UROMITEXAN

What it is

Uromitexan contains mesna, a synthetic sulphydryl compound designated as sodium 2-mercapto-ethane sulphonate. Uromitexan tablets are white, oblong, biconvex film-coated tablets, scored on one side and marked "M 4" or "M 6", containing 400 mg or 600 mg (respectively) of mesna.

Approved indications

— Reduction and prevention of urinary tract toxicity (haemorrhagic cystitis) of oxazaphosphorines.

Dosing overview

For intermittent oxazaphosphorine therapy, oral mesna 40 per cent (w/w) of the oxazaphosphorine dose should be given 2 hours prior to the oxazaphosphorine dose, and repeated at 2 and at 6 hours after oxazaphosphorine administration. Alternatively, an initial intravenous dose of mesna (20 per cent (w/w) of the oxazaphosphorine dose) can be given with the cytotoxic dose and additional oral mesna, 40 per cent (w/w) of the oxazaphosphorine, given at 2 and 6 hours. Children may require shorter intervals between doses and/or an increased number of individual doses due to increased micturition. Those who have had previous irradiation of the small pelvis, occurrence of cystitis during previous cyclophosphamide or ifosfamide therapy or a history of urinary tract lesions may require shorter intervals between doses and/or an increased number of doses.

Key safety warnings

Severe allergic symptoms, such as systemic anaphylactic reactions, have occurred with mesna, especially in patients suffering from autoimmune diseases. Due to the possibility of anaphylactoid reactions, it should be ensured that adequate emergency medication is available. Patients with autoimmune diseases who were treated with cyclophosphamide and Uromitexan appeared to have a higher incidence of hypersensitivity reactions including skin and mucosal reactions of varying extent and severity (rash, itching, redness, severe bullous and ulcerative skin, vesiculation, Lyell Syndrome, Stevens-Johnson Syndrome, toxic epidermal necrolysis, erythema exudative multiforme), localised or generalised urticarial or other forms of exanthema, pruritus, burning, local tissue swelling (urticarial oedema), angioedema and/or flushing. The protective effect of mesna applies only to the urothelial toxic effect of oxazaphosphorines (viz. ifosfamide or cyclophosphamide) not to their renal and other toxic effects. Uromitexan does not prevent haemorrhagic cystitis in all patients. As a result, a morning specimen of urine should be examined for the presence of haematuria (microscopic evidence of red blood cells) and proteinuria each day prior to oxazaphosphoraine therapy.

Contraindications

Uromitexan is contraindicated in individuals with a known hypersensitivity to mesna or any of the excipients and other thiols.

PBS listing

PBS listings are available for the solution for intravenous injection 400 mg in 4 mL ampoule (2 items, restricted, ex-manufacturer price A$51.74) and the 1 g in 10 mL ampoule (2 items, restricted, ex-manufacturer price A$117.16). The tablet formulation is not listed on the PBS.

Regulatory history

Uromitexan mesna injection ampoules were first listed on the ARTG on 21 October 1993. The 400 mg and 600 mg tablet formulations were first registered on the ARTG on 28 August 1996.