ARX-DICLOXACILLIN

What it is

ARX-DICLOXACILLIN is dicloxacillin sodium capsules available in 250 mg and 500 mg strengths. Dicloxacillin sodium is a semisynthetic penicillin that resists inactivation by staphylococcal β-lactamase (penicillinase). Penicillinase resistant penicillins exert a bactericidal action against penicillin-susceptible microorganisms during active multiplication by inhibiting the biosynthesis of the bacterial cell wall.

Approved indications

— Treatment of confirmed or suspected staphylococcal and other Gram positive coccal infections, including skin and skin structure and wound infections — Treatment of infected burns — Treatment of cellulitis — Treatment of osteomyelitis — Treatment of pneumonia

Dosing overview

For mild to moderate infections in adults and children more than 12 years of age, the dose is 250 mg six hourly, with dosage doubled in more severe infections. The capsules should be administered on an empty stomach, one to two hours before food. The duration of treatment varies with the type and severity of infection as well as the overall condition of the patient, and treatment duration should be determined by the clinical and bacteriological response of the patient. In severe renal impairment, the dosing interval may be increased to 8 hourly but no change in the individual dose is needed.

Key safety warnings

Serious and occasionally fatal hypersensitivity (anaphylactoid) reactions have occurred in patients receiving penicillin, and serious anaphylactic reactions require immediate emergency treatment with adrenaline (epinephrine). There is clinical and laboratory evidence of cross-allergenicity among bicyclic β-lactam antibiotics including penicillins, cephalosporins, cephamycins, 1-oxa-β-lactams and carbapenems. Antibiotic associated pseudomembranous colitis has been reported with dicloxacillin, with a toxin produced by Clostridium difficile appearing to be the primary cause, and the severity may range from mild to life threatening. It is important to consider this diagnosis in patients who develop diarrhoea or colitis in association with antibiotic use, which may occur up to several weeks after cessation of antibiotic therapy. Dicloxacillin has been associated with cholestatic hepatotoxicity and jaundice, with patterns of liver function test results and biopsy histology similar to those with flucloxacillin. Dicloxacillin should only be used in older patients (55 years or more) when such use is clearly justifiable on clinical grounds. Rare reports have been received of oesophageal burning, oesophagitis and oesophageal ulceration, particularly after ingestion of dicloxacillin capsules with an insufficient quantity of water and/or before going to bed; dicloxacillin should be taken with at least 120 mL of water and should NOT be taken in the supine position or immediately before going to bed.

Contraindications

ARX-DICLOXACILLIN is contraindicated in patients with a history of previous hypersensitivity reaction to any penicillins or to any component of the formulation.

PBS listing

No information regarding PBS listing is provided in the source documents.

Regulatory history

ARX-DICLOXACILLIN 500 mg capsules (ARTG 391292) and 250 mg capsules (ARTG 391293) were first listed on the Australian Register of Therapeutic Goods on 21 July 2023.