Doxycycline is the most commonly prescribed antibiotic for Lyme disease in adults and children. Most cases, especially those caught early, clear up with a 10 to 14 day course of oral antibiotics. The specific antibiotic and duration depend on how far the infection has progressed and the patient’s age.
First-Line Antibiotics for Early Lyme Disease
For the classic bull’s-eye rash and early symptoms like fatigue, fever, and joint aches, three oral antibiotics are standard options:
- Doxycycline for 10 to 14 days. This is the go-to choice for most adults and children. It has the advantage of also treating other tick-borne infections that sometimes ride along with Lyme.
- Amoxicillin for 14 days. Often chosen for young children or people who can’t take doxycycline.
- Cefuroxime for 14 days. A backup option for people who are allergic to both doxycycline and amoxicillin.
If you can’t tolerate any of those three, azithromycin is sometimes used, but it’s considered less effective. People treated with azithromycin need closer follow-up to make sure the infection actually clears.
Treatment for Children
Children receive the same three antibiotics, with doses adjusted by weight. Doxycycline is dosed at 4.4 mg per kilogram of body weight per day, split into two doses, with a cap of 100 mg per dose. Amoxicillin is dosed at 50 mg per kilogram per day, split into three doses. Cefuroxime is 30 mg per kilogram per day in two doses.
There’s a longstanding concern about doxycycline staining developing teeth in children under 8. For short courses like those used in Lyme disease, many providers still consider it appropriate, but amoxicillin is a common alternative for younger kids. Your child’s provider will weigh the options based on age and any allergies.
When Lyme Disease Has Spread Further
If the infection moves beyond the skin and into the nervous system or heart, treatment gets more intensive. The antibiotics change, and you may need them through an IV rather than by mouth.
Neurologic Lyme Disease
Lyme disease can cause meningitis (inflammation around the brain), facial nerve paralysis, or nerve pain radiating from the spine. For these cases, the Infectious Diseases Society of America recommends either IV antibiotics or oral doxycycline for 14 to 21 days. IV options include ceftriaxone, cefotaxime, or penicillin G. If the infection has reached the brain or spinal cord tissue itself, IV antibiotics are strongly preferred over oral treatment.
Cardiac Lyme Disease
Lyme can interfere with the heart’s electrical signaling, causing an irregular or dangerously slow heartbeat. Patients who need hospitalization for this typically start on IV ceftriaxone and then switch to oral antibiotics once their heart rhythm improves. Total treatment runs 14 to 21 days.
Preventing Lyme After a Tick Bite
A single 200 mg dose of doxycycline can reduce your risk of developing Lyme disease after a tick bite, but it only makes sense in specific circumstances. Five criteria guide the decision:
- The bite happened in an area where ticks commonly carry the Lyme bacterium.
- The tick was removed within the past 72 hours.
- The tick was a blacklegged (Ixodes) tick, the only type that transmits Lyme in the United States. These are small and teardrop-shaped.
- The tick was engorged with blood, meaning it had been feeding long enough to potentially transmit the infection. A flat, unfed tick is unlikely to have passed the bacteria along.
- Doxycycline is safe for you (no allergy, not pregnant or breastfeeding).
For children weighing under 45 kg (about 99 pounds), the preventive dose is 4.4 mg per kilogram. Because the Lyme bacterium takes at least three days to cause infection after a bite, this single dose works best when taken within that 72-hour window. If you can’t identify the tick, preventive treatment can still be considered.
Side Effects of Doxycycline
Since doxycycline is by far the most common prescription for Lyme, its side effects are worth knowing about. The most frequent ones are digestive: nausea, vomiting, diarrhea, and loss of appetite. Taking it with food and a full glass of water helps. Avoid lying down for at least 30 minutes after a dose, since the pill can irritate your esophagus.
Doxycycline makes your skin noticeably more sensitive to sunlight. Sunburns can happen faster and more severely than you’d expect, so sunscreen, sunglasses, and protective clothing matter during treatment. Less commonly, people develop yeast infections, sore throat, or dry mouth.
Serious reactions are rare but include severe headache with blurred or double vision (a sign of increased pressure in the skull), significant skin rashes with peeling or blistering, and difficulty breathing or swallowing. Doxycycline should not be taken during pregnancy because it can harm the developing baby, and breastfeeding mothers are generally advised to avoid it as well.
What to Expect During Treatment
Most people with early Lyme disease start feeling better within a few days of beginning antibiotics, though full recovery can take a few weeks. The rash fades, fevers break, and joint pain gradually eases. Finishing the entire course matters even if symptoms improve quickly, because stopping early risks leaving bacteria behind.
A small percentage of people, roughly 5 to 10%, continue to have fatigue, pain, or cognitive difficulties for weeks to months after completing treatment. This is sometimes called post-treatment Lyme disease syndrome. Longer or repeated courses of antibiotics have not been shown to help with these lingering symptoms, and current guidelines recommend against extended antibiotic therapy beyond the standard course.