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Amoxicillin for a Sinus Infection

Sinus infections occur when the lining of the sinus cavity becomes swollen, irritated and inflamed, blocking normal drainage, according to the Mayo Clinic. Due to blockage, mucus builds up within the sinuses and bacteria sets in, leading to an infection. Various drugs are used to treat a sinus infection, such as decongestants, antihistamines and anti-inflammatory pain relievers, but the most common way to kill the bacteria is with antibiotics. The most common antibiotic used for sinus infections is amoxicillin 24.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.


Amoxicillin is in the penicillin category of antibiotics 24. It is considered a narrow-spectrum antibiotic, used for a specific type of bacterium. Amoxicillin works by disrupting the bacterium’s building of its cell wall 24. Once the bacterium grows to a certain level, it bursts and destroys the infection. But amoxicillin may kill other helpful bacteria in the body during the duration of taking this medicine 24.


Most Common Dosage of Amoxicillin for Sinus Infection

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Do not take amoxicillin if you are allergic to penicillin drugs or other antibiotics 24. Talk to your doctor about alternative antibiotic treatments to treat the sinus infection. If you have gastrointestinal issues, heart disease or a liver disease, amoxicillin may not be the right drug for you 24. Amoxicillin may decrease the effectiveness of various types of birth control, so you should take additional precautions if you are avoiding getting pregnant 24. Taking a probiotic supplement in conjunction with the antibiotic will help to maintain good bacteria levels in the gut and throughout the body, preventing diarrhea. Take the entire dose prescribed, even if your symptoms improve; otherwise, you risk the chance of the sinus infection returning.

Side Effects

According to, the common side effects while taking amoxicillin are fever, headache and sore throat 24. More serious, yet less common, side effects include:

  • stomach pain with vomiting
  • vaginal itch
  • severe head pain
  • black or swollen tongue,
  • thrush accompanied by a sore throat


How Long Does it Take for Amoxicilin to Work?

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Amoxicillin may be taken with or without food, as it does not typically affect the stomach 24. The common dose for children is between 200 and 400 mg twice a day for up to 10 days. Children’s amoxicillin comes in liquid form and should be shaken vigorously before given, to ensure the drug is evenly distributed 24. For adults, pills of 500 to 875 mg are prescribed and taken twice daily for up to 10 days.


The overuse of antibiotics may make you immune to amoxicillin 24. If you develop a tolerance to this drug, your doctor may recommend a different classification of antibiotic to treat your sinus infection. Avoid using antibiotics when possible 3. Talk to your doctor about any concerns you may have related to penicillin.