Dicloxacillin: Indications, Dose, How to Take & Side Effects

Dicloxacillin is an antibiotic that belongs to the penicillin group. Its main role is to kill bacteria that can cause infections in different parts of the body.

It is commonly prescribed for infections caused by Staphylococcus aureus or Streptococcus pneumoniae. Dicloxacillin is also used when bacteria are suspected to produce penicillinase, an enzyme that can make other antibiotics ineffective.

This medication should never be taken without medical guidance, as improper use may lead to bacterial resistance.

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Indications for use

Dicloxacillin is used to treat several bacterial infections, including:

  • Acute pharyngitis

  • Pneumonia

  • Bacterial bronchitis

  • Skin and soft tissue infections, such as boils or cellulitis

Dicloxacillin is not effective against viruses, such as those that cause colds or the flu.

Dicloxacillin dosage

The dosage of dicloxacillin depends on the type of infection and the form of the medication. It should always be prescribed by a healthcare professional.

Presentation Concentration Recommended dose
Capsules 250 mg and 500 mg Adults: 250 to 500 mg every 6 hours, or as directed by a doctor. Maximum daily dose: 6 g.
Oral suspension 125 mg/5 ml or 250 mg/5 ml Adults: 250 to 500 mg every 6 hours, or as directed by a doctor. Maximum daily dose: 6 g.
Children: 12.5 to 25 mg/kg/day divided every 6 hours, or as directed by a doctor. Maximum daily dose: 1–2 g.    
Injectable (IM or IV) 250 mg or 500 mg per vial Adults: 500 mg every 6 hours, as directed by a doctor.

The oral suspension is particularly useful for children or for people who have trouble swallowing capsules, but it can also be prescribed for adults.

How to take

Dicloxacillin capsules should be swallowed whole, without opening or chewing, on an empty stomach (at least 1 hour before or 2 hours after meals) and with a full glass of water.

How to prepare the suspension

To prepare the oral suspension, gradually add the amount of water specified on the package, shaking well after each addition until the powder is completely dissolved.

Boiled and cooled or purified water is usually recommended. The bottle should always be shaken before each dose to ensure the medication is evenly mixed.

Once prepared, the suspension is typically stored in the refrigerator and remains stable for 7 to 14 days, depending on the brand. It should not be frozen, and any leftover medication after this period should be discarded.

Possible side effects

Common side effects of dicloxacillin may include:

  • Abdominal pain

  • Diarrhea

  • Nausea

Other possible effects include rash, itching, or hives. In rare cases, dicloxacillin can cause a severe allergic reaction with symptoms such as difficulty breathing or swelling of the face and throat. Less common side effects may involve liver function changes, anemia, fever, or pseudomembranous colitis.

If severe diarrhea or allergy symptoms occur, seek medical care right away.

Contraindications of dicloxacillin

Dicloxacillin is contraindicated in people allergic to penicillins, cephalosporins, or imipenem. It should not be used during pregnancy or breastfeeding without medical supervision.

This antibiotic should not be given together with live bacterial vaccines and must be used with caution in people who have a history of severe allergic reactions.

Dicloxacillin can also decrease the effectiveness of hormonal contraceptives, so an additional form of birth control is recommended during treatment.