Accidental Single Dose of Doxycycline Instead of Amoxicillin
Taking one dose of doxycycline instead of amoxicillin will not cause harm, and you should simply continue taking your prescribed amoxicillin as directed without any modifications to your treatment plan.
Why This Is Safe
No dangerous drug interaction exists between a single dose of doxycycline and subsequent amoxicillin therapy—these antibiotics work through different mechanisms (doxycycline inhibits protein synthesis while amoxicillin inhibits cell wall synthesis) and do not create toxic combinations 1.
Both antibiotics are commonly used in clinical practice and have overlapping safety profiles, with the most common side effects being gastrointestinal upset (nausea, diarrhea, stomach discomfort) that are generally mild and self-limited 1, 2.
Sequential antibiotic use is medically acceptable—in fact, some treatment protocols intentionally use sequential administration of different antibiotics for specific infections, demonstrating that switching between these drug classes does not cause harm 3.
What to Do Next
Continue your amoxicillin exactly as prescribed starting with your next scheduled dose 4.
Do not skip or double any doses of amoxicillin to "make up" for the doxycycline dose 1.
Monitor for typical antibiotic side effects such as mild gastrointestinal upset, which may occur with either medication but are generally not serious 1, 2.
Important Caveats
If you develop any allergic reaction symptoms (rash, hives, difficulty breathing, swelling of face/lips/tongue), seek immediate medical attention regardless of which antibiotic caused it 1.
Inform your prescribing physician about the medication error at your next visit or contact them if you have concerns, though this single dose substitution does not require emergency intervention 1.
Ensure you're taking the correct medication going forward by checking pill bottles carefully and separating medications physically to prevent future mix-ups 1.