TADIM

What it is

Tadim is a sterile powder for nebuliser solution containing 1 million International Units (IU) of colistimethate sodium, which is approximately equivalent to 80 mg. Colistimethate sodium is a polypeptide antibiotic. The powder is reconstituted before use as a nebuliser solution.

Approved indications

— Treatment of colonisation and infections of the lung due to susceptible Pseudomonas aeruginosa in patients with cystic fibrosis.

Dosing overview

For children over 2 years, adolescents and adults, the recommended dose is 1–2 million IU two or three times daily using a conventional nebuliser. The dosage is determined by the severity and type of infection and renal function of the patient. Initial colonisation with Pseudomonas aeruginosa may be treated with a 3-week course of 2 million IU twice daily in conjunction with other parenteral or oral antibiotics. For frequent, recurrent infections, the dose may be increased up to a maximum of 2 million IU three times daily for up to 3 months, in conjunction with other parenteral or oral antibiotics. Chronic colonisation may require long-term therapy with 1 to 2 million IU twice daily. The dose placed into the nebuliser may be reduced if the patient is using an I-neb AAD nebuliser system.

Key safety warnings

Nebulisation of colistimethate sodium may induce coughing or bronchospasm, and a choking sensation has been reported in some cases. It is advisable to administer the first dose under medical supervision, and pre-dosing with a bronchodilator is recommended and should be routine, especially if this is part of the patient's current therapeutic regimen. Bronchial hyper-reactivity in response to colistimethate sodium may develop with continued use over time and it is recommended that pre- and post-treatment FEV₁ is evaluated at regular clinic visits. High serum concentrations of colistimethate sodium after intravenous or intramuscular administration may be associated with overdosage or failure to reduce the dosage in patients with renal impairment and may lead to neurotoxicity; concomitant use with either non-depolarising muscle relaxants or antibiotics with similar neurotoxic effects can also lead to neurotoxicity. Neurotoxic effects that have been reported include vertigo, transient facial paraesthesia, slurred speech, vasomotor instability, visual disturbances, confusion, psychosis and apnoea. Tadim should be used with extreme caution in patients with porphyria.

Contraindications

Tadim is contraindicated in patients with known hypersensitivity to colistimethate sodium. Colistimethate sodium is known to reduce the amount of acetylcholine released from the pre-synaptic neuromuscular junction and therefore should not be used in patients with myasthenia gravis.

Regulatory history

Tadim was first listed on the Australian Register of Therapeutic Goods (ARTG 165709) on 2 February 2011.