While adverse reactions to doxycycline are uncommon, some patients who take the drug may experience side effects, including headaches, gastrointestinal problems (nausea, vomiting, diarrhea), and dermal photosensitivity (increased skin sensitivity to sunlight). Doxycycline and other antibiotic medications have been known to cause yeast infections, so be on the lookout for symptoms like vaginal discharge, itching, or discomfort.
Seek medical attention right away if you experience any of the following symptoms such while taking doxycycline:
- Blistering, peeling, or loosening of the skin
- Bloating or indigestion
- Chills or fever
- Clay-colored stools or severe constipation
- Cough or sore throat
- Dark urine
- Severe diarrhea, which may also be bloody
- Difficulty with swallowing
- Fast heartbeat
- Hives, rash, welts, itching, puffiness or swelling of the eyelids or around the eyes, face, lips, throat, hands, legs, feet, tongue, or sex organs
- Increased thirst
- Inflammation or pain in joints and muscles
- Loss of appetite or unusual weight loss
- Nausea or vomiting
- Numbness or tingling of the face, hands, or feet
- Pain in the stomach, side, or abdomen, possibly radiating to the back
- Red skin rash or lesions, often with a purple center
- Redness and soreness of the eyes
- Sores, ulcers, or white spots in the mouth or on the lips
- Stomach cramps, pain or tenderness, swollen, painful, or tender lymph glands in the neck, armpit, or groin
- Tightness in the chest
- Trouble breathing
- Unusual tiredness or weakness
- Yellow eyes or skin
This is not a complete list of adverse effects. Call your health care provider if symptoms are persistent or severe.
As with all prescription medication, be sure to inform the prescribing doctor about any medical conditions you have been previously diagnosed with, as well as any medication/ supplements you are currently taking before starting treatment with doxycycline. Doxycycline can interact with other forms of medication and substances, causing potentially serious side effects or life-threatening allergic reactions. Drug interactions can occur with blood thinners such as warfarin, certain retinoids, penicillin, and proton pump inhibitors among others.
Antacids and supplements containing calcium and magnesium can reduce the amount of doxycycline that your body absorbs, so be sure to take doxycycline 1–2 hours before or 1–2 hours after taking antacids or supplements.
The use of doxycycline can cause your skin to become sensitive to sunlight or ultraviolet light, so try to avoid unnecessary exposure to the sun or UV rays and do your best to wear protective clothing, sunglasses, or sunscreen that is SPF 15 or higher. Call your doctor if you notice redness, swelling, or blistering as a result of sun exposure while on doxycycline.
Oral contraceptives (birth control pills) with estrogen can lose effectiveness when combined with tetracycline, so unplanned pregnancy can occur.
In addition, let your doctor know if you are breastfeeding, pregnant or plan on becoming pregnant before starting treatment with this medication.