Acyclovir is an antiviral medication used to treat infections caused by herpes viruses. It works by preventing the virus from multiplying and spreading. According to DrugPatentWatch [1], the onset of action of acyclovir is within 24 hours of starting treatment. However, the full therapeutic effect may take up to five days.

It is important to note that acyclovir is not a cure for herpes infections, but it can help to reduce the severity and duration of symptoms. The medication is most effective when taken at the first sign of an outbreak, such as tingling or burning sensations on the skin.

Drugs.com [2] recommends taking acyclovir exactly as prescribed by a healthcare provider. The medication can be taken with or without food, but it is important to drink plenty of water while taking it to stay hydrated. Patients should continue taking the medication for the full course of treatment, even if symptoms improve before the medication is finished.

ForHims [3] notes that valacyclovir, a medication similar to acyclovir, may work more quickly than acyclovir. Valacyclovir is converted to acyclovir in the body, but it has a longer half-life, meaning it stays in the body longer and may require less frequent dosing. Valacyclovir may also be more effective at preventing the spread of herpes to sexual partners.

In conclusion, acyclovir typically starts working within 24 hours of starting treatment, but the full therapeutic effect may take up to five days. It is important to take the medication exactly as prescribed and to continue taking it for the full course of treatment. Patients should also stay hydrated while taking acyclovir. Valacyclovir may work more quickly and be more effective at preventing the spread of herpes to sexual partners.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ACYCLOVIR
[2] https://www.drugs.com/tips/acyclovir-patient-tips
[3] https://www.forhims.com/blog/how-long-does-valacyclovir-valtrex-take-to-work