生蛇，唔好隨便買適患療膏用！Zovarix cream doesn't work for your shingles!!

在香港社區藥房工作，往往有令我‘大開眼界’的經驗，這都令我‘讚歎’香港的處方習慣，以下是我遇到的實例



1）年輕女士帶著處方紙來配藥，處方寫著適患療膏（Aciclovir 阿昔洛韋 cream) 陰道用，但處方只有這一個藥物

2）中年男士來我店質詢他醫生開的處方藥，其中一種藥，又是適患療膏（Aciclovir cream) 但醫生指示他要用來搽生蛇的患處

我真的很想衝去他們的醫生，勸他們不要浪費病人的錢和時間，要開藥，就開有效的，例如口服的抗疱疹藥 （oral aciclovir). 外敷的aciclovir 對生殖器疱疹和生蛇這類疱疹沒有療效，就連舒緩痛楚都不能！

要解釋為什麼，連循證都可以省了！口服的 Aciclovir 的生物利用度 （即口服後所剩下的劑量有多少會被身體吸收，從而產生療效）最多是20%，為何你可以預料到外敷的會比口服的更有效？

Working in the community in Hong Kong has surely 'broaden my horizons' of the local prescribing habit.... Here are some cases I have come across;

1) A young lady came in with a prescription for Zovarix, but on the script the application was for vaginal application (no oral antiviral)...

2) A older gentleman came in with loads of prescribed medicine for his shingles, one of them was Zovarix, and he was told to apply to the rash for his shingles


I really wanted to rush to their doctors and tell them, please don't waste the time and money of your patients, if you want to prescribe something, prescribe something that will work. Topical aciclovir (Zovarix) as an antiviral treatment for herpes zoster (shingles) DOES NOT WORK and for herpes simplex virus (HSV 2, in the cases of genital herpes as a sole agent for treatment) IS NOT EFFECTIVE! They don't even provide pain relief! 

You don't really need an evidence based explanation for it; aciclovir as an oral agent has poor bioavailability (max 20%), how do you expect the cream formulation to be more effective than the topical ones?