Acyclovir is effective for herpes zoster virus and herpes simplex virus infections; it is contraindicated in patients who are allergic to it or to propylene glycol. Acyclovir is a synthetic nucleoside antiviral that is selectively phosphorylated by the viral thymine nucleoside kinase, which converts it to a monophosphate. The latter is then converted to diphosphate and triphosphate by cellular enzymes. Acyclovir triphosphate interferes with herpesvirus DNA enzymes, thereby inhibiting viral dna replication. It is used for herpes zoster virus and herpes simplex virus infections, among others. It is contraindicated in patients with known hypersensitivity to acyclovir or propylene glycol. The drug can have adverse reactions such as vomiting, dizziness, stomach upset, headache, nausea, arthralgia, diarrhea, decreased white blood cells, proteinuria, insomnia, loss of appetite, itchy skin, and acne. There are interactions when combined with propofol, zidovudine and other drugs, so you should consult a professional doctor or pharmacist before use. It should be used with caution in the following cases: in the presence of dehydration of the body; the elderly; lactating women; hepatic and renal insufficiency. The drug can pass through the placenta, so pregnant women should use it after careful consideration. If you need to use the drug, please be sure to strictly follow the instructions of the doctor or pharmacist to take medication, do not self-medication.