Acyclovir — what it treats and how it helps

Acyclovir is a common antiviral that fights herpes viruses. Doctors prescribe it for cold sores (HSV-1), genital herpes (HSV-2), and shingles (herpes zoster). It won’t cure the virus, but it shortens outbreaks, eases pain, and helps prevent repeat episodes when used regularly.

People like acyclovir because it’s been around for decades and has a clear safety record when used correctly. Still, how you take it and when you start treatment matters. Starting at the first sign of a flare-up gives the best results.

Common dosages and forms

Acyclovir comes as tablets, capsules, oral suspension, topical cream, and IV in hospitals. Typical adult oral doses look like this: for a simple cold sore or an episodic genital outbreak, many prescribers use 400 mg three times daily for 5–10 days, or 200 mg five times daily for 5 days. For daily suppression of genital herpes, 400 mg twice daily is common. For shingles, the usual adult dose is 800 mg five times daily for 7–10 days. Topical cream (5%) is often applied five times a day for 4 days for labial herpes.

If you have kidney disease your doctor will lower the dose. Children and infants use different weight-based regimens; don’t guess — check with a pediatrician. IV acyclovir is reserved for severe infections or immunocompromised patients and must be given in a hospital setting.

Side effects, safety checks and buying tips

Most side effects are mild: nausea, headache, dizziness, or tiredness. A less common but serious issue is kidney stress, especially if you’re dehydrated or take high doses. Drinking water when you take acyclovir helps reduce that risk. Rarely, people with severe kidney problems can have confusion or tremors — tell your doctor right away if you notice sudden mental changes.

Drug interactions are limited but can matter. Drugs that affect kidney function or blood levels of other medicines should be checked with a pharmacist. Pregnant or breastfeeding people should discuss risks and benefits with their clinician before starting treatment.

Want to buy acyclovir online? Follow these rules: buy only from licensed pharmacies, never use sites that skip prescriptions for oral tablets, check for a real address and pharmacist contact, read recent customer reviews, and use secure payment methods. For Canadian pharmacies look for clear licensing info and options to fax or upload a prescription. Avoid prices that look too good to be true — they often are. If you’re crossing borders, remember customs rules can delay or block shipments.

If you’re unsure whether acyclovir is right for you, talk to a healthcare pro. They’ll match the dose and form to your health, age, and kidney function so treatment is both safe and effective.