One Dose Doxy Does Not Work

Single Dose Doxycycline for Tick Bites

It does not cure or prevent Lyme disease.

If you have a tick bite and are only offered a prescription for 200mg of doxycycline, the most common antibiotic used to treat Lyme and other tick borne diseases, please consider the following information.

The recommendation for one dose of doxycycline for humans after a tick bite is based on the results of one flawed study. This study is highly problematic for a number of reasons.

1.) The study based its end point on the appearence of a Lyme rash (EM or bulls-eye rash) after receiving the one dose of doxycycline. The prevention of an EM rash at the bite site is not an appropriate indicator that a person does not have Lyme disease.

2.) The study was short-lived. Lyme disease symptoms can wax and wane over months or even years. The study only followed the participants for six weeks, so the authors were unable to determine if anyone went on to develop a rash or symptoms.

3.) The risk of acquiring an additional tick borne disease after a bite is growing. Spotted fevers, Ehrlichia, Anaplasma, Bartonella and Babesia are some of the better known co-infections that can be transmitted at the same time as Lyme disease. One dose of doxycycline has not been tested as an affective deterent to acquiring any of these potentially life-threatening infections.

4.) One dose of doxycycline may negatively affect future blood tests by stifling the immune system so it doesn't produce antibodies at a measurable level. Lyme tests have been shown to miss 74.9% of those who are infected without the one dose of doxycycline interference, and taking antibiotics for any reason has been shown to be a risk factor that can negatively affect Lyme test results.

In another study the following year (2002), Development of erythema migrans in spite of treatment with antibiotics after a tick bite, regarding the one dose of doxycycline theory, the authors disagreed with the original study and stated...

QUOTE- "...the seven patients presented demonstrate that antibiotic prophylaxis [with 200 mg of doxycycline] for Lyme borreliosis after a tick bite... is not entirely effective." Source

The International Lyme and Associated Diseases Society (ILADS) protocol for treating a tick bite is to not recommend the one dose of doxycycline and instead- "Recommends prompt prophylaxis with doxycycline 100 -200 mg twice daily for a minimum of 20 days for all Ixodes tick bites in which there is evidence of tick feeding..." Source

In another study on mice in 2012, the Centers for Disease Control (CDC) determined...

QUOTE- "When treatment was delayed until 24 h after tick removal, only 47% of mice were protected; prophylactic treatment was totally ineffective when delivered ≥2 days after tick removal." Source

People who have developed chronic Lyme disease will also often say to take the full course of antibiotics outlined in Evidence assessments and guideline recommendations in Lyme disease: the clinical management of known tick bites, erythema migrans rashes and persistent disease by Dr. Daniel Cameron, et. al. to help prevent you from becoming chronically ill, disabled, or worse.

After a tick bite, untreated, or after taking one dose of doxycycline or the full course, if you develop symptoms contact your health-care provider immediately so any Lyme and/or other tick borne diseases you may have contracted can be more effectively treated.

A printable, one page document with the treatment protocols for treating adults and children for a tick bite can be found here. There is also a document to print and take to your doctor's office with you if you have any symptoms or a rash after a tick bite. Get it Right- Treat The Bite!

Additional Information

QUOTE- "The IDSA guidelines recommend the single dose doxycycline as a prophylactic for Lyme disease. ILADS’ preferred prophylactic treatment for a person in an endemic area who discovers a feeding blacklegged (deer) tick is “100–200 mg of doxycycline, twice daily for 20 days” and they note “Other treatment options may be appropriate on an individualized basis."

Evidence assessments and guideline recommendations in Lyme disease: the clinical management of known tick bites, erythema migrans rashes and persistent disease

Daniel J Cameron, Lorraine B Johnson & Elizabeth L Maloney

Expert Review of Anti-infective Therapy, Volume 12, 2014 - Issue 9

Published Online: 30 Jul 2014

Last Update- February 2019

Lucy Barnes