Hopkins ABX Guide

Dicloxacillin Antibiotic

What is Dicloxacillin and When It is Used?

Dicloxacillin is an antibiotic from the penicillin group of antibiotics. It is a narrow-spectrum, beta-lactamase resistant penicillin and works against Gram-positive bacteria. Like other beta-lactamase resistant penicillins, dicloxacillin works against bacteria that are resistant to other penicillins such as Staphylococcus aureus and helps clear up bacterial infections by inhibiting bacterial growth. More specifically, it interferes with the production of bacterial cell walls and by doing so, effectively prevents the bacteria from growing.

This antibiotic is used to treat all kinds of bacterial infections including infections of the skin (cellulitis, furuncles, carbuncles, mastitis and impetigo), ears, urinary tract, pneumonia and more. While being effective against Staphylococcus aureus and other species from the Staphylococcus genus, dicloxacillin unfortunately isn’t effective against methicillin-resistant Staphylococcus aureus (MRSA). Even though the antibiotic was designed to be insensitive to beta-lactamase that is produced by some bacteria to counter the effect of other penicillins, MRSA has developed resistance to all beta-lactamase resistant penicillins including dicloxacillin.

How is Dicloxacillin Taken/Administered?

Dicloxacillin is available in the form of oral capsules and liquid, and is typically taken every six hours on an empty stomach. Though symptoms of the infection may resolve before completing the treatment, it is highly important to continue taking the medication and complete the entire course for the infection to clear up completely. Otherwise, the infection can come back because it takes only a few disease-causing bacteria to survive to cause illness again. In addition, the surviving bacteria are less susceptible to the effects of antibiotic and as a result, the infection can be very difficult to treat.

The antibiotic may also be given intravenously.

Side Effects of Dicloxacillin

Dicloxacillin may cause side effects. The most common ones include diarrhoea, stomach upset/pain, nausea and pain/redness at the injection site. Rarely, it can cause serious side effects including cholestatic hepatitis/jaundice and severe intestinal infection with the bacterium Clostridium difficile. Allergic reactions are relatively uncommon but it is necessary to seek medical care immediately if developing skin rash or hives, swelling in the face or mouth or/and having difficulties breathing. Prolonged use of the antibiotic can also cause vaginal yeast infection and thrush. Side effects can develop during or after the treatment.