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.

Tequin, Tequin IV (Bristol-Myers Squibb)
400 mg film-coated tablets
infusion bags containing 400 mg/200 mL
Approved indication: specified infections
Australian Medicines Handbook Section 5.1.12

Gatifloxacin is a fluoroquinolone antibiotic with a wide range of activity. It is active against aerobic gram-positive and gram-negative bacteria, and also Chlamydia pneumoniae, Legionella pneumophila and Mycoplasmapneumoniae. This makes gatifloxacin suitable for the treatment of respiratory infections such as community-acquired pneumonia.

In patients with community-acquired pneumonia, gatifloxacin is as effective as clarithromycin and ceftriaxone. However, these drugs are not usually the first-line therapy in Australia. Gatifloxacin has also not been compared with first-line drugs for acute exacerbations of chronic bronchitis, but it is as effective as cefuroxime for this indication.

The antibacterial activity of fluoroquinolones includes Neisseria gonorrhoeae. Gatifloxacin can therefore be used to treat uncomplicated urethral, pharyngeal and rectal gonorrhoea in men and endocervical, pharyngeal and rectal gonorrhoea in women.

Gatifloxacin has a half-life of 7-14 hours and is given once a day. It is well absorbed with the result that the oral formulation has similar pharmacokinetics to the intravenous formulation. The concentration of the drug in some target organs, e.g. lung parenchyma, is greater than the serum concentration. Most of the dose is excreted unchanged in the urine, so an adjustment is needed if the patient has renal impairment.

Dysuria and haematuria are adverse effects, but more common problems include nausea, vomiting, diarrhoea and vaginitis. As gatifloxacin may prolong theQTc interval it should be avoided in patients with hypokalaemia and in those taking drugs such as tricyclic antidepressants. Gatifloxacin can also alter blood glucose concentrations and may increase the risk of patients being treated for diabetes developing hypoglycaemia.

Like other fluoroquinolones, gatifloxacin should be kept in reserve, for occasions when a cheaper drug is not effective.