Penciclovir cream how long to see the effect of no definite time, there are individual differences, clinical common for about 1 week to see the effect. 1. Penciclovir cream instructions do not specify the time of effect of this product, subject to the degree of illness, sensitivity to drugs, treatment timing and other factors, there are individual differences. Clinical generally is about 1 week time to see the effect. 2. Penciclovir cream belongs to a nucleoside class of antiviral drugs, in vitro can inhibit (type I, type II) herpes simplex virus. It is indicated for skin diseases such as herpes simplex on the lips and mouth or face and genital herpes. Adverse reactions can be seen burning sensation, itching and pain in the local area where the drug is used. It is contraindicated in people who are allergic to this product. Be careful not to use on mucous membranes, intraocular and periocular areas. Patients are advised to use Penciclovir Cream reasonably under the guidance of a doctor, do not stop or change the medication regimen on their own.