Sinus infection or sinusitis is a condition when the mucous membranes (lining the sinuses and the nasal passage) are irritated and inflamed due to bacterial, viral or fungal infection. The sinuses are air-filled connected cavities in the skull that produce a thin layer of mucus and drain into the nose.

The function of these connected systems of hollow cavities is not very clear, but experts believe that they are meant for humidifying the air and enhancing our voices.
A sinus infection may also occur when the draining mucus is blocked due to a deviated septum, nasal polyps, allergic rhinitis or common cold. Most often, sinus infection is mistaken for a common cold. Sometimes, it may be really difficult to differentiate between a sinus infection and the common cold.
Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, Staphylococcus aureus, and Moraxella catarrhalis are the five most common variants of bacteria that trigger sinusitis.

Streptococcal bacteria in sinuses. 3D illustration.
Amoxicillin is the first choice when it comes to treating a sinus infection as it is one of those drugs that is quite effective against combating all the aforementioned strains. It also comes with fewer side effects, when compared to other antibiotic drugs.
Use of Amoxicillin in Sinus Infection
Amoxicillin is a very common antibiotic to treat a wide range of bacterial infections. Amoxicillin is particularly useful against certain alpha and beta-hemolytic strains of bacteria (like Streptococcus pneumonia and beta-lactamase-producing strains of Haemophilus influenza or Moraxella catarrhalis) that infect sinus cavities, ear, and throat.
Amoxicillin should always be taken when your doctor prescribes it to treat your medical conditions. Amoxicillin is available in different combinations and your doctor will decide what combination or dosage is suitable for you.
For example, Amoxicillin is not a good antibiotic if you are allergic to cephalosporin or penicillin group of medicines. In fact, allergic reactions can be very severe and require immediate medical attention.

Amoxicillin Dosage for Sinus Infection
According to the official literature, the dosage of amoxicillin for adults can range from 250 mg. to 1 gm three times a day, depending on the severity of the infection. For children, 20 mg. per kg. body weight can be given in three divided doses.
In the case of mild to moderate infections, your doctor may prescribe 250 mg. three times a day or 500 mg. two times a day. For severe sinus infections, 500 mg three times a day or 875 mg two times a day can be recommended by the doctors.
For children, 20 mg. / kg. body weight three times a day or 25 mg. / kg. body weight two times a day is normally recommended by the doctors. In severe infections, the doctors may prescribe 40 mg. / kg. body weight three times a day or 45 mg. / kg. body weight two times a day.
Amoxicillin dosage depends on the age, body mass, and health condition of the patients. Your doctor may change the dose and duration of the treatment by monitoring certain health parameters during the treatment.
So, always take amoxicillin under the recommendation and supervision of a credible practitioner. You should never take amoxicillin or any other medicine on your own because it may affect your health condition, particularly if you have any liver or kidney issues.
Side Effects of Using Amoxicillin for Sinusitis
Every drug comes with its own set of side effects. And, this antibiotic also has. Some of the most common side effects of using this drug are:
- Bloating
- Diarrhea
- Nauseating sensation
- Upset stomach
- Metallic taste in the mouth
- Tiredness
Prolonged use of this medication could cause dark urine, abdominal pain, and skin rashes/hives. If you experience any such condition, please visit the doctor.
Contraindications for Using Amoxicillin
This antibiotic is not the right choice of antibiotic to treat your troubling sinuses if you have one or more of the following conditions:
- Mononucleosis
- Live problems
- Renal troubles
- Bacteria-related colitis
- Allergic to antibiotics like penicillin
Is Amoxicillin Good for a Sinus Infection?
The answer to this question depends on your medical condition. Sinus infection is caused by several factors like allergic rhinitis, nasal polyps, deviated septum, and fungal, bacterial ot viral infections. Unfortunately, amoxicillin is not very effective against viral or fungal infections.
Most of the sinus issues are caused by viral and fungal pathogen. Bacterial growth may occur as a secondary infection. In such cases, amoxicillin can treat only a bacterial infection.
If you are suffering from nasal polyps, deviated septum or other underlying conditions that induce sinus infection, amoxicillin may provide only temporary or no relief at all.

Proper treatment of sinus infection involves effective management of underlying conditions that cause allergic rhinitis or block the paranasal drains. Your doctor may prescribe certain steroid sprays or recommend turbinectomy, balloon sinusplasty or other surgical techniques to take care of the underlying conditions that cause frequent sinus infections.
Is Amoxicillin Necessary for Sinus Infection?
According to a study conducted by the Washington University School of Medicine in St. Louis, Missouri, USA, it was pointed out that taking amoxicillin for sinus infection does not help in quicker recovery.
The study that appeared in the JAMA on 15 February 2012 also suggests that the drug does not help in alleviating the symptoms associated with the infection.
However, more studies are required to confirm this condition.
According to doctors, it is advisable to wait for at least 10 days before opting for a diagnosis. A bacterial sinusitis is often accompanied by a fever that does not fall below 102 degrees and an intense facial pain.
If you experience any of the abovementioned symptoms, then please do visit the doctor for an antibiotic prescription. Till then, stay away from using over-the-counter antihistamines and nasal decongestants.
Augmentin For Sinus Infection
This drug contains a mixture of amoxicillin and clavulanate potassium.
Augmentin is used to treat several different infections, such as skin infections, ear infections, urinary tract infections and sinusitis.
How to use Augmentin
If you are allergic to clavulanate potassium or amoxicillin, or if you have ever had liver problems after taking this medication, then do not use Augmentin.
Consult with your doctor if you have any of the following conditions:
- Liver disease
- Mononucleosis;
- Kidney disease;
- History of jaundice or hepatitis
- If you are allergic to a cephalosporin antibiotic, for example cephalexin (Keflex), cefdinir (Omnicef), cefuroxime (Ceftin) and cefprozil (Cefzil).
Augmentin can cause diarrhea, which may be a symptom of a new infection. So, if you have diarrhea that has blood in it or is watery, call your doctor and stop taking Augmentin
Clavulanate potassium and Amoxicillin can pass into breast milk and may also harm a nursing baby. Therefore, if you are breast-feeding a baby, do not use this drug without the consultation of your doctor
Good info.
very good info.
I am 72 years old. I have had symptoms of sinusitis for over 60 years with no let-up. My initial symptoms were complaints of constant breath from others. I had no clue of sinus implications. Through the years that problem has become manifest a hundred fold. As a result, I began to confine myself to a rather reclusive lifestyle. In 1984 I had my first sinus operation at the old ‘Philadelphia General Hospital’. That operation got severely infected. I had my second sinus operation in 2012 which did not alter my symptoms at all. My overall symptoms have become unbelievably overwhelming. The constant sinus drainage originating in my upper sinuses causes a peppery taste and feel on the back of my tongue and throat, and has become increasingly offensive smelling. My condition has became too distractive for me to visit doctor’s waiting rooms. I don’t know what to do! Please advise me if you can. . .
I do not have health insurance. Just so you know “Fishmox Forte” Is the exact same as human consumption Amoxicillin. It is sold at any pet store (in the fish department about $25 for 500mg for 100 pills). Bring a pill into a pharmacist they will tell you that it is same exact pill. Be sure to get Thomas Labs brand. It is pure and the best. Do not take it if you are allergic to Amoxicillin! I keep it on hand for emergencies.
There may be a simple fix for your issues with foul breath. Buy and take Acidophilus pills or lozenges. They are available over the counter and work wonders
I have sinusitis and am taking amolicillin and clavulanate potassium.How long till I will no longer be contagious