing teeth, leading to enamel defects and discoloration.

Doxycycline warnings

All antibiotics should be used carefully. Although they’re effective drugs, they can also cause serious problems. 

• Teeth discoloration: Taking doxycycline during pregnancy, infancy, or before age 8 can cause permanent tooth discoloration (yellow, gray, or brown) and sometimes weak enamel. It should only be used in young children when absolutely necessary.
• Bone growth: In babies and young children, doxycycline may slow bone growth. This usually improves once the medicine is stopped.
• Severe diarrhea (C. difficile infection): Like many antibiotics, doxycycline can cause a serious intestinal infection that may appear during treatment or even up to two months later. It can range from mild diarrhea to life-threatening colitis.
• Sun sensitivity: Doxycycline can make the skin extra sensitive to sunlight, leading to a serious sunburn. 
• Severe skin reactions: Rare but serious reactions (such as Stevens-Johnson syndrome, toxic skin reactions, or widespread rashes) have been reported.
• Pressure in the head (intracranial hypertension): Doxycycline can, in rare cases, increase pressure inside the skull, causing headaches, blurred or double vision, or even vision loss. This risk is higher in women of childbearing age, people who are overweight, or those also taking isotretinoin.
• Kidney effects: Tetracyclines can raise blood urea nitrogen (BUN), but this effect has not been shown to worsen kidney function in people taking doxycycline.
• Malaria prevention: Doxycycline helps prevent malaria but doesn’t fully block the parasite. People taking it can still pass malaria on to mosquitoes.
• Antibiotic resistance: Using doxycycline when it’s not truly needed can make bacteria resistant, making future infections harder to treat.
• Other infections: Long-term use may allow non-susceptible bacteria or fungi to overgrow, which can cause new infections that require different treatments.

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 determined by a healthcare provider.

Doxycycline interactions

Like many prescription drugs, doxycycline can interact with other medicines and affect how well either one works. Some drug interactions can increase side effects, while others can make doxycycline less effective.

• Retinoids: Taking doxycycline with a retinoid, like isotretinoin, could increase the risk of intracranial hypertension, or increased fluid pressure in the brain. Retinoids should be avoided while taking doxycycline. 
• Blood thinners: Doxycycline can slow down blood clotting, so blood thinners such as warfarin may need to have their dosages reduced.
• Penicillins: Doxycycline may reduce the ability of penicillins to kill bacteria, so the combination is generally avoided.
• Antacids and iron supplements: Antacids with aluminum, calcium, or magnesium, as well as bismuth subsalicylate and iron supplements, can block doxycycline from being absorbed. Doxycycline should be taken at least 2 hours before or after these medicines.
• Birth control pills: Doxycycline may reduce the effectiveness of oral contraceptives, so an extra method of birth control is recommended while taking this antibiotic.
• Live vaccines. Doxycycline may reduce the effectiveness of the BCG or cholera vaccines.
• Seizure medicines and barbiturates: These medications can shorten the half-life of doxycycline, causing the body to clear it faster and lowering its effectiveness. Seizure medications include phenytoin and carbamazepine, while barbiturates include phenobarbital and pentobarbital. 
• Lab tests: Doxycycline can sometimes cause false results in urine tests for catecholamines.

How to avoid doxycycline side effects

Doxycycline side effects are generally mild and temporary. Still, taking certain steps may help prevent problems.

1. Share your full health history with your provider

Let your healthcare provider know about all of your medical conditions, especially if you have liver or kidney disease, or if you are pregnant, planning pregnancy, or breastfeeding. It’s also important to mention specific drugs you’re taking, such as blood thinners and retinoids. 

2. Take it with plenty of water

Swallow each dose with a full glass of water and stay upright for at least 30 minutes. This reduces the chance of throat irritation or esophageal ulcers.

3. Avoid bedtime dosing

Taking doxycycline right before lying down increases the risk of esophageal irritation. Try to take it earlier in the day or evening.

4. Take it with a meal

Taking doxycycline on an empty stomach may cause nausea and stomach upset. Consider taking doxycycline with a small meal (excluding dairy products) to help prevent digestive side effects. 

5. Protect the skin from sunlight

Doxycycline can make the skin more sensitive to sunlight and UV light, which may lead to severe sunburn. Avoid tanning beds, limit sun exposure for several days after stopping the drug, and use protective clothing plus high-SPF sunscreen while taking it.

6. Complete the prescribed course

Unless serious side effects occur, take the full course of doxycycline even if you’re feeling better. In most cases, the symptoms of the infection will clear up in a few days after starting doxycycline. However, stopping early can allow the infection to return. Never take extra doses beyond what your doctor prescribed.

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 may require medical attention.

Headaches

Headaches can be improved by drinking fluids and resting. Before taking over-the-counter pain relievers, ask your healthcare provider for medical advice. Severe or persistent headaches should be reported immediately. 

Nausea

Stay hydrated and sip fluids if you feel sick to your stomach after taking doxycycline. If vomiting is severe or does not improve, contact your healthcare provider.

Diarrhea

Drink plenty of fluids to prevent dehydration. Seek emergency care if diarrhea is severe, watery, bloody, or accompanied by abdominal pain. In rare cases, dangerous infections can develop weeks or months after finishing doxycycline.

Increased pressure in the brain

Severe headaches and dizziness are symptoms of a potentially serious side effect of doxycycline. Seek immediate medical help if these symptoms develop. Symptoms to particularly watch out for are blurred or double vision and pain behind the eyes.

Sunlight reactions

Doxycycline should be stopped if direct sunlight causes an unusual skin reaction. Symptoms include rash, redness, itching, or severe sunburn. Immediately contact a healthcare provider for guidance. 

Severe skin or allergic reactions

Allergic and skin reactions can rapidly turn into serious and even life-threatening medical emergencies. Symptoms of an allergic reaction or severe skin reaction include:

• Hives
• Swelling of the face, throat, or mouth
• Rash, blistering, or peeling
• Trouble breathing or swallowing
• Fever, flu-like symptoms, sore throat, muscle pain, or weakness
• Easy bruising

Serious reactions may be a medical emergency. Consult a healthcare provider and go to the nearest emergency room if these symptoms arise. 

Bottom line: Is doxycycline hyclate safe?

Doxycycline is a safe and effective antibiotic when used as prescribed, especially for the short-term treatment of infections. While most side effects are mild, rare instances of serious reactions have been reported, particularly with longer-term use. 

Consider taking the tablets with food and plenty of water, and let your care team know about medical conditions you have or other medications you take, including dietary supplements and herbal products. If you notice new symptoms or have questions about the use of this medication, reach out to your healthcare provider before making any changes to your treatment.