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 include 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, where each 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, pneumonias with multiple foci.

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

It is used in cases of these resistant and chronic pneumonias, 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 pneumoniae and Chlamydophila pneumoniae.

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

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

Dicloxacillin is recommended in those cases in which the bacterium Streptococcus pyogenes presents resistance.

Dicloxacillin is also indicated in a wide variety of skin and soft tissue infections such as: Impetigo, bullous impetigo, furunculosis, pyodermitis , cellulitis, 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 a bacterial cellulitis.

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

The dicloxacillin change is indicated for the treatment of 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.
  • The pneumonias.
  • Multiple pneumonias.
  • Las osteomielitis.
  • The pyodermitis.
  • Pyomyositis
  • The climbing skin syndrome.
  • The wounds infected by staphylococci.

Mechanism of action

The dicloxacillin is a drug whose use is very restricted, 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.

And by inhibiting cell wall synthesis in susceptible bacteria, it kills them.


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

  • In children and adults of 40 kg or more of body weight, 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 in divided doses every 6 hours orally.

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 serious infections, every 6 hours, for the indicated time by the doctor.
  • In the case of adults and young people older than 12 years, usually the dose in most indications is to administer a capsule of 500 mg every 6 hours, for 10 to 14 days.

In infections that are caused by group A beta hemolytic streptococci, the treatment lasts no less than 10 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, but in certain occasions the presence of discomforts such as abdominal pains, diarrhea, nausea, headaches, irritation or vaginal discharge among others have been reported.

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

Also in the case that when dicloxacillin is administered, symptoms such as watery or bloody diarrhea, some signs of allergy, such as skin lesions, 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 had allergic reactions to the component or any other type of beta-lactam antibiotic, 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 some mild liver problems such as jaundice and elevated transaminase levels.

It is not advisable in young children or in 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 , blood diseases, any allergy to food or medication.

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

Antibiotics can usually cause diarrhea, which in some cases is indicative of the presence of another infection.

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 that is 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 pneumoniae, Staphylococci, Hemolytic Streptococcus, Mycoplasma pneumoniae, Pneumococcus, Streptococcus, being useless in other bacterial infections.

As 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 in the indiscriminate use of antibiotics is the resistance of bacterial pathogens to drugs, which has as a consequence the mutation to super bacteria resistant to antibiotics.