One Dose of Doxycycline for the Prevention of Lyme Disease: A Review of Clinical Effectiveness and Guidelines [Internet]

Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; 2019 May 21.


Lyme disease affected 2025 Canadians in 2017, making it the most common vector-borne infection in Canada., Immature black-legged ticks – Ixodes scapularis in Eastern and Central Canada or I. pacificus in British Columbia – infected with the bacteria spirochete Borrelia burgdorferi are responsible for transmitting Lyme disease to humans in Canada. Erythema migrans, fever, and arthralgia are the diagnostic triad for Lyme disease.

In Canada, Lyme disease became a nationally reportable disease in 2009 with black-legged ticks confirmed in sections of British Columbia, Manitoba, Ontario, Quebec, New Brunswick and Nova Scotia. However, half of reported Lyme disease cases in Canada were caused by infected ticks encountered during travel to the eastern United States and Europe.

If an infected tick bite is not detected or is left untreated, Lyme disease can progress to neurological, joint, and cardiac involvement. Lyme disease from an infected tick bite can be prevented if the tick is removed within 24 to 36 hours. Prophylaxis might be considered within 72 hours of tick removal if the vector was identified as an immature black-legged tick which remained attached for more than 36 hours and the patient had visited a region where local rates of infection are greater than 20%. If any of these criteria are unclear, clinician judgment and patient preference is used to determine if prophylaxis or watchful waiting is warranted., If any of these criteria are not met, watchful waiting for 30 days has been recommended to monitor the appearance of fever, arthralgia, and rash symptoms.,

For adults, a single dose of doxycycline (200 mg) has been recommended for prophylaxis after tick attachment for prevention of Lyme disease.,,, For children eight years of age and older, a single dose of doxycycline (4 mg/kg up to the adult dosage)., Doxycycline is contraindicated in pregnant or lactating women as well as in young children due to the risk of possible effects on fetus bone formation and permanent tooth staining.

Use of a single dose of doxycycline as prophylaxis for the prevention of Lyme disease after a tick bite is debated for several reasons: the low risk of infection transmission; the contraindication of doxycycline in children younger than eight years of age; and the uncertainty surrounding its clinical effectiveness. Since the risk of infection is low, even in endemic areas, and Lyme disease is readily treatable once symptoms develop, watchful waiting has been employed instead of prophylaxis, particularly in children.,,,

As a tetracycline, doxycycline is contraindicated in children younger than eight years of age due to the risk of permanent tooth staining or enamel hypoplasia.,, However according to research into Rocky Mountain spotted fever, short courses of doxycycline did not cause permanent tooth staining in children younger than ten years of age. Additionally, in a 2018 survey, 82% of parents would consent to a hypothetical trial of doxycycline for children with Lyme disease. This research may make the case for permitting one dose of doxycycline in all age groups to prevent Lyme disease after tick attachment.,,,

The objective of this report is to summarize the evidence regarding the clinical effectiveness of one dose of doxycycline for the prevention of Lyme disease in patients with tick attachment as well as relevant evidence-based guidelines associated with the use of one dose of doxycycline for the prevention of Lyme disease in patients with tick attachment.

Publication types

  • Review

Grant support

Funding: CADTH receives funding from Canada’s federal, provincial, and territorial governments, with the exception of Quebec.