Cou 70: diphenylhydantoin: TD, TD ko mong muon và coc TT can chy y?

Diphenylhydantoin la 1 trong nhung thuoc co tac dung tot chua moi the dong kinh, tru the dong kinh ko co co giat

* Toc dung:

- Phenytoin co tac dung chong con dong kinh nhung ko gay uc che toan bo he than kinh. Lieu doc cun goy kick thick. Toc dung tron con co giat dong kinh cung giong nhu phenobarbital, nhung ko gay an than va ngu

- Phenytoin co tac dung on dinh mang Tb than kinh va co tim, lam giam luong Na+ trong dien the hoat dong trong khu cuc do coc chat hua hoc

* toc dung ko mong muon:

- Da va niem mac: viem loi qua san, man da, lupus ban do

- Mou: thieu mou hong cau to do thieu acid folic, giam bach cau...

- Tieu hoa: non, con dau bung cap

- than kinh - tam than: leein quan den nong do thuoc trong mou

+ <= 20microgam/ml co td dtri

+ = 30 làm dung giat nhon cau

+ = 40 gay mat phoi hop dong tac

+ > 40 goy roi loan tom than

- xuong: cui xuong or mem xuong, co the la do roi loan chuyen hoa vitamin D, nhat la khi phoi hop voi phenolbarbital

* tuong toc thuoc:

- cloramphenicol, dicumarol, isoniazid, cimetidin co the lam tang nong do cua phenytoin trong huyet tuong do lam giam chuyen hoa. Trai lai, carbamazepin lam tang chuyen hoa nen lam giam nong do phenytoin trong huyet tuong

- salicylat, tolbutamid, sulfisoxazol tranh chap voi phenytoin o vi tri gan vao pr huyet tuong