How to take Amoxicillin for sinus infection?

Amoxicillin for sinus infection
Medically reviewed by Dr. Mandy Liedeman


A person’s regular life might be severely disrupted by sinusitis. It can be challenging to carry out daily tasks when there is excruciating pain and symptoms, including headache, facial pressure, and congestion from infections on or around the sinuses, nose, and face. One common antibiotic in the penicillin family is amoxicillin. Amoxicillin acts against the bacteria, causing your sinus trouble. But following your doctor’s instructions carefully and completing the course of antibiotics is the key. Taking the right amount at the right time is crucial.
The usage of amoxicillin for bacterial sinus infections will be discussed in this article, along with how it functions and what to anticipate when taking it. Continue reading for additional details, including how much amoxicillin is appropriate for a sinus infection.

How Does Amoxicillin Work for a Sinus Infection?

   “ Dry air is one of the biggest causes of sinus infections, especially for those of us who are naturally predisposed to acute or chronic sinusitis,”

Says Dr. Garette Benette, rhinoplasty and sinus surgeon

Amoxicillin works for sinusitis by targeting and killing the bacteria causing the infection. These bacteria can include:

Bacteria that increase in the sinus canals frequently cause sinus infections. A member of the penicillin family of antibiotics, Amoxicillin prevents these bacteria from growing. The drug disrupts the bacterium’s capacity to form cell walls, eventually destroying them. This supports the removal of the infection by your immune system. To eradicate all germs and reduce the chance of recurring infections or developing antibiotic resistance, it’s imperative to take the prescribed dosage and finish the course of antibiotics, even if symptoms improve. 

How to take Amoxicillin for sinus infection?

Your age and kidney health will determine the amoxicillin dosage for sinus infection. For those older than three months who have normal renal function:

Mild infections

Orally administer 45 mg/kg/day in divided doses every 12 hours for children.

Amoxicillin dosage for adult sinus infection may be 500 mg of Amoxicillin every 8 hours or 875 mg every 12 hours for 5 to 7 days.

It is also available as a combination medication, Amoxi-Clav 875 / 125 mg for adults taken twice daily. 

Frustrated by the sinusitis symptoms? Contact a doctor now for relief!

For severe infections

Take 500 mg or 875 mg orally every 8 hours or 12 hours. 


80–90 mg/kg/day, divided into 12 hourly dosages; 2,000 mg maximum/dose.

The primary healthcare practitioner or pediatrician establishes the dosage for children under three months of age based on their weight.

Your child’s primary healthcare practitioner may utilize the adult dose recommendations if your youngster weighs more than 88 pounds. Individuals with impaired kidney function may require different dosages, as stated below:

Severe kidney impairment

Depending on the infection and kidney impairment degree, the dose may vary from 250 to 500 mg every 12 to 24 hours.

Hemodialysis patients

You may receive a dose of 250–500 mg per 24 hours, with an extra dose either before or after your dialysis session. 

Antibiotics may impact your stomach’s natural flora. This may result in diarrhea, nausea, or upset stomach. It may occasionally assist to take amoxicillin with meals if you experience any gastrointestinal issues while taking it.  It would help if you took amoxicillin precisely as directed. You should stick to the treatment regimen that your doctor has prescribed, even if you feel better after a few days.

How long is it to take Amoxicillin for a sinus infection?

Antibiotics for sinus infections can take two to three days to take effect since our sinuses are challenging to access. 

Even if you start to feel better, you must finish the entire course of antibiotics, usually 7 days, which may be extended to 14 days depending on symptom severity on re-evaluation. Should you not complete the whole course of treatment, your body may begin to develop an immunity to those antibiotics. This complicates treatment in the future.

  • Our doctor will consider many aspects, such as your infection’s severity and age while determining the correct Amoxicillin dosage for sinusitis.
  • When treating sinusitis, amoxicillin dosage is typically higher than for other infections, like ear infections.
  • Adults with sinus infections should take 500 mg of amoxicillin thrice daily for seven to fourteen days.
  • If you are facing severe symptoms, your physician can advise you to take it longer or up the dosage.
  • If you miss a dose, take it as soon as you recall, but avoid the following if it’s almost time. Never take two doses to make up for something you missed. 
  • Furthermore, even if your symptoms subside, make sure you take the entire recommended dosage. If the treatment is stopped too soon, the infection may return.
  • The dosage for kids will change based on their weight and age.

What should be avoided with Amoxicillin used for sinus infections?

Knowing what possible adverse effects amoxicillin may cause is essential while using medication to treat sinusitis.

As with any drug, there are some things and activities that should be avoided when taking amoxicillin because they may reduce its effectiveness or raise the possibility of adverse side effects.

  • First of all, consuming alcohol while taking amoxicillin must be avoided since this may decrease the medication’s efficiency.
  • Avoiding grapefruit juice is also advisable, as it may interfere with the medication.
  • Before using amoxicillin, patients with specific medical disorders, such as renal or liver illness, should consult their doctor as they may be more susceptible to adverse effects.
  • Unless your doctor instructs you otherwise, you must refrain from taking medications, vitamins, or supplements while taking amoxicillin.
  • As the prescription may not be suitable for them, individuals who are pregnant or nursing should talk to their doctor about the dosage of amoxicillin and any possible adverse effects.

Are there any side effects associated with taking amoxicillin for sinus infections?

Amoxicillin is a potent and effective antibiotic, but it has significant adverse effects that need to be taken into account.

Additionally, it may result in a few serious allergic responses, such as:

  • Difficulty breathing
  • Swelling of the lips, tongue, face and throat.
  • Skin hives
Worried about the side effects of Amoxicillin? Contact a doctor now!

Are there any contraindications or precautions when taking Amoxicillin for sinus infections?

It may also result in a general precaution; you should never take medication without properly consulting your physician. 

A valid prescription is the only requirement to get Amoxicillin 500 mg Tablets from a pharmacist or medical facility. 

Before using this medication, you should tell your doctor about a few things, including:

  • If you are allergic to medications like erythromycin, telithromycin, cephalosporins, or clarithromycin.
  • Anaphylaxis and Stevens-Johnson syndrome are examples of severe hypersensitivity to amoxicillin, other beta-lactams, or any ingredient in the formulation.
  • If you are suspected or proven to have infectious mononucleosis. When receiving amoxicillin medication, many individuals with infectious mononucleosis experience an erythematous rash.
  • Whether you experience problems with your muscles, liver, heart, or kidneys.
  • If your potassium or magnesium levels are low.
  • Whether the medication causes you to have nausea, diarrhea, or excessive perspiration 
  • Serious allergic responses, whether you are nursing or pregnant.


Before taking this antibiotic, pregnant women should talk to a doctor about the advantages and disadvantages of the medication. 


For nursing mothers, this medication is only advised if required. If a breastfeeding woman uses this medication, the baby should be watched for any adverse effects. Antibiotics found in breast milk often have the potential to alter gut flora in ways unrelated to dosage. Monitor for gastrointestinal issues in babies, such as diarrhea or thrush (WHO 2002).

While the manufacturer advises using caution while giving amoxicillin to nursing patients, when administered at the appropriate dosages, amoxicillin is thought to be compatible with breastfeeding (WHO 2002).


Bacterial growth brought on by antibiotic therapy can result in diarrhea. This can be the result of overdosing; thus, identify a suitable substitute and modify the dosage accordingly. 

Resistance to drug

Taking this medication without any bacterial infection symptoms is not advised at all. Toxic effects could result from unreasonable use of Amoxicillin 500 mg Tablet. 

Driving or operating heavy machinery

Patients taking this medication may experience excessive sleepiness or dizziness. Do not operate heavy machinery after taking Amoxicillin 500 mg Tablet or its equivalents. 

Can I request Amoxicillin for a sinus infection without seeing a doctor?

Requesting or obtaining prescription medications, including Amoxicillin, is not advisable without consulting a healthcare professional. A sinus infection requires an accurate diagnosis, and the appropriate treatment, including antibiotics, should be determined by a licensed medical provider. You can get a prescription for Amoxicillin via telemedicine platforms, which do not require an in-person evaluation with a doctor. 

Consult a healthcare professional immediately if you have a sinus infection. Based on your illness, they will evaluate your symptoms, do any required tests, and recommend the best action. When using medication without the proper counsel, there may be hazards involved, and the desired result may not materialize.

Get a prescription for Amoxicillin for Sinusitis by connecting with a doctor online now.

Consult a doctor 

Consult a doctor for a sinus infection if you have any of the following :

Persistent Symptoms

If your symptoms persist for more than ten days without improvement or worsen after an initial improvement, it’s time to see a doctor.

Severe Symptoms

If you have severe pain, a high fever, or a sinus infection affecting your vision, it’s crucial to seek medical attention promptly.

Recurrent Infections

A doctor can assist in identifying the underlying cause of your symptoms and provide appropriate therapy if you get sinus infections frequently or if they keep coming back.

Concerns about Antibiotics

If you are considering or currently taking antibiotics, it’s essential to consult with a doctor to ensure proper dosage and duration and to address any concerns or potential side effects.

Chronic Sinusitis

If you suspect you have chronic sinusitis (lasting more than 12 weeks), a doctor can help manage the condition and explore potential causes.

Worsening Respiratory Symptoms

If you develop respiratory symptoms such as shortness of breath, chest pain, or persistent cough, consult a doctor promptly.

Consult now if you have any of the above worrisome symptoms.

FAQs about Amoxicillin for sinus infection

Is 5 days of Amoxicillin enough for a sinus infection?

Adults can be treated with antibiotics for five to seven days, which is sufficient and won’t promote bacterial resistance.

Can I stop taking Amoxicillin once my symptoms improve?

Clinical professionals and health authorities have traditionally recommended that patients take antibiotics as directed for the entire prescribed duration, even if their symptoms have subsided, to avoid antibiotic resistance and infection return.

What should I do if my symptoms persist after completing the Amoxicillin course?

They should talk to their doctor if the symptoms persist or are severe. A doctor may extend the course or may prescribe different antibiotics instead.

Can I take over-the-counter medications along with Amoxicillin for sinus infection relief?

You can take over-the-counter medications for sinus infection relief along with Amoxicillin. Standard over-the-counter options include decongestants, pain relievers, and saline nasal sprays. 

Your Doctors Online uses high-quality and trustworthy sources to ensure content accuracy and reliability. We rely on peer-reviewed studies, academic research institutions and medical associations to provide up-to-date and evidence-based information to the users.

  • Wald, Ellen R., Darleen Chiponis, and Jocyline Ledesma-Medina. “Comparative effectiveness of amoxicillin and amoxicillin-clavulanate potassium in acute paranasal sinus infections in children: a double-blind, placebo-controlled trial.” Pediatrics 77.6 (1986): 795-800.
  • Wald, Ellen R., et al. “Treatment of acute maxillary sinusitis in childhood: a comparative study of amoxicillin and cefaclor.” The Journal of pediatrics 104.2 (1984): 297-302.
  • Arrieta, José R., et al. “Moxifloxacin vs amoxicillin/clavulanate in the treatment of acute sinusitis.” American journal of otolaryngology 28.2 (2007): 78-82.
  • Savage, Timothy J., et al. “Treatment Failure and Adverse Events After Amoxicillin-Clavulanate vs Amoxicillin for Pediatric Acute Sinusitis.” JAMA 330.11 (2023): 1064-1073.

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