Acyclovir is an antiviral medication used to treat infections caused by the herpes virus. It is available in different forms, including oral, topical, and intravenous. The safety of long-term use of acyclovir has been a subject of research.

According to Drug Patent Watch [1], acyclovir has been on the market since 1982 and has a good safety profile. It is considered a well-tolerated drug, and adverse effects are usually mild and transient. The most common side effects of acyclovir include nausea, vomiting, diarrhea, headache, and dizziness.

A study published in the Journal of Infectious Diseases [2] evaluated the safety of long-term acyclovir use in patients with recurrent genital herpes. The study followed 137 patients for up to 10 years and found that long-term acyclovir use was safe and well-tolerated. No serious adverse events were reported, and the incidence of side effects decreased over time.

Another study published in JAMA Ophthalmology [3] investigated the safety of long-term acyclovir use in patients with herpes simplex virus (HSV) keratitis. The study followed 48 patients for up to 10 years and found that long-term acyclovir use was safe and effective in preventing recurrent HSV keratitis. No significant adverse events were reported.

In conclusion, the available evidence suggests that long-term use of acyclovir is safe and well-tolerated. However, as with any medication, patients should discuss the risks and benefits of long-term acyclovir use with their healthcare provider.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/ACYCLOVIR
[2] https://pubmed.ncbi.nlm.nih.gov/2895840/
[3] https://jamanetwork.com/journals/jamaophthalmology/fullarticle/415931