Dicloxacillin

Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.

Distaph (Alphapharm)
250 mg and 500 mg capsules

Indication: specified infections
Following concern about the risk of cholestatic hepatitis after treatment with flucloxacillin, effective alternatives are being sought.1 Dicloxacillin is one alternative, but it is not known if the risk of jaundice is significantly less than with flucloxacillin.

Dicloxacillin is an isoxazolyl penicillin which is not inactivated by beta lactamase. This makes the drug effective in the treatment of staphylococcal infections. Its indications therefore resemble those of flucloxacillin.

When dicloxacillin is taken 1-2 hours before food, it is rapidly absorbed. The bioavailability is 50-94% and dicloxacillin is almost completely bound to plasma proteins. Approximately half the absorbed dose is metabolised and excreted, with the unchanged fraction, in the urine. In patients with severe renal impairment, it is suggested that the dose interval be increased from every 6 hours to every 8 hours.

The adverse effects of dicloxacillin are similar to those of flucloxacillin. They include hypersensitivity reactions (penicillin allergy is a contraindication) and gastrointestinal symptoms. As well as rarely causing hepatitis, dicloxacillin can also cause pseudomembranous colitis.

Until the incidence of hepatitis is known, it may be best to use other alternatives to flucloxacillin.1