Augmentin for Sinus Infection: Dosage and Side Effects

woman holding her nose because sinus pain
Medically reviewed by Dr. Ola Tarabzuni

Key Takeaways

  • Augmentin is a combination of two antibiotics, amoxicillin and clavulanate, and is used to treat bacterial sinus infections. It works by preventing the spread of bacteria and weakening their structural support and protection.
  • Augmentin is effective against bacteria that are resistant to amoxicillin alone due to the presence of clavulanate, which inhibits bacterial enzymes that can inactivate amoxicillin.
  • The dosage of Augmentin varies depending on the severity of the infection and is usually taken for 5-10 days. It is important to complete the full course of antibiotics to ensure all the bacteria are eradicated. Common side effects of Augmentin include nausea, diarrhea, vomiting, and skin rashes.


The percentage of people affected each year by chronic sinus infections alone is 12% adults and 10% children in the United States. Moreover, a person suffering from seasonal allergies is more prone to developing sinus infections. This infection can cause symptoms like runny nose, sore throat, or facial pressure. The cause of these sinus infections is mostly viral but can be bacterial in some cases. In case of bacterial infection, your healthcare provider can recommend antibiotics like Augmentin (amoxicillin/clavulanate).

This blog explores how Augmentin works for the treatment of sinus infections.

What is Augmentin?

Augmentin is targeted against bacterial sinusitis and is a combination of two antibiotics including amoxicillin and clavulanate. Both of these medicines work in collaboration with each other to kill the infection-causing bacteria. It is an FDA-approved medicine that not only targets sinus infection but other infections too. 

There are different formulations of this medicine available from oral suspension, chewable tablets, and regular to extended-release tablets. Each is prescribed as per dosage and strength requirements and all are low-cost generics. Augmentin is better than amoxicillin alone because it can work against those bacteria which are resistant to amoxicillin.

How do I know if my sinusitis is viral or bacterial? Ask an Online Doctor

How Does Augmentin Work for Sinus Infections?

For sinus infections, the first line of action is to identify the cause. If the cause is bacterial and not viral then antibiotics are recommended. Each antibiotic works against certain types of bacteria and the mode of action is in accordance with the bacterial mode of action. In the case of sinusitis, the bacteria spread by spreading the fluid or mucus. Therefore, the antibiotic works by creating a cell wall to prevent the bacteria from spreading and weaken its structural support and protection. That’s how the bacteria die after being isolated and not being able to access the resources it needs for its spread and growth. 

Some antibiotics like amoxicillin work by absorbing in the body and therefore, creating cell walls to contain the bacterial infection. However, some bacteria protect themselves against these medicines as they contain an additional enzyme called beta-lactamases. These bacterial proteins inactivate medicines like amoxicillin and gain resistance.

Therefore, to make amoxicillin work against those bacteria, a beta-lactamase inhibitor called clavulanate is attached to it in the form of amoxicillin. This inhibitor blocks bacterial beta-lactamases before it can inactivate amoxicillin. That’s how augmentin works for the effective killing of the bacteria treating a broad range of infections. 

What is the Correct Dosage for Augmentin?

The dosage for augmentin varies from as low as 125 mg to 875 mg dosage for sinus infection. If prescribed every 8 hours or three times a day, it would be 125 mg per dose with a total of 500 mg a day or 875mg/125mg taken every 12 hours. This dosage is continued for at least 5-10 days. The deciding factors in children for the dosage include body weight. For better absorption and to prevent any side effects, it is recommended to take during meals. Keep a check on your medicine schedule and make sure to take your medicine each day at the same time for consistent antibacterial activity. 

Read More: Is It Sinus Or Tooth Pain? Causes, Symptoms and Treatment

When doesn’t Augmentin work for sinus infection?

Sinuses are very sensitive yet crucial body tissues as our whole breathing system depends upon our sinuses. If the antibiotic course has been completed and still you are unwell then you must consult an ENT specialist for a proper diagnosis. An ENT doctor specializes in ear, nose, and throat and can provide better insight on the overall situation.

What is the most common side effect of Augmentin?

The most common side effects of Augmentin include:

  • Nausea
  • Diarrhea
  • Vomiting
  • Skin rashes

Other less common side effects include gassiness, abdominal discomfort, and headaches, skin rash, indigestion, difficulty sleeping, oral thrush, itching, dry mouth, seizures, or even jaundice. 

Does Augmentin interact with anything?

Augmentin can react with certain materials and initiate a reaction. For example, certain medicines react with Augmentin due to their bioactive ingredients or due to underlying medical conditions. Therefore, it is advised to always consult your provider before taking any antibiotic.

Here are some of the following medicines that interact with augmentin and should be avoided taking together: 

  • Doxycycline
  • Bupropion
  • Warfarin
  • Chloroquine
  • Amoxicillin
  • Vitamin D3
  • Exenatide
  • Magnesium citrate
  • Tramadol
  • Methotrexate

Some medical conditions that can interact with augmentin include: 

  • Colitis
  • Hepatotoxicity
  • Hemodialysis
  • Mononucleosis
  • Renal Dysfunction
Will Augmentin clear my sinuses? See an Online Doctor

What are the best antibiotics for a sinus infection?

For sinus infections, the most effective antibiotics that doctors recommend include amoxicillin alone or augmentin (amoxicillin/potassium clavulanate). For sinus infections, doxycycline, levofloxacin, or moxifloxacin can be a great alternative for those with penicillin allergies. Whichever antibiotic is prescribed to you, the doctor would advise you to complete the course by taking the medicine for at least 5-10 days. 

Why is it important to complete the Antibiotic Course?

As per your symptoms and the stage of infection, your provider prescribes you the appropriate dosage of the antibiotic. That dose is enough to first kill the weaker bacteria, then comes the mid-strength bacteria. Once those are killed, the person already feels better in 3-4 days and often discontinues the medicine. What happens next is the most powerful bacteria is still in your body and it makes its move when all the other weaklings are deleted. Therefore, taking the medicine at the right time, in the right dosage, and until the course ends is very crucial for fully nullifying all the bacteria from the body. For example, in the case of augmentin or amox-clav 875-125 mg for sinus infection is the recommended range which works in the span of 5-10 days for effective results.

When to Consult a Doctor

Recurrent infection, pain in the nasal cavity, and persistent symptoms for over ten days indicate chronic illness. Therefore, immediately seek medical advice if you develop any of such symptoms. It’s either due to an allergic reaction or a chronic infection like sinusitis.

FAQs About Augmentin for Sinus Infection

How quickly does Augmentin work for sinus infection?

Augmentin works for sinus infection by blocking the spread of bacteria causing the infection. However, it works only in acute cases and the person starts recovering in 3-4 days.

Is Augmentin better than amoxicillin for sinus infection?

Yes, augmentin is better than amoxicillin as it contains an additional protein inhibitor called beta-lactamase inhibitor. Some bacteria contain beta-lactamase enzyme which can inactivate amoxicillin developing resistance against the medicine. Therefore, augmentation provides an additional layer of protection to avoid the inactivity of the bactericidal effect of amoxicillin. However, your doctor will prescribe amoxicillin in certain conditions where there is a chance of resistant bacteria i.e., to adults older than 65 or in case of severe infection.

What is the best sinus medicine over the counter?

For acute sinus infections, certain over-the-counter medicines can be effective in relieving the pain and easing the symptoms. For example:
Pain Killers: Ibuprofen and acetaminophen. 
Decongestants: Some common decongestants include Sudafed, Mucinex, and Benadryl.

How do I know if I need antibiotics for a sinus infection?

Antibiotics are prescription-only medicines which means your provider will prescribe you antibiotics after examining your symptoms. Therefore, in the case of a sinus infection, if your symptoms are of bacterial infection and are not getting better from OTC medicines in over 10 days then it might be a bacterial infection. Additionally, if there is pus in your sinus cavities then it is a visible sign of bacterial infection and even chronic sinusitis infection.

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