What are the most common side effects of doxycycline?
The most common side effects of doxycycline are listed below. Tell your healthcare provider if you have any of these side effects that bother you.
- Loss of appetite
- Nausea
- Vomiting
- Diarrhea (see below)
- Rash or hives
- Sensitivity to sunlight (see below)
There may be other side effects of doxycycline that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of doxycycline?
While less common, the most serious side effects of doxycycline are described below, along with what to do if they happen.
Antibiotic-associated Diarrhea. An overgrowth of germs called Clostridioides difficile, or “C. diff,” can happen in your gut with many types of antibiotics, including doxycycline. This can cause a condition known as antibiotic-associated diarrhea and can happen even up to 2 months after stopping the antibiotic. Call your healthcare provider right away if you have any of the following symptoms of this condition.
- Watery diarrhea
- Diarrhea that does not go away
- Blood in your stool (poop)
- Severe stomach cramps
- Fever that starts after you start or finish the medicine
Severe Allergic Reactions. Doxycycline can cause allergic reactions, including DRESS which can be serious. DRESS stands for Drug Reaction with Eosinophilia and Systemic Symptoms. It is also sometimes called multi-organ hypersensitivity. This is a reaction that can affect multiple parts of the body including your liver, kidneys, and heart. Stop taking the medicine and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching, skin rash, or pale red bumps on the skin called hives
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
- Swelling in your feet, ankles, or legs
- Dark colored urine
- Your skin or the whites of your eyes turning yellowish in color (also called jaundice)
Severe Skin Reactions. Doxycycline can cause severe skin reactions called Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN), exfoliative dermatitis, and erythema multiforme that can lead to death if not treated. If you develop a rash, stop doxycycline and call your healthcare provider right away. Get emergency help right away if you have any of the following symptoms.
- Painful red or purple skin that looks burned and peels off
- Flat or raised red, pink, or purple rash or blisters on your skin, mouth, nose, and genitals
- Red, painful, watery eyes
Sensitivity to Sunlight. Your skin may be very sensitive to light from the sun and devices that give off similar light, such as sunlamps and tanning beds, while you are taking certain drugs, including doxycycline. This is called photosensitivity. Use sunscreen and wear a hat and clothes that cover your skin if you need to be in the sunlight. Exposing your skin to this kind of light, even for a short time, can cause your skin to be severely sunburned, blistered, or swollen. Stop doxycycline and tell your healthcare provider right away if any of these happen.
Another Infection. Using doxycycline may lead to an infection with other types of germs, such as fungi. Call your healthcare provider if your infection does not improve or gets worse.
Increased Pressure Around the Brain. Doxycycline can increase the pressure around the brain, a serious condition called pseudotumor cerebri or intracranial hypertension. Stop taking doxycycline and call your healthcare provider right away if you experience any of the following symptoms.
- Dizziness
- Nausea and vomiting
- Severe headache
- Vision changes
Permanent Teeth Discoloration. Doxycycline can cause a permanent change in tooth color to yellow, gray, or brown. It may also affect growth of tooth enamel (also called enamel hypoplasia). These side effects can happen during tooth development in the last half of pregnancy and in children up to age 8 years. Tell your healthcare provider if you are or plan to become pregnant. If your child is taking doxycycline and is less than 8 years old, call your healthcare provider right away.
Blood Disorders. Doxycycline can cause blood disorders such as hemolytic anemia, low platelet levels (thrombocytopenia), low neutrophil levels (neutropenia), and low eosinophil levels (eosinophilia). Stop using doxycycline and get help right away if you have any of the following symptoms of blood disorders.
- Fever
- Shortness of breath
- Pale or yellowish skin
- Easy bruising or bleeding
- Frequent infection
- Unusual weakness or tiredness
- Dizziness, lightheadedness, or feeling like you are about to pass out
- Headache
- Fast or abnormal heartbeat
