Doxycycline is a tetracycline antibiotic that doctors use to treat gram-positive and gram-negative bacterial infections. Using doxycycline to treat Lyme disease is common practice.

Doxycycline is an oral medication that a doctor prescribes in the form of a tablet, capsule, delayed-release tablet, or suspension. It is also called doxycycline hyclate or doxycycline monohydrate.

A person can take the tablet with food or milk to prevent stomach upset, and a person should take delayed-release tablets whole.

It is currently one of the antibiotics recommended for the treatment of Lyme disease by the Infectious Diseases Society of America in its Clinical Practice Guidelines for the Treatment of Lyme Disease.

This article will examine how doxycycline can treat Lyme disease.

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The initial treatment duration of doxycycline for early-stage Lyme disease may last 10–14 days.

The National Institute of Allergy and Infectious Diseases indicates that this short course of antibiotics is enough to cure the majority of cases.

However, for people experiencing complicated Lyme disease or late stage Lyme disease, doxycycline treatment may extend for longer.

Erythema migrans rash

Doctors will prescribe doxycycline in the following dosages to treat the rash associated with Lyme disease:

AgeDoseDuration
adults100 milligrams (mg), twice per day10–14 days
children4.4 milligrams per kilogram (mg/kg) per day, divided into 2 doses10–14 days

Neurologic Lyme disease

Doctors will prescribe doxycycline in the following dosages to treat neurologic symptoms associated with Lyme disease:

ReasonAgeDoseDuration
facial palsyadults100 mg, twice per day14–21 days
children4.4 mg/kg per day, divided into 2 doses14–21 days
Lyme meningitis or radiculoneuritisadults200 mg per day, in 1 or 2 doses14–21 days
children4.4 mg/kg per day, in 1 or 2 doses14–21 days

Lyme carditis

Doctors will prescribe doxycycline in the following doses to treat Lyme carditis:

ReasonAgeDoseDuration
mild heart blockadults100 mg, twice per day14–21 days
children4.4 mg/kg per day, in two doses14–21 days

Doctors do not prescribe doxycycline to treat severe heart block. Instead, they will prescribe ceftriaxone.

Lyme arthritis

Doctors will prescribe doxycycline in the following doses to treat Lyme arthritis:

AgeDoseDuration
adults100 mg, twice per day28 days
children over 8 years old4.4 mg/kg per day in 2 doses28 days

Doctors do not prescribe doxycycline to children under the age of 8 years. Instead, they will prescribe amoxicillin or cefuroxime.

One-time dosing

If a person has been bitten by a tick in a region of the country where Lyme disease is prevalent, a healthcare professional may choose to prescribe a single dose of doxycycline as a preventive measure.

The Centers for Disease Control and Prevention (CDC) note that preventive single dosing for adults is 200 mg. For children weighing under 45 kg, single dosing is 4.4 mg/kg.

The efficacy of doxycycline for Lyme disease treatment remains controversial, despite current diagnostic protocols advocating its use.

In 2019, a review published in the journalCanadian Agency for Drugs and Technologies in Health evaluated the efficacy of one-dose doxycycline for Lyme disease prevention.

Researchers concluded that proactive doxycycline was effective for the prevention of Lyme disease in patients with tick attachment. However, small sample sizes, insufficient follow-ups, and other validity issues were apparent in the studies reviewed.

In 2021, a similar systematic review and meta-analysis from the journal BMC Infectious Diseases investigated the proactive use of antibiotics against Lyme disease.

This review also found merit for the use of single-dose doxycycline, but the authors noted that they saw no evidence of any effectiveness in a 10-day course of treatment or in the use of topical antibiotic therapy.

Other research offers similar concerns about doxycycline for effective Lyme disease treatment.

In the Microbiology Spectrum Journal, a meta-analysis involving 40 years of data on antibiotic use in Lyme disease found that amoxicillin, azithromycin, ceftriaxone, and cefotaxime were effective treatment options, but the authors observed no significant efficacy or safety for doxycycline.

A 2022 review from Frontiers in Public Health states that doxycycline, due to being highly protein-bound in circulation, is unlikely to sufficiently diffuse into the tissues affected by Lyme disease bacteria, and that tetracycline appears in clinical observation to be a superior antibiotic choice.

The same review indicates there may be grounds to use higher doses of doxycycline for Lyme disease, 300–400 mg per day, based on success reported in numerous clinical settings.

Doxycycline use may cause side effects such as:

In some cases, more serious side effects may develop, including:

These side effects are considered serious and should be evaluated by a doctor as soon as possible.

Some side effects, such as bloody stools and abdominal cramping, may occur up to 2 months after a person stops taking doxycycline.

In rare cases, doxycycline has been associated with severe adverse reactions, such as:

  • Stevens-Johnson syndrome — a rare condition affecting the skin and mucous membranes that develops as a reaction to medication
  • anaphylaxis
  • intracranial hypertension — a buildup of pressure around the brain
  • anemia
  • photosensitivity — a sensitivity to sunlight

Potential drug interactions may occur between doxycycline and the following:

  • anticoagulants
  • penicillin
  • antacids
  • iron preparations
  • oral contraceptives
  • barbiturates
  • anti-epileptics
  • Penthrane

People may wish to avoid doxycycline if they:

  • have experienced hypersensitivity to tetracycline use in the past
  • are under 8 years of age
  • are pregnant or nursing
  • have a history of yeast infections

There are contraindications for its use in certain conditions, such as:

  • lupus
  • intracranial hypertension
  • Clostridioides difficile-associated diarrhea (CDAD)
  • liver disease due to rare fatal hepatotoxicity
  • myasthenia gravis — a long-term condition that results in muscle weakness
  • porphyria — a group of liver conditions

Emerging evidence suggests there may be superior choices to doxycycline for Lyme disease treatment beyond single-dose preventatives.

However, doxycycline can treat other tick-borne diseases. For example, it can also treat ehrlichiosis, spotted fever, and anaplasmosis.

If a person lives in an area where more than one of these diseases is prevalent, prescribing doxycycline allows a broad spectrum of protection.

Doxycycline is part of the recommended protocol for tick-bite prophylactic treatment in the prevention of Lyme disease and appears to be proven effective for this purpose.

Doxycycline is an antibiotic commonly prescribed for the prevention and treatment of Lyme disease.

After short-term use, typically 10–14 days, most people make a full recovery on a doxycycline regimen.

Despite decades of use, the efficacy of doxycycline in Lyme disease treatment is controversial and still being evaluated. Current research trends support doxycycline as a preventive single-dose option for Lyme disease. However, other antibiotics may hold more promise as long-term treatment options.