- Tac dung kich thich heM
ehe'ph6m va lieu dung
- Che ph~m: dung dich tiem, ong Img/ mL.
- Lieu dung: tiem duoi da, tiem biip 0,5- Img/ l~n, 1- 2 l~n/ 24h.
I
4.1.2. Betanechol (Urecholin)
Betanechol la d~n xuat cua acetylcholin ben vtrng hon acetylcholin, co th~ dung duong tiem hoac duong uong. Tac dung tuong tu acetylcholin nhung it UtC dung tren h~ N, it tac dung khong mong muon tren tim. Thuoc co tac dung uu tien tren co tron tieu hoa va bang quang.
Thuoc thuong dung dieu tri liet ruot, tao bon, trudng bung, dlly hoi, bi ti~u
~?
sau mo.
Lieu dung: 10-50mgl 24h.
4.1.3. Metacholin, carbacholin
Metacholin va carbacholin deu la chat t6ng hop, ben virng, co th~ dung duong tiern hoac udng. Thuoc co UtCdung tuong tu acetylcholin. Tuy nhien, do it bi ph an huy bdi cholinesterase nen tac dung manh, keo dai va dQCtinh cao hon,
Lieu dung:
Carbacholin: uong' 0,5- Img/lan, tiern dudi da 0,25- 0,5mglllln, 1- 2l11nl24h. Metacholin: udng hoac tiern 15mgl Ian, 1- 2Mni24h.
4.2. Thuoc tacdung tren h~ M
4.2.1. Pilocarpin Ngu{j'n goc
Pilocarpin dung lam thuoc duoc chiet tit thuc vat hoac t6ng h<;lphoa h9C.
DUlJcdl}ng h(}c
Hap thu dU<;lCca. qua dUdng uong va tiem. Sau khi uong khoang 1 gid, thuoc d~t n6ng dQ toi da trong huye't tudng. Sau khi nh6 mAt 10- 30 ph1.it,xuat hi~n tac d\mg va duy tri dU<;lC4- 8 gid. D~ng gel tac d\lng keo dai 18- 24 gid. Thai tru chu yeu qua nuoc ti~u phftn Ion d~ng da chuy~n hoa.
Ttic dung
Thuoc kich thich tr\ic tie'p h~ M. Bi~u hi~n giong acetylcholi~ nhung ben vilng hdn. Tac d\lng cua pilocarpin n6i b~t nhat la tren cd trdn va tuye'n ngo~i tie't.
- Tren mAt: thuoc lam co cd vong mong mAt nen gay co d6ng tl:i va giam nhan ap. Tac d\lng nay cang r6 khi bi tang nhan ap.
- Tren cd trdn: thuoc lam tang nhu dQng d~ day, rUQt, co cd vong bang quang, t1.iim~t, co thAt cd trdn phe quan.
- Tulln hoan: tic che tim, gian m~ch va h~ huyet ap.
Chi dinh.
Nh6 mat dieu tri glaucom, viern mong' mat hoac gian d6ng ti'i. Co that mach ngoai vi.
Giam chuc nang ngoai tiet.
Giam chuc nang co tron (liet ruot, liet bang quang sau m6).
Chfingchi dinh. (chuyeu vdi duong toan than) Hen phe.quan,
Ha huyet ap.
Loet da day, ta trang.
Chlphdm valie'udung
- Che pham:
Vien nen 5mg. Dung dich nho mat 1- 4%. Gel b6i mat 4%. - Lieu dung:
Duong uong, tiem thuong dung 15- 30mg/ 24h.
Duong nho mat: 1- 2 giot/ Ian, 3- 4 lllnl 24h. Dang gel Llan/ ngay.
4.2.2. Caethuoc hluu:
Musearin
La alcaloid co trong nam dQcAmanita muscaria, co tac dung kich thich h~ M manh hen acetylcholin khoang 5 Ian. Do dQctinh cao nen kh6ng duoc dung trong dieu tri, (Trong thuc te hay gap ngQ dQcmuscarin do an phai nam dQcco chua chat nay).
Areeolin
La alcaloid co trong hat cau, tac d\mg gi5ng pilocarpin nhung hi~n nay hllu nhu kh6ng dung trong dieu trj vi dQc.
4.3. Thuoc khimg cholinesterase
Thu5c khang cholinesterase (enzym thuy phan acetylcholin) lam tang IUQngacetylcholin nQi sinh dsynap thlln kinh d~n den gian tiep gay cUdng h~ cholinergic ca h~ M va h~ N. Chia 2 nhom:
Khang cholinesterase thu~n nghjch: neostigmin, physostigmin.
Khfmg cholinesterase kh6ng thu~n nghich: alkylphosphat, rat it dung dieu trj vi dQctinh cao. Hi~n nay chu yeu lam thu5c tru sau.
4.3.1. Thuoc hluing cholinesterase thuiin nghicb
4.3.1.1. Neostigmin (Prostigmin)
Duacd9ng hoc
Neostigmin la amin bac 4, kh6 hap thu qua duong tieu h6a, duong tiem hap thu nhanh hon. Lien ket vdi protein huyettuong tu 15- 25%, kh6 qua hang rao mau nao, nhau thai va sua me. Chuyen h6a bdi esterase dhuyet tuong va mot phan d gan. Thai tru chu yeu qua nude ti~u dang chua chuyen h6a, thoi gian ban thai 1- 2 gio.
Tac dung
Thuoc khang cholinesterase lam giam toe d9 thuy phan acetylcholin d ca synap than kinh trung uong va ngoai vi nen gian tiep kich thich ca h~ M va N.
- Tac dung tren h~ M: gay cuong ph6 giao cam giong acetylcholin nhung tac dung cua neostigmin thuong on hoa va ben vfing hon nen duoc dung nhieu hon (xem acetylcholin).
- Tac dung tren h~ N:
+ Thuoc kich thfch h~ N d than kinh trung uong gay tinh trang hung phan, lieu cao gay co giat.
+Thuoc kich thfch h~ N d h~ch th\iC v~t gay cudng ph6 giao cam. Khi h~ Mbi phong be bAngatropin thi xuat hi~n tac d-.,mgcudng giao cam.
+Thuoc kich thich h~ N d cd xudng gay tang co cd, c6 th~ dung lam thu6c ch6ng nhuQccd ho;Ilcgiai d9Cthu6c mem cd cura ch6ng khli c\ic.
Chi dinh
B~nh glaucom.
Giam chile nang cd trdn (truDng b-.,mg,tao b6n, li~t rU9t, li~t bang quang sau m6).
Giam chilc nang cd van (nhuQcCd,li~t Cd). Giai d9c thuoc mem cd cura lo~i chong khli c\ic.
Tac dlfng khong mong muon
Tren thlln kinh trung udng: gay tr~ng thai kich thich, 10 au, ch6ng m;Ilt, ban chan. Khi dung qua lieu gay co gi~t, hon me.
Tren tuyen ngo~i tiet: tang tiet nUDcbQt,nUDcmlit,nUDcmlii, mo hoi... Tren tulln hoan: ch~m nhip tim va h~ huyet ap.
Tren ho hap: co thlit khi phe quan.
Tac d\mg khong mong muon khac: tieu chay, co cd...
Khi qua lieu neostigmin n6i rieng va cac thu6c khang cholinesterase n6i chung, dung atropin giai d9C.
Ch{j'ngchi dinh
TAcruot va tAcduong tiet nieu.
Che'phiim va lieu dung
- Che pham: dang tiem 0,251mL; 0,5mgl mL; 5mg/lOmL va 10mg/lOmL.;
dang vien nen 15mg.
- Lieu dung: tiem 0,5-5mgl 24h; uong 15mgl Ian, 3- 4 lftnl 24h.
4.3.1.2. Physostigmin (Eserin)
La alcaloid c6 trong hat cayPhysostigma venenosum, ho Dau.
Tac dung khang cholinesterase manh, d(>ctinh cao. Thuong dung nho mat dieu tri glaucom, viem giac mac, gian d6ng ti'i.
Dung dich nho mat 0,25%; 0,5% va 1%.
4.3.1.3. Cdc thuoc khac
Cac thuoc deu c6 tac dung va co che tac dung tuong tu nhu neostigmin,
chu yeu dung dieu tri nhuoc co: galantamin, pyridostigmin, edrophonium,
ambenonium.
4.3.2.Khiing cholinesterase kh6ng thtuin nghich. .
Nh6m alkylphosphat (phospho hiai cd)
Dijc diem
Alkylphosphat phosphoryl h6a manh cholinesterase tao phuc ben virng, kh6 thuy phan d~ h6i phuc cholinesterase. Vi vay, thuoc gay tich tu acetylcholin
dca.trung uong va ngoai vi gay d(>ctinh cao vdi co th~.
Hi~n nay, nh6m nay it dung trong lam sang (chi c6 echothiopat dung dieu tri glaucom). Phftn IOndung d~ dung di~t can trung, tru sau, di~t co va lam chat d(>ch6a h<;>c.
Cac alkylphosphat hap thu dUQcqua da va niem m~c nen khi dung (tru sau di~t co)phiii het suc th~ tr<;>ngvi c6 th~ hap thu vao mau va gay d(>cvoi Cdth~.
Tri~u chitng ngf) df)c
Tri~u chung ng(>d(>cphospho huu cd (do kich thich m~nh h~Mva N):
Kich thich h~ M:co d6ng ti'i, tang tiet dich (chay nuoc mAt, mui, tang tiet nuoc b<;>t,m6 hoi), tieu chay, non, trl,lYtim m~ch, co thAt phe quan gaykh6 thd.
Rich thich h~ N d thftn kinh trung udng va ngo~i vi: hi l§.n, n6i liu nhiu, mat phan x~, han me, chu(>trut, co gi~t.
Khi ng(>d(>cthuoc ma khong cap cuu kip thdi, b~nh nhan se chet do li~t ho hap va trl,lYtim m~ch.
Giiii d{jc
- Dung thuoc phong be he M: atropin sulfat ligu cao tiem tinh mach 1- 2mg/lful cu 5- 10 phut tiem mot l~n cho tdi khi mat het cac trieu chung kich thich he M. Ngay dau c6 th~ dung tdi 50mg. T6ng lieu dung c6 th~ tdi 200mg. - Dung thuoc hoat h6a cholinesterase: pralidoxim tiem tinh mach 1- 2mg/
Ian, neu c~n c6 th~ tiem nhac lai, 4.4. Thuoc kich thich h~ N
4.4.1. Nicotin
DUlJc d{jng hoc
Nicotin hap thu qua mieng, qua 6ng tieu h6a va qua da. Khoang 80- 90% duoc chuyen h6a trong co th~, chu yeu d gan, mot phan d than va ph6i. Thoi gian ban thai khoang 2 gio. Ca nicotin va chat chuyen h6a dgu thai tru nhanh qua than. T6c d9 thai trir phu thuoc vao pH nude ti~u, khi pH nude ti~u kiem thi t6c d9 thai tru cham, Nicotin cling thai mot phan qua sua me.
Ttic dlfng va cCIche'
- Tren than kinh trung udng, nicotin kich thich h~ nicotinic d th~n kinh trung udng gay hung phan, kich thich ho hap. Ligu cao gay co gi~t.
- Tren th~n kinh th1.jCv~t, nicotin kich thich h~ nicotinic d cac h:;tch th1.jC v~t, bi~u hi~n:
+ Tren tu~n hoan: gay tac d\lng 3 pha: khdi d~u, nicotin kich thich h~ N d h:;tchph6 giao cam va trung tam uc che tim d hanh nao nen lam tim d~p ch~m, h:;thuyet ap; tiep theo kich thich h~ N d h:;tchgiao cam, tuy thu<;Jng th~n va trung tam v~n m:;tchlam tim d~p nhanh, tang huyet ap; cu6i cung gay li~t h:;tchdo kich thich qua muc, lam h:;thuyet ap keo dai.
+Ngoai ra, gay gian d6ng ti'i, tang nhu d9ng rU9t, tang tiet dich.
Nicotin gay nghi~n, khong dung trong digu tri, chi dung trong phong thi nghi~m d~ nghien cuu cac thu6c tac d\lng tren h:;tch.
Tac d\lng khong mong mu6n
Cac tri~u chung cap tinh: bu6n non, non, dau b\lng, tieu chay, toat m6 hoi, dau d~u chong m:Itt,r6i lo:;tnchuc nang nhin, nghe, roi lo:;tntam th~n, kho thd, tr\lY tim m:;tch,huyet ap.
4.4.2. Cac thuoc khac