Raltitrexed (Tomudex™) is an analogue of folic acid with a strong inhibitory activity towards thymidilate synthetase.
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Compared to the indirect action of 5-FU or methotrexate, raltitrexed acts by direct and specific inhibition of thymiylate synthetase which is necessary for de novo synthesis of triphosphate thymidine.
Raltitrexed penetrates cells via the folic acid transport system. Inside the cell, it undergoes intensive polyglutamation by the folyl-polyglutamate synthetase enzyme. It therefore remains bound inside the cell.
Raltitrexed prescribed alone has the same efficiency as the combination of 5-FU and folinic acid in colic carcinoma.
The usual dosage is 3 mg/m2 every 3 weeks, under regular haemogram monitoring.
Only specific toxicities (or major toxicities) are described here. Other common chemotherapy toxicities are described in the chapter on chemotherapy toxicity.
Digestive toxicity
Diarrhoea is very frequent, but generally of moderate intensity. However, it can suddenly become severe after raltitrexed infusion. In association with leucopaenia, severe diarrhoea requiring hospitalisation may be observed.
Skin toxicity
Various non intense eruptions.