Acyclovir is an antiviral medication that is used to treat viral infections such as herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections. According to the sources provided, there are some potential side effects associated with acyclovir use.

The most common side effects of acyclovir include nausea, vomiting, diarrhea, and headache [2][3]. These side effects are usually mild and go away on their own within a few days. However, if these symptoms persist or become severe, it is important to contact a healthcare provider.

Other potential side effects of acyclovir include dizziness, confusion, and hallucinations [2]. These side effects are rare but can be serious, especially in older adults or people with kidney problems. If any of these symptoms occur, it is important to seek medical attention immediately.

In rare cases, acyclovir can cause serious side effects such as allergic reactions, seizures, and kidney damage [2][3]. These side effects are more likely to occur in people with pre-existing medical conditions or those who are taking other medications that interact with acyclovir. It is important to discuss any medical conditions or medications with a healthcare provider before starting acyclovir treatment.

In conclusion, while acyclovir is generally safe and effective for treating viral infections, there are potential side effects that should be considered. The most common side effects are mild and go away on their own, but serious side effects such as allergic reactions and kidney damage can occur in rare cases. It is important to discuss any concerns or questions about acyclovir treatment with a healthcare provider.

Sources:
[2] Mayo Clinic. (2021). Acyclovir (Oral Route, Intravenous Route). https://www.mayoclinic.org/drugs-supplements/acyclovir-oral-route-intravenous-route/side-effects/drg-20068393?p=1
[3] RxList. (2021). Zovirax. https://www.rxlist.com/zovirax-drug.htm