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Nhiem virut viem gan B - Khi nao can dung thuoc?
Trong khoang 5 nam tro lai day, chung ta co them nhieu thuoc chua viem gan sieu vi B man. Ben canh do cung xuat hien su khang thuoc, xuat hien nhieu chung khang thuoc dot bien gen... nen phuong phap dieu tri, dung thuoc, cham soc co mot so thay doi...
Thuc te, nguoi bi nhiem virut viem gan B (HBV) thuong lo lang ve tinh trang benh va ban khoan khong biet nen dung thuoc hay khong. Neu dung thi dung nhu the nao?




Co phai cu nhiem HBV la dung thuoc?

HBV phan lam 4 truong hop:

- Truong hop 1: Co khang nguyen be mat HBsAg (+) chung to co virut;  co khang nguyen noi sinh HBeAg (+) chung to virut dang sinh soi, co dau hieu lam sang viem gan B ro (vang mat, vang da, met moi chan an; enzym gan  ALT-alanin aminotranferase tang. Binh thuong ALT= 40U/L, khi bi benh ALT tang gap 2 lan tro len). Day la truong hop  can phai  dung thuoc.

- Truong hop 2: HBsAg (+) chung to co virut; HBeAg(-) chung to khong co dau hieu virut sinh soi; khong co dau hieu lam sang ro. Day la truong hop nguoi lanh mang mam benh, khong dung thuoc.

- Truong hop 3: HBsAg (+) chung to co virut; HBeAg(+) chung to virut dang sinh soi, nhung khong co dau hieu lam sang. Day la truong hop nguoi "dung nap duoc mien dich" cung chua can dung thuoc. Nhung truong hop nay co nguy co cao, virut co the tai kich hoat gay benh nen can theo doi, neu thay xuat hien cac bieu hien lam sang thi kham ngay de kip thoi dung thuoc.

- Truong hop 4: HBsAg (+) chung to co virut; HBeAg (-) chung to khong co dau hieu virut sinh soi nhung lai co dau hieu lam sang. Day la truong hop nguoi benh da tung bi viem gan B man, virut tung kich hoat am tham, sau do ngung kich hoat goi la nguoi viem gan B khong hoat tinh; chua can dung thuoc (vi virut chua tai sinh soi, chua thuc su tai kich hoat, dung se khong co loi). Tuy nhien phai theo doi chat che: kham lam sang, xet nghiem dinh ky, khi can thiet phai can thiep ngay.

Thuoc dieu tri viem gan B man

+ Interferon: Co hieu nang tang cuong kha nang mien dich, ngoai ra con khang virut. Thuoc bi thuy phan o duong tieu hoa nen chi dung duong tiem.  Khi dung, mot so nguoi benh co the gap cac trieu chung nhu sot, rung toc, met... Tuy nhien, gia thanh cua thuoc con cao, lai phai dung lau dai nen nhieu truong hop khong co dieu kien. Vi the, thuoc tuy rat tot nhung it nguoi benh lua chon.

+ Lamivudin: Co hieu nang khang virut. Khi dung du lieu trinh thi dau hieu lam sang mat di, ALT tro ve binh thuong, luong virut (HBVDNA) giam, hinh anh mo hoc gan cai thien. Thoi gian dat duoc muc tieu nay le thuoc vao tung nguoi, it nhat la 1 nam, trung binh 2 nam, co khi keo dai toi 3 nam, neu tai phat con co the dung lai. Truoc nam 2000, lamivudin duoc xem la thuoc dau tay (re tien, dung duong uong, tien loi). Nhung hien nay ty le khang lamivudin len  toi 70% (lamivudin bi khang thuoc theo kieu gen) nen hien khong duoc ua dung nhieu. Tuy nhien, cung co khoang 20% nguoi benh hau nhu khong bi khang thuoc. Can luu y dieu nay de co the dung lamivudin cho nguoi co kha nang dap ung, nhat la voi nguoi kinh te kho khan (lamivudin van la thuoc co gia re).

+ Adefovir, entecavi, telbivudin:  Thoi gian dat duoc muc tieu dieu tri ngan hon lamivudin. Ty le khang thuoc thap hon lamivudin va co hieu qua voi nhung nguoi benh da khang voi lamivudin.

+ Tenofovir: La thuoc moi nhat duoc EU (My) moi cho dung nam 2008. Qua cac nghien cuu cho thay tenofovir tot hon cac thuoc truoc do ca ve muc dat duoc hieu qua va  chua bi khang thuoc.

+ Dung phoi hop thuoc: May nam gan day, co mot so nghien cuu phoi hop thuoc trong dieu tri viem gan sieu vi B. Phoi hop chat tang cuong mien dich (interferon- pegylat) voi chat khang virut (lamivudin) cho ket qua tot hon dung moi thu rieng le, nhung phoi hop hai chat khang virut thi cho ket qua khong deu. Chang han dung lamivudin+ adefovir voi nguoi da bi khang lamivudin thi tinh tren nguoi dung co 80% co dap ung, 80% giam HBVDNA den muc khong phat hien duoc, 84% ALT tro lai binh thuong. Sau khi ngung dung 3 nam khong nhan thay co su bung no dao nguoc ve virut hay lam sang  hoc, khong hinh thanh su de khang kieu gen, khong mat bu tru o nguoi xo gan. Nhung co truong hop khong cho ket qua tot hon. Chang han: dung lamivudin+ telbivudin thi tot hon dung rieng lamivudin nhung lai khong tot hon dung rieng telbivudin. Vi su phoi hop chua on dinh, hon nua lam tang chi phi dieu tri nen cac nghien cuu nay chua ap dung lam sang.

Khi nao ngung dung thuoc?

Tai luong HBV cang cao (so luong ban sao HBVDNA/1ml mau lon) thi nguy co xo gan, ung thu gan cang lon. Tai luong HBV la yeu to tien doan doc lap cho su phat trien xo gan, ung thu gan. Nong do ALT cang cao thi nguy co xo gan, ung thu gan cung cang lon. Vi the, khi dieu tri viem gan sieu vi B man, can dua HVNDNA ve duoi nguong va dua ALT ve muc binh thuong moi ngung thuoc. Sau khi ngung thuoc, can theo doi dinh ky, ke ca nguoi benh ma khi ngung dieu tri HBVDNA o nguong thap.

Chi dung thuoc khi hoi du cac tieu chi (truong hop 1) va ngung dieu tri  khi dat muc dich dieu tri. O cac benh vien tuyen tren, thuong xet nghiem HBVDNA. Day la chi so cho biet tinh trang sinh san (nhan doi te bao) cua virut. HBVDNA (+) chung to virut dang sinh soi (khi dieu tri HBVDNA thuong giam, ly tuong la dat den muc khong con HBVDNA, nhung trong thuc te chi co the dat duoc muc toi da, tuc la van co the con HBVDNA nhung khong con phat hien duoc bang cac phuong phap thong thuong). Co luc HBVDNA chi giam den mot muc nhat dinh. Vi du luc dau, HBVDNA = 200.000 ban sao/1ml mau, sau dieu tri chi con 300 ban sao/1ml mau thi coi nhu benh da on dinh, co the ngung thuoc.

Hien co xuat hien su khang thuoc, dac biet xuat hien cac chung khang thuoc dot bien gen.  Khi da  dieu tri du lieu trinh, dat ket qua, cho ngung thuoc thi van theo doi dinh ky de xu ly viec bung phat virut. Khi bi khang thuoc, can chap nhan mot lieu trinh khac, khong bi quan bo mac vi co the bot phat nguy hiem. Khong tu y dung thuoc cung nhu tu y bo do dieu tri, tu y keo dai thoi gian dieu tri. Trong qua trinh dieu tri, can kham va xet nghiem dinh ky. Trong truong hop  khong hoac chua dung thuoc (truong hop 2- 3- 4) thi can hieu ro loi dan thay thuoc, tu theo doi chat che, khi can phai kham, xet nghiem ngay (truong hop 3- 4).

Hien co nhieu loai thuoc duoc danh gia la co hieu nang, nhung khac nhau ve muc dat duoc hieu qua, su khang thuoc, thoi gian dieu tri, gia ca. Khi thao luan, nguoi benh can  nghe du cac thong tin, trinh bay nguyen vong de thay thuoc can cu vao do va tinh trang benh ma chon lieu trinh thich hop.


Theo SK&DS