Dicloxacillin: Formula, Presentation, Indications, Mechanism of Action, Dosage and Side Effects

It is a drug with antibiotic properties belonging to the group of penicillins.

The conditions that combat includes bronchitis, pneumonia, and skin infections.

Chemical formula

  • C19H17N3Cl2O5S.


Dicloxacillin can be administered orally, in pill form, or injected, although its most common use is to administer it in the form of capsules.

In capsules containing dicloxacillin sodium monohydrate equivalent to 500 mg of anhydrous dicloxacillin.

In suspension, every 5 ml of the reconstituted suspension contains dicloxacillin sodium monohydrate equivalent to 250 mg and 500 mg of dicloxacillin.

In injectable solution in ampoules of injectable solution of 250 mg and 500 mg of dicloxacillin sodium.


The main indication for dicloxacillin is the treatment of penicillinase-producing staphylococcal infections, group A-beta pneumococcus, hemolytic streptococci, G-resistant penicillin, and G-staphylococcus-sensitive penicillin.


Dicloxacillin is indicated for pharyngitis, bronchitis, bronchopneumonia, and pneumonia with multiple foci.

Even in severe complications of pneumonia such as empyemas and pneumothorax, with or without the formation of pneumatoceles and pulmonary abscesses, caused by Staphylococcus aureus, including penicillinase producers.

It is used in these resistant and chronic pneumonia cases because this drug eliminates the pneumococci that produce this infectious disease.

In the fight against bronchitis, dicloxacillin is used to fight infections that occur in the bronchi, such as bronchitis, which are caused by pathogens such as Streptococcus, Bordetella pertussis, Mycoplasma pneumonia, and Chlamydophila pneumonia.

It is used to treat bacterial tonsillitis because this drug attacks Streptococcus pyogenes, a bacterium that usually stays in the respiratory tract for a time without being harmful.

However, when the immune system for some reason does not fulfill its function, these bacteria attack the organs, causing infections.

Dicloxacillin is recommended in cases where the bacterium Streptococcus pyogenes present resistance.

Dicloxacillin is also indicated in various skin and soft tissue infections such as Impetigo, bullous Impetigo, furunculosis, pyodermas, cellulitis, and hidradenitis, escalated skin syndrome such as Lyell’s syndrome, Ritter’s disease, wounds infected by Staphylococcus.

As well as in septic arthritis, Osteomyelitis, and pyomyositis.

Septic arthritis is a condition caused by the infection of a lesion near joints or, in the case of some pathogenic microorganisms that spread through the bloodstream, affecting the joints.

Dicloxacillin is also used in the treatment of chronic septic arthritis that is caused by pathogenic bacteria such as Candida albicans and Mycobacterium tuberculosis.

In infections such as bacterial cellulitis, this drug is administered to fight bacteria such as Staphylococcus aureus and Streptococcus, which cause infectious cellulitis in those areas where there is a scrape or cut.

Where these pathogens enter the skin of the patient organism infecting it and triggering bacterial cellulitis.

Osteomyelitis is a bone infection caused by pathogens such as Staphylococcus aureus.

The dicloxacillin change is indicated for treating internal infections in the bones since these pathogenic organisms usually show resistance to many antibiotics.

In general, it is used as a treatment for:

  • Pulmonary abscesses
  • The cutaneous affections by bacteria.
  • Tonsillitis
  • Septic arthritis
  • The bronchopneumonia.
  • Bronchitis.
  • The cellulitis (by bacteria).
  • The pulmonary empyemas.
  • Pharyngitis
  • The hidradenitis.
  • The Impetigo.
  • Pneumonia.
  • Multiple cases of pneumonia.
  • Las osteomyelitis.
  • The pyodermas.
  • Pyomyositis
  • The climbing skin syndrome.
  • The wounds infected by staphylococci.

Mechanism of action

Dicloxacillin is a drug whose use is very restricted and belongs to the group of antibiotics, which belongs to the group of penicillins.

It is used for the treatment of infections caused by bacteria.

This drug acts as an inhibitor in the growth of the bacterial cell wall destroying it.

Moreover, inhibiting cell wall synthesis in susceptible bacteria kills them.


In case of mild to moderate infections caused by susceptible microorganisms:

  • In children and adults with 40 kg or more bodyweight, administer 125 to 250 mg every 6 hours orally.
  • In children under 40 kg of body weight, administer 12.5 mg per kg per day orally in divided doses every 6 hours.

In those cases of moderate to severe, the administration is intravenous or intramuscular:

  • Administer 100 to 200 mg per kg per day intravenously for five days and then continue with the same doses administered orally until treatment is completed, approximately ten or more days.
  • In adults, a 500-mg ampule should be administered intramuscularly, every six hours or intravenously, diluted in 50 to 100 ml of sterile water by slow drip every six hours.

The duration and dose of treatment depend on the type of infection.

  • In the case of children under 12 years, the dose is 12.5 mg per kg per day for those mild to moderate infections and 25 mg per kg per day for severe infections, every 6 hours, for the indicated time by the doctor.
  • In the case of adults and young people older than 12 years, the dose in most indications usually is to administer a capsule of 500 mg every 6 hours for 10 to 14 days.

In infections caused by group A beta-hemolytic streptococci, the treatment lasts no less than ten days to help prevent the onset of rheumatic fever or acute glomerulonephritis.

Dicloxacillin is better absorbed without food in the stomach, so it is advisable to administer it one hour before or two hours after the main meals.

Side effects

Generally, the absorption of dicloxacillin usually does not present side effects. However, discomforts such as abdominal pains, diarrhea, nausea, headaches, irritation, or vaginal discharge have been reported on certain occasions.

If these effects appear and do not disappear with the passing of days or worsen in the worst case, you should go to the doctor.

Also, when dicloxacillin is administered, symptoms such as watery or bloody diarrhea, some signs of allergy, such as skin lesions, and breathing difficulties.

As well as swelling in the face, lips, tongue or throat, feverish pictures, coughs, weaknesses, rashes on the skin, or any other type of discomfort.

Warnings and contraindications

This drug should not be used if the patient has allergic reactions to the component or other beta-lactam antibiotics, including penicillin, ampicillin, and amoxicillin.

In cases of allergies to the drug, symptoms such as nausea, vomiting, flatulence, bad breath, gastrointestinal disorders, epigastric pain, and anaphylactic reactions may occur.

Urticaria, pruritus, itching, and mild liver problems such as jaundice and elevated transaminase levels.

It is not advisable in young children or people with chronic diseases or if the patient suffers from any pathology such as asthma, liver or kidney disease, interstitial nephritis, angioneurotic edema, anaphylactic shock, or blood diseases, any allergy to food or medication.

This medication must be administered for as long as the doctor prescribes, even if the disease symptoms have disappeared before the end of treatment.

Antibiotics can usually cause diarrhea, which in some cases indicates another infection’s presence.

The treatment should be stopped immediately, and the doctor should be consulted if the patient perceives watery diarrhea or accompanied by blood.

Dicloxacillin is not the indicated treatment for viral diseases such as flu, influenza, and other diseases caused by viruses.

Dicloxacillin can be administered during pregnancy or lactation, always by prescription and under strict medical supervision.


  • The administration of dicloxacillin combined with tetracyclines is not recommended.
  • It is recommended not to consume alcohol while the medication is consumed.

Indiscriminate use

Dicloxacillin is a drug usually administered in treatments against bacteria that have shown resistance to the action of other penicillins.

It also has a specific function for certain infections, in the infestations of bacteria such as:

Bordetella pertussis, Chlamydophila pneumonia, Staphylococci, Hemolytic Streptococcus, Mycoplasma pneumonia, Pneumococcus, and Streptococcus, are useless in other bacterial infections.

This drug is used to treat resistant bacterial infections; it is usually used alone and only after having experienced other types of less “strong” antibiotics.

Its application should not be prolonged because, in cases of prolonged treatment, there may be some complications such as fungal infestations or the infection of bacterial “opportunists.”

This happens when eliminating or altering the normal microbiota, which are those microorganisms that perform beneficial functions in the body; other harmful and opportunistic microorganisms invade the organs.

Another harmful effect of the indiscriminate use of antibiotics is the resistance of bacterial pathogens to drugs, which has, consequently, the mutation to super bacteria resistant to antibiotics.