Since the 1960s, 5-fluorouracil has been the base drug for the treatment of gastrointestinal malignancies, and the vast majority of regulated regimens for the treatment of gastrointestinal tumors still contain 5-Fu or its derivatives.
Ingredients.
S-1 is a fluorouracil derivative oral anticancer agent consisting of three components, tegafur, gimostat and potassium oxyzate, in the molar ratio of 1:0 and 4:1.
The mechanism of action of these three components.
1.FT is a precursor drug of 5-Fu with excellent oral bioavailability and can be converted into 5-Fu in living body. by inhibiting thymidylate synthase, it prevents the conversion of deoxyuridine into deoxythymidine, thus interfering with the synthesis of DNA.
2. CDHP can inhibit the catabolism of 5-Fu released from FT under the action of dihydropyrimidine dehydrogenase, which contributes to the effective depth of 5-Fu in blood and tumor tissues for a long time, thus achieving similar efficacy as 5-Fu continuous intravenous infusion.
3. Oxo can block the phosphorylation of 5-Fu, and after oral administration, Oxo has a high distribution concentration in gastrointestinal tissues, thus affecting the distribution of 5-Fu in the gastrointestinal tract and thus reducing the effect of 5-Fu toxicity.
S-1 has the following advantages compared with 5-Fu.
(1) The ability to maintain high blood concentrations and improve anticancer activity.
(2) Significant reduction in drug toxicity.
(3) Easy administration.
In Japan, S-1 was approved for the treatment of advanced gastric cancer in 1999, head and neck cancer in 2001, colorectal cancer in 2003, and non-small cell lung cancer in 2004. Years of clinical application have proven that S-1 is a safe and effective anti-cancer drug. According to statistics, S-1 is currently used in more than 80% of cases of chemotherapy for advanced gastric cancer in Japan, with a treatment efficiency of 44,6%.
Indications: Stomach cancer, head and neck tumors.
Usage dosage.
1. For patients with body surface area less than 1.25 square meters, use 40mg twice a day. Take after breakfast and dinner. 28 days as a cycle and repeat at 14 days interval.
2. For patients with a body surface area between 1.25 m2 and 1.5 m2, take 50 mg twice a day after breakfast and dinner. Take after breakfast and dinner. 28 days as a cycle, repeat at 14 days interval.
3. For patients with a body surface area of more than 1.5 m2, take 60 mg twice a day after breakfast and dinner. Take after breakfast and dinner. 28 days as a cycle, repeat at 14-day intervals.
4.If the patient has normal liver and kidney function, normal blood sampling and no gastrointestinal discomfort during the dosing period, the interval can be shortened to 7 days. Each dosage can be adjusted up to 50mg, 60mg, 75mg in sequence.
5. It cannot be used in combination with other fluorouracil drugs and antifungal drugs.
Adverse reactions.
1.Bone marrow suppression.
2.hepatic impairment, loss of appetite, elevated transaminases.
3, Incidence of severe diarrhea 0.4%.
4, Incidence of severe enteritis 0.2%.
5.Incidence of interstitial pneumonia 0.4%.
6. 0.2% incidence of severe oral ulcers and bleeding.
7.Acute renal failure may occur.
8.Dermal toxicity may occur.
9.Sniffing disorder may occur.