Cac phan ung phu cua thuoc

Thứ bảy, 02 Tháng mười 2010, 22:58 GMT+7

Phan ung phu cua thuoc la nhung ton thuong hoac nhung dap ung khong mong muon doi voi mot loai thuoc duoc dung voi muc dich dieu tri. Cac phan ung nay khong chi gay ra cac bieu hien co hai cho nguoi benh ma con co the anh huong den chat luong dieu tri va tien luong benh.

Phan ung phu do thuoc co nhieu dang khac nhau, pho bien nhat la cac tac dung phu lien quan den tac dung duoc ly cua thuoc, bieu hien di ung thuoc, nhiem doc va tuong tac thuoc. Phan ung phu thuong xay ra do dung thuoc khong dung chi dinh, khong dung lieu hoac khong dung cach nhung co the xay ra ngay ca khi dung thuoc dung. Mac du hau het cac phan ung phu do thuoc gay ra do cac loai thuoc ke don nhu khang sinh, thuoc ha huyet ap, loi tieu, thuoc gian phe quan, thuoc chong viem giam dau..., nhung cung co the gap do cac thuoc ban khong can don, thuoc bo, vitamin va thuoc thao duoc.

Mot phan ung thuoc xay ra duoc coi la co hai neu no doi hoi phai co su thay doi trong dieu tri (bao gom ca viec phai ngung thuoc hoac giam lieu thuoc), yeu cau nhap vien hoac keo dai thoi gian nam vien. Dieu dang luu y la moi loai thuoc deu khong chi co mot tac dung va deu co nguy co gay ra cac phan ung phu, cung khong co loai thuoc nao thuc su an toan. Mot so phan ung phu do thuoc co the phong tranh duoc, trong khi mot so loai khac thi khong the. Nhung phan ung phu co the phong tranh thuong la nhung phan ung gay ra do cac sai lam trong viec su dung thuoc, tu viec ra y lenh den phan phoi va thuc hien dung thuoc. Nhung tac dung duoc ly thu phat co the du doan truoc cua thuoc thuong khong the phong tranh duoc. Vi du, cac thuoc khang histamin the he cu dung trong dieu tri cac benh di ung thuong gay bieu hien ngay ngat, buon ngu, kho mat kho mieng, nhung tac dung phu nay hoan toan co the du bao truoc nhung khong the phong tranh duoc. Mot loai thuoc du duoc biet truoc co the gay ra cac tac dung phu nhung van co the duoc su dung neu nguoi thay thuoc thay loi ich cua thuoc la lon hon so voi nguy co. Dang tac dung phu nay thuong duoc ghi nhan khong day du do chung thuong nhe va cac thay thuoc da biet truoc su xuat hien cua chung.


Cac phan ung phu cua thuoc
Nguy co xay ra cac phan ung phu cua thuoc tang song song voi so luong thuoc ma nguoi benh su dung. Nhung nguoi lon tuoi thuong co nguy co cao phai chiu cac phan ung phu cua thuoc do day la nhom doi tuong thuong mac cung luc nhieu benh nen phai su dung dong thoi nhieu loai thuoc va kha nang chuyen hoa va dao thai thuoc bi giam sut do suy giam chuc nang gan than. Cac nhom thuoc thuong gay ra cac phan ung phu o nguoi lon tuoi la nhom benzodiazepine tac dung keo dai, cac thuoc chong viem giam dau, thuoc chong dong mau, thuoc loi tieu thiazide, cac thuoc chong lao, thuoc chong ung thu va thuoc chua loan nhip tim.   Cac phan ung di ung chiem khoang 10% tong so cac phan ung phu do thuoc, day la nhung phan ung gay ra theo co che mien dich, do thuoc kich hoat he thong mien dich cua co the san xuat ra cac khang the di ung IgE, nguyen nhan thuong gap nhat la do cac thuoc khang sinh. Phan ung di ung do thuoc thuong chi xay ra khi nguoi benh tiep xuc voi thuoc tu lan thu 2 tro di va cang nhung lan tiep xuc sau thi muc do di ung cang nang. Bieu hien di ung co the tu muc do nhe nhu noi may day, san ngua den muc do nguy hiem, de doa tinh mang nhu soc phan ve, hoi chung Lyell...

Cac phan ung phu khong lien quan den co che mien dich bao gom bieu hien khong dung nap thuoc, nhiem doc thuoc, tuong tac thuoc, tac dung thu phat va phan ung dac ung do thuoc. Bieu hien khong dung nap gay ra do su qua nhay cam cua co the voi cac tac dung duoc ly thong thuong cua thuoc, xay ra ngay ca khi da giam lieu thuoc. Mot so tac dung phu cua thuoc co the gay ra cac hau qua thu phat cho nguoi benh, vi du nhu cac loai glucocorticoid gay suy giam kha nang mien dich khien nguoi benh de mac cac loai nhiem trung nhu lao, virut herpes... Doi khi, tac dung thu phat lai dem den loi ich cho nguoi benh, vi du nhu paracetamol duoc dung voi muc dich ha sot nhung lai co them tac dung giam dau. Phan ung nhiem doc hoac qua lieu xay ra khi nguoi benh su dung lieu thuoc qua cao so voi kha nang dao thai va chuyen hoa thuoc cua co the. Nguoi lon tuoi thuong co nguy co cao bi cac phan ung nhiem doc. Tuong tac thuoc xay ra khi co su tuong tac giua 2 hoac nhieu loai thuoc duoc su dung dong thoi dan den thay doi hieu qua dieu tri hoac doc tinh cua mot hoac nhieu loai thuoc. Luu y la cac loai thuoc bo va thuc pham cung co the tuong tac voi thuoc. Cuoi cung la cac phan ung dac ung do thuoc, day la nhung phan ung tuong doi hiem gap, xay ra do nhung bat thuong mang tinh di truyen trong kha nang chuyen hoa thuoc cua co the. Vi du, do nhung bien doi ve di truyen, mot so benh nhan co the chuyen hoa mot vai loai thuoc qua nhanh hoac qua cham, lam tang nguy co nhiem doc hoac gay that bai dieu tri.

Cac phan ung phu do thuoc, tuy tung dang khac nhau, co the nhe, thoang qua va kho phat hien nhung cung co the rat nang ne, de doa tinh mang hoac gay tan phe cho nguoi benh, co the bieu hien tai cho hoac toan than. Nam he co quan bi anh huong nhieu nhat boi cac tac dung phu cua thuoc la he da niem mac, he than kinh trung uong, he tieu hoa, he tim mach va cac giac quan.

BS. Nguyen Huu Truong Viet Bao (Theo SK&DS)

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