Side Effects of Doxycycline – The Main Lyme Disease Antibiotic

by lmatthews on August 18, 2014

doxycycline side effects lyme disease antibioticDoxycycline is a key antibiotic used to treat Lyme disease but a recent reduction in the number of manufacturers of this drug has led to increasing costs.

The side effects of doxycycline tend to be lower than with many other antibiotics, and doxycyline is considered the most effective treatment for most cases of Lyme disease, meaning that many people are now being priced out of getting safe and effective Lyme disease treatment.


Doxycycline is also used to prevent malaria and to treat a number of other bacterial infections and acne rosacea, which is why a relative shortage of the antibiotic occurred last year when three producers of the drug stopped manufacturing doxycycline. Despite production having now stabilised the remaining manufacturers have kept prices high, forcing many people to use antibiotics that are less effective, requiring that people take them for longer and incur higher risk of side effects.

Sold as Monodox, Vibra-Tabs, and Vibramycin, doxycycline is a tetracycline antibiotic that works by stopping the growth of bacteria. Doxycycline does not work for viral infections and misuse of the medication can lead to a decrease in its effectiveness over time (i.e. bacteria become resistant to the drug). It is important that anyone prescribed doxycyline take the full course of the medication so as to successfully eradicate infection and reduce the need for repeat prescriptions and increased exposure to undesirable side effects.

Adverse reactions to doxycycline can include:

  • Stomach upset, nausea, vomiting and diarrhoea
  • Sunburn (increased photosensitivity)
  • Difficulty swallowing (neck and throat pain)
  • Altered urinary output
  • Increased intracranial pressure (especially in overweight premenopausal women)
  • Persistent, severe headache
  • Vision changes (decreased vision, blindness, double vision, blurred vision)
  • Antibiotic-associated diarrhoea (typically caused by Clostridium difficile overgrowth)
  • Candida overgrowth (oral or vaginal thrush)
  • Allergic reaction (rash, itching and/or swelling, severe dizziness, trouble breathing)

Although mild gastrointestinal symptoms can be fairly common with doxycycline, more severe or sudden symptoms warrant medical attention. Unfortunately, for those with Lyme disease it may be that symptoms of the infection and side effects of the medication actually overlap, making it difficult for a physician to discern the two. Close consultation with the prescribing doctor is important in order to mitigate the risk of severe reaction to doxycycline and to ensure that alternative treatment is prescribed if necessary.

Children tend not to be prescribed doxycycline as it can have the effect of discolouring the teeth, in addition to being more likely to cause other side effects in those under eight. Doxycycline is also not recommended for use during pregnancy as it may have undesirable effects on the developing foetus. As such, women of childbearing age who are taking doxycycline may wish to use additional methods of birth control. Those who are breastfeeding should let their prescribing physician know before using doxycycline as it does pass into breast milk; this is not thought to pose a significant risk to nursing infants however.

A range of medications and drugs can interact with doxycycline so it is important to ensure that these are discussed with a qualified pharmacist or physician to avoid unwanted effects. Some laboratory tests can also be affected by doxycycline, meaning that anyone taking this medication should let the lab know in advance.


In summary, the most common side effects of doxycycline include:

  • Headache (<26%)
  • Common cold (22%)
  • Nausea (<13.4%)
  • Influenza symptoms (11%)
  • Vomiting (8.1%)
  • Toothache (7%)
  • Tooth disorder (6%)
  • Joint pain (6%)
  • Dyspepsia (6%)
  • Diarrhea (up to 6%)
  • Nasopharyngitis (5%)
  • Sore throat (5%)
  • Sinus congestion (5%)
  • Coughing (4%)
  • Sinus headache (<4%)
  • Menstrual cramp (4%)
  • Periodontal abscess (4%)
  • Acid indigestion (4%)
  • Rash (4%)

Less common symptoms, affecting under 4% of those taking doxycycline, include:


  • Bacterial vaginitis (3.3%)
  • Back pain (<3%)
  • Hypertension (3%)
  • Sinusitis (3%)
  • Bronchitis (3%)
  • Anxiety (2%)
  • Vulvovaginal mycotic infection (2%)
  • Nasal congestion (2%)
  • Increased blood pressure (2%)
  • Back ache (2%)
  • Infection (2%)
  • Fungal infection (2%)
  • Influenza (2%)
  • Upper abdominal pain (2%)
  • Abdominal distention (1%)
  • Abdominal pain (1%)
  • Stomach discomfort (1%)
  • Dry mouth (1%)
  • Muscle pain (1%)
  • Pharyngolaryngeal pain (1%)

Anyone taking doxycycline who experiences other effects should contact their pharmacist or doctor for advice. Patients can report side effects of doxycycline directly to the FDA at 1-800-FDA-1088, or to Health Canada at 1-866-234-2345.


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