Acyclovir — what it treats, how it works, and when to see a doctor

Want a quick, no-nonsense look at acyclovir? This antiviral is a go-to for herpes viruses: cold sores, genital herpes, chickenpox and shingles. It won’t cure the virus, but it cuts the length and severity of outbreaks when taken early. Read on for real-world dosing tips, side effects to watch for, and simple ways to save when you need a prescription.

How acyclovir works and common uses

Acyclovir blocks viral DNA replication so infected cells make fewer new viruses. Doctors prescribe it for: cold sores (HSV-1), genital herpes (HSV-2), shingles (herpes zoster), and chickenpox in kids or adults at risk. Forms include topical cream, oral tablets/suspension, and IV for severe cases in hospitals.

Typical dosing examples: for a first genital herpes outbreak adults often take 200 mg five times daily or 400 mg three times daily for 7–10 days; for shingles doses are usually 800 mg three times daily for 7–10 days. For cold sores topical cream may be applied at first tingle. Exact dose depends on age, kidney function, and the infection—so follow your prescriber's plan.

Safety, side effects, and practical tips

Most people tolerate acyclovir fine. Common side effects are nausea, headache, and tiredness. Rare but serious issues include kidney problems (especially if you’re dehydrated or have pre-existing kidney disease) and confusion in older adults. If you notice rash, swelling, breathing trouble, or sudden changes in behavior, stop the drug and get medical help fast.

Drug interactions are limited, but dosing needs adjustment when kidneys don’t work well. Pregnant people should only take acyclovir if their doctor recommends it—in many cases the benefits outweigh risks, but always check. Acyclovir passes into breast milk, so talk to your clinician before breastfeeding on treatment.

Wondering about valacyclovir? It’s a prodrug that turns into acyclovir in the body and typically needs fewer daily doses. Your doctor may choose one over the other based on convenience and cost.

Need to buy acyclovir? It’s a prescription medicine. To save money: compare prices across licensed pharmacies, ask for the generic (acyclovir is far cheaper than brand names), check manufacturer coupons or patient assistance programs, and consider larger quantity or longer prescriptions if your doctor agrees. Avoid unverified online sellers—if the price sounds impossibly low, the product might be fake. Look for pharmacies with clear contact details, verified licenses, and secure payment methods.

Short, practical checklist: 1) Start treatment at first sign of outbreak for best results. 2) Drink enough water while on acyclovir, especially if you’re older. 3) Tell your prescriber about kidney issues or other meds. 4) Buy only from licensed pharmacies and compare prices to save. If you're unsure about a dose or side effect, call your pharmacist or doctor—they’ll help you sort it out quickly.