Metronidazole and Sinus Infection

Will Metronidazole Treat Sinus Infection?

By Nicholas White

Sinus infections are widespread among children and adults. Such conditions most often develop against the background of respiratory disease, such as influenzae. If left untreated, the inflammatory process can spread from the sinus to nearby tissues and cause a serious, life-threatening complication. Therefore, timely diagnosis and proper treatment are very important. Will Metronidazole Treat Sinus Infection?

What is a Sinus Infection

Sinusitis is an inflammatory disease of the mucous membranes of the paranasal sinuses: maxillary, frontal, ethmoid, and sphenoid. Sinuses are cavities in the bones of the skull that connect to the nasal passages and perform protective, pneumatic, and partially speech functions.

Depending on the location of the inflammatory process, the following types of sinusitis are distinguished:

  1. Sinusitis (maxillary sinus);
  2. Frontitis (frontal sinus);
  3. Ethmoiditis (ethmoid sinus);
  4. Sphenoiditis (sphenoid sinus).

Sinus infections can be unilateral or bilateral. If the inflammatory process affects the mucous membrane of all sinuses at once, the pathology is called pansinusitis.


The key reason for the appearance and development of sinusitis is the accumulation of excessive mucus in the sinuses and impaired drainage, which causes inflammation. Here are the reasons for this condition:

  • Fungal infection;
  • Immunodeficiency;
  • Allergic reactions;
  • Chemical poisoning;
  • Hypothermia;
  • Deformation of intranasal structures (structural anomalies or deviated septum);
  • Nasal polyps;
  • Staying in dusty rooms;
  • Bacterial or viral infection.

Symptoms can vary depending on the cause. But in general, there are a number of typical symptoms that accompany the sinus infection. The paragraph below provides more information on this.


According to the World Medical Association, acute rhinosinusitis is usually characterized by the following symptoms:

  • Nasal congestion and impaired smell;
  • Frequent sneezing;
  • Mucous, mucopurulent, or purulent nasal discharge;
  • Pain in the throat, teeth, ears;
  • Pain over the affected sinus, aggravated by tilting the head forward and down;
  • Tension in the eye sockets, nasal bridge, cheekbones, above the eyes (depending on which sinus is affected by the inflammatory process);
  • Cough (occurs due to postnasal drip);
  • Headache;
  • Increased body temperature;
  • Decreased performance, fatigue, loss of appetite, and general deterioration in well-being.

In the chronic form, the symptoms are less pronounced, the disease lasts a long time, with frequent relapses.

Common Treatments for Sinus Infections

Modern otorhinolaryngology distinguishes three methods in the treatment of sinusitis: conservative therapy, physiotherapy, and surgery.

The conservative treatment plan includes taking different groups of medications:

  • Antihistamines;
  • Systemic antibiotics;
  • Bacterial lysates;
  • Antiseptics;
  • Vasoconstrictor nasal sprays and drops, etc.

To remove excess mucus from the sinuses, doctors often use a YAMIK sinus catheter. This is a non-puncture method of treating acute sinusitis by creating controlled pressure in the nasal cavity and paranasal sinuses.

Physiotherapy includes magnetic therapy, inhalation with a nebulizer, acupuncture, intranasal blockade, electrophoresis, UHF, etc.
If the first two methods are ineffective, patients are recommended to undergo head neck surgery. The most common treatments in this case are polysinusotomy, maxillary sinus puncture, balloon sinuplasty, etc.

Antibiotics for Sinus Infections

Clinical practice shows that systemic antibiotic therapy is a first-line treatment for bacterial infections. Its goal is to eradicate the infection and restore sterility of the sinus. The choice of drug is usually based on the predominance of certain pathogens, their resistance in the region, and the severity of the patient’s condition.

The most effective are penicillin antibiotics (Amoxiclav, Flemoclav Solutab, Amoxicillin Clavulanate potassium, Augmentin), cephalosporins (Cefazolin, Ceftriaxone, Cefuroxime), macrolides (Sumamed, Macropen, Clarithromycin), nitroimidazole derivatives (Omoconazole, Fenticonazole, Bifonazole, Metronidazole), etc.

Local therapy involves the use of nasal sprays such as Isofra (framycetin) and Polydexa (the composition includes the antibiotics neomycin and polymyxin, the corticosteroid dexamethasone, and the vasoconstrictor component phenylephrine). In the case of catarrhal sinusitis, they can penetrate through the anastomoses of the paranasal sinuses and directly contact the pathogen.

What is Metronidazole

Metronidazole for sinus infection is prescribed quite often today. It is a derivative of nitroimidazole with antiprozoic and antibacterial effects, active against Porphyromonas gingivalis, Prevotella intermedia, Prevotella denticola, Fusobacterium fusiformis, Moraxella catarrhalis, Wolinella recta, Eikenella corrodens, Borrelia vincenti, Bacteroides melaninogenicus, Streptococcus spp, Selenomonas spp, etc.

Will Metronidazole treat sinus infection? It treats sinusitis and many other diseases caused by the activity of anaerobic bacteria and protozoa. Common Metronidazole uses include:

  • CNS infections (meningitis, brain abscess);
  • Lung and pleural infections (necrotizing pneumoniae, aspiration pneumonia, lung abscess);
  • Endocarditis;
  • Infections of the gastrointestinal tract and abdominal cavity (peritonitis, liver abscess, purulent lesions of the abdominal or pelvic cavity);
  • Gynecological infections (endometritis, puerperal fever);
  • Infections of ENT organs and oral cavity (rhinosinusitis);
  • Bone and joint infections (osteomyelitis);
  • Gas gangrene;
  • Septicemia with thrombophlebitis.

How Metronidazole Works

Antibiotics Metronidazole (Flagyl) penetrates microorganisms and, under anaerobic conditions, forms nitroso radicals with microbial pyruvate-ferredoxin oxidoreductase by oxidizing ferredoxin and flavodoxin. Nitroso radicals form compounds with DNA base pairs, which leads to DNA chain breakage and bacterial cell death.

Flagyl Dosage for Sinus Infection

Flagyl should be used with caution in patients suffering from epilepsy and CNS diseases with a reduced seizure threshold. In patients with severe liver damage and hematopoietic disorders (including granulocytopenia), Metronidazole should be used only if the expected benefit outweighs the potential risk.

Alcohol is prohibited during medical treatment, as a disulfiram-like reaction may occur (abdominal cramps and spasms, nausea, vomiting, headache, hot flashes).

Metronidazole dosage for sinus infection is 500 mg every 8 hours for adult people and children 12 years of age and older. Kids aged 2 to 12 years should take 7-10 mg of Metronidazole/kg of body weight every 8 hours, which corresponds to a daily dose of 20-30 mg of Metronidazole/kg of body weight. The dose may be adjusted according to the patient’s individual response to treatment, age, and body weight, as well as the type and severity of the disease.

The duration of treatment with Metronidazole or drugs containing other nitroimidazoles should not exceed 10 days. The treatment period can be extended only in specific cases with appropriate clinical and laboratory monitoring.

Can Flagyl Treat Sinus Infections?

The clinical practice guideline for the management of sinus infections states that oral antibiotics such as Flagyl are the first choice in most cases. They help to normalize the health condition, prevent serious complications, stop the development of the disease, and eradicate microflora.

Patrick Blin, Sylvie Blazejewski, Severine Lignot, et al. in their studies on acute sinusitis indicate that the main risk factor associated with the development of infection and its persistence is previous treatment. Antibiotic treatment poses a risk of resistance. Thus, the doctor must be attentive to the patient’s medical history and the use of antibiotics in the previous treatment cycles.


Flagyl is a broad-spectrum antibiotic that belongs to the nitroimidazole group and has high anaerobic activity. Its mechanism of action is associated with changes in the DNA structure of pathogenic microorganisms sensitive to the action of Metronidazole. These include Porphyromonas gingivalis, Prevotella denticola, Fusobacterium fusiformis, Moraxella catarrhalis, Streptococcus spp, Selenomonas spp, etc.

The list of diseases that Flagyl successfully treats is quite wide. But does Metronidazole work for sinus infection? Yes, the antibiotic does an excellent job of treating this disease, but before starting the cycle, it is important to get a preliminary consultation with a doctor in a reliable medical department.


Can Metronidazole be used for a sinus infection?

Metronidazole is commonly prescribed for sinusitis, even in pediatric practice. The medicine is effective against many anaerobic bacteria and protozoa that infect humans.

What is the best antibiotic for a sinus infection?

Nitroimidazole derivatives (for example, Flagyl), penicillin drugs, cephalosporins, and macrolides are the best antibiotics for sinus infections.

What type of infection is Metronidazole used for?

Metronidazole successfully copes with infections caused by protozoa and anaerobic bacteria.

What is the fastest way to get rid of a bacterial sinus infection?

Using proven antibiotics like Flagyl is the fastest way to get rid of bacterial sinusitis. But self-medication is prohibited; the drug must be prescribed by a medical specialist.