With several OTC topical creams and prescription antiviral medications available for the treatment of cold sores, pharmacists are often the first person patients turn to when seeking advice and treatment for their symptoms. 

Acyclovir is an antiviral medication that is commonly used in the treatment of cold sores. It works by inhibiting the replication of the herpes simplex virus (HSV), which causes cold sores. Here are some important things to know about the use of acyclovir in treating cold sores: 

Acyclovir is most effective when used early: The earlier acyclovir is started, the more effective it is in treating cold sores. Ideally, treatment should be started as soon as the patient notices the first symptoms, such as tingling or itching around the mouth. 

Acyclovir can be taken orally or topically: Acyclovir is available in both oral and topical formulations. Oral acyclovir is usually prescribed for patients with severe or frequent outbreaks, while topical acyclovir is recommended for patients with mild to moderate symptoms. Both forms of acyclovir have been shown to be effective in reducing the duration and severity of cold sores. 

Acyclovir can treat HSV-1 and HSV-2: Decreasing the severity and lengths of outbreaks, acyclovir has been shown to decrease pain in three days and speed healing in less than five days. 

Acyclovir may cause side effects: Like all medications, acyclovir can cause side effects. The most common side effects of acyclovir include nausea, vomiting, diarrhoea, and headache. In rare cases, acyclovir can cause more serious side effects, such as kidney damage or allergic reactions. Advise patients to report any unusual symptoms or side effects immediately. 

Patients should be advised that they may still experience outbreaks in the future, and that prevention measures may be necessary to reduce the risk of recurrence.