Single-Dose Doxycycline After a Tick Bite

A pharmacist-run clinic prescribing doxycycline for tick bite prophylaxis was described in a recent article by Portman, “Implementing a pharmacist-run Lyme disease postexposure prophylaxis clinic augmented by academic detailing within the Veterans Health Administration.”¹

Programs allowing pharmacists to prescribe doxycycline for tick bite prophylaxis may improve access to care after a tick bite. However, questions remain about whether a single dose of doxycycline is sufficient to prevent Lyme disease.

In April 2018, VA Butler Healthcare in Pennsylvania opened a pharmacist-run Lyme disease postexposure prophylaxis (PEP) clinic known as the PharmLD clinic. At the center, clinical pharmacy specialists were allowed to prescribe doxycycline following a tick bite.

The study primarily examined how a pharmacist-run clinic could manage patients after tick exposure and reduce physician visits. It did not determine whether prophylaxis with doxycycline prevented Lyme disease.

According to the retrospective review, 40 patients were referred to the PharmLD clinic. Each visit included academic detailing, which took approximately 27 minutes per patient.

• 18 individuals (45%) were prescribed a single 200 mg dose of doxycycline for postexposure prophylaxis following a tick bite;
• 12 individuals (30%) received education only;
• 10 patients (25%) were referred to their primary care physician for further evaluation.

The pharmacist-run clinic was able to reduce the number of physician visits, but it was not able to determine treatment outcomes for the patients.

ILADS Position on a Single 200 mg Dose of Doxycycline for a Tick Bite

The ILADS guidelines concluded that a single 200 mg dose of doxycycline might prevent the development of an erythema migrans rash. However, the guidelines found no evidence that a single dose prevents other manifestations of Lyme disease including Lyme carditis, Lyme arthritis, and neurologic Lyme disease.

The ILADS guidelines also raised concern that a single 200 mg dose of doxycycline might suppress early infection and potentially prevent the development of a positive blood test.

[bctt tweet=”A single dose of doxycycline for a tick bite might not prevent Lyme disease.” username=”DrDanielCameron”]

The ILADS guideline authors recommend shared medical decision-making when evaluating patients after a tick bite.

“The preferred regimen is 100–200 mg of doxycycline twice daily for 20 days,” wrote the authors. They added, “Some patients will value avoiding unnecessary antibiotics and prefer not to treat a tick bite prophylactically. Hence, treatment risks, benefits, and options should be discussed with the patient in the context of shared medical decision-making.”²

While pharmacist-run clinics may improve access to care after tick bites, the effectiveness of a single 200 mg dose of doxycycline in preventing Lyme disease beyond the rash remains uncertain.

This discussion also highlights why Lyme disease management often raises difficult questions about diagnosis, prevention, and treatment decisions, themes explored further in Why Lyme Disease Tests the Limits of Medicine.

Patients evaluating treatment options after a tick bite may also benefit from understanding the broader discussion of post-exposure prophylaxis decisions after a tick bite.

Editor’s note: I am one of the authors of the ILADS guidelines and an advocate for shared medical decision-making. I do not find that the current research supports using a single dose of doxycycline as reliable treatment following a tick bite.

Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

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