Tegafur
Drug group: Antineoplastic Agents
Tegafur (INN, BAN, USAN) is a prodrug of Fluorouracil (5-FU), an antineoplastic agent used as the treatment of various cancers such as advanced gastric and colorectal cancers. It is a pyrimidine analogue used in combination therapies as an active chemotherapeutic agent in conjunction with Gimeracil and Oteracil, or along with Fluorouracil as Tegafur-uracil. Tegafur is usually given in combination with other drugs that enhance the bioavailability of the 5-FU by blocking the enzyme responsible for its degradation, or serves to limit the toxicity of 5-FU by ensuring high concentrations of 5-FU at a lower dose of tegafur. When converted and bioactivated to 5-FU, the drug mediates an anticancer activity by inhibiting thymidylate synthase (TS) during the pyrimidine pathway involved in DNA synthesis. 5-FU is listed on the World Health Organization's List of Essential Medicines
Mechanism of effect
The transformation of 2'-deoxyurindylate (dUMP) to 2'-deoxythymidylate (dTMP) is essential in driving the synthesis of DNA and purines in cells. Thymidylate synthase catalyzes the conversion of dUMP to dTMP, which is a precursor of thymidine triphosphate (TTP), one of the four deoxyribonucleotides required for DNA synthesis. After administration into the body, tegafur is converted into the active antineoplastic metabolite, fluorouracil (5-FU). In tumour cells, 5-FU undergoes phosphorylation to form the active anabolites, including 5-fluorodeoxyuridine monophosphate (FdUMP). FdUMP and reduced folate are bound to thymidylate synthase leading to formation of a ternary complex which inhibits DNA synthesis. In addition, 5-fluorouridine-triphosphate (FUTP) is incorporated into RNA causing disruption of RNA functions
Pharmacokinetics
Absorption
Tegafur displays a dose-proportional pharmacokinetic properties. Tegafur is rapidly and well absorbed into the systemic circulation, reaching the peak plasma concentration within 1 to 2 hours of administration.
Metabolism
Hepatic CYP2A6 is the predominant enzyme that mediates 5-hydroxylation of tegafur to generate 5'-hydroxytegafur. This metabolite is unstable and undergoes spontaneous degradation to form 5-FU, which is an active antineoplastic agent that exerts a pharmacological action on tumours. 5-FU is rapidly metabolised by the liver enzyme dihydropyrimidine dehydrogenase (DPD
Half life
The elimination half life of tegafur is approximately 11 hours.
Excretion
Following oral administration, about less 20% of total tegafur is excreted unchanged in the urine.
Tegafur displays a dose-proportional pharmacokinetic properties. Tegafur is rapidly and well absorbed into the systemic circulation, reaching the peak plasma concentration within 1 to 2 hours of administration.
Metabolism
Hepatic CYP2A6 is the predominant enzyme that mediates 5-hydroxylation of tegafur to generate 5'-hydroxytegafur. This metabolite is unstable and undergoes spontaneous degradation to form 5-FU, which is an active antineoplastic agent that exerts a pharmacological action on tumours. 5-FU is rapidly metabolised by the liver enzyme dihydropyrimidine dehydrogenase (DPD
Half life
The elimination half life of tegafur is approximately 11 hours.
Excretion
Following oral administration, about less 20% of total tegafur is excreted unchanged in the urine.
Drug indications
Indicated for the treatment of cancer usually in combination with other biochemically modulating drugs.
Indicated in adults for the treatment of advanced gastric cancer when given in combination with Cisplatin.
Indicated for the first-line treatment of metastatic colorectal cancer with Uracil and calcium folinate.
Indicated in adults for the treatment of advanced gastric cancer when given in combination with Cisplatin.
Indicated for the first-line treatment of metastatic colorectal cancer with Uracil and calcium folinate.
Drug forms
Ai Yi (Hengrui) / ESUEEW AN T (Sawai Seiyaku) / Fimer (LKM) / Ftorafur (Grindeks) / Furil (Lotus Pharmaceuticals)
User's questions
No comments yet.
Ask a Pharmacist