Anviro is valaciclovir 500 mg, an antiviral tablet for herpes infections — cold sores, genital herpes, shingles and chickenpox. It is not an HIV medicine. Its advantage over older aciclovir is that it needs taking two or three times a day rather than five.
What is Anviro?
Anviro contains valaciclovir 500 mg. The South African Medicine Price Registry lists it as a Schedule 4 tablet (prescription-only).
Valaciclovir is a prodrug of aciclovir — inactive as swallowed, and converted into aciclovir by the liver and intestine after absorption. That extra step exists to solve a practical problem: aciclovir taken by mouth is absorbed poorly, which is why it has to be taken four or five times a day. Valaciclovir is absorbed three to five times better, so the same amount of active medicine reaches the blood from fewer doses.
The clinical effect is identical, because the working molecule is the same. What differs is convenience — and with a medicine that must be taken on time to work, taking it twice a day instead of five times is not a small thing.
Aciclovir itself works with unusual precision. It is activated only by an enzyme that herpes viruses produce and human cells do not, so it concentrates inside infected cells and largely leaves healthy ones alone. Once activated it blocks the viral enzyme that copies viral DNA. That selectivity is why an antiviral this effective is also this well tolerated.
What is Anviro commonly used for?
Valaciclovir treats infections caused by the herpes family of viruses:
- Cold sores (herpes simplex on the lips and face), particularly frequent or severe outbreaks.
- Genital herpes — treating outbreaks, and suppressive treatment taken daily to prevent recurrences.
- Shingles (herpes zoster). Started within 72 hours of the rash appearing, it shortens the illness and may reduce the chance of lasting nerve pain.
- Chickenpox, particularly in adults and adolescents, where the illness tends to be more severe.
- Herpes infections in people with weakened immunity, including advanced HIV, transplant recipients and people on chemotherapy.
- Reducing transmission of genital herpes to a partner — valaciclovir taken daily has been shown to lower that risk, which is a use aciclovir is not usually prescribed for.
- Preventing outbreaks during periods of immune suppression or around certain procedures.
It does not cure herpes. These viruses remain in nerve tissue permanently after the first infection. Valaciclovir controls and suppresses outbreaks; nothing available eradicates the virus.
It has no effect on HIV. Valaciclovir appears in the antiviral category because it is an antiviral, and it is often prescribed to people living with HIV — herpes outbreaks are more frequent and more severe when immunity is reduced. But it is not an antiretroviral and is never part of HIV treatment itself.
Timing matters more than with most medicines. Start it at the very first sign of an outbreak — the tingling, itching or burning before a blister appears — and within 72 hours of a shingles rash. Started late, the benefit shrinks considerably.
How Anviro fits into this medicine category
| Group | Examples | Target |
|---|---|---|
| Herpes antivirals | Valaciclovir (Anviro), aciclovir, famciclovir | Herpes simplex, varicella zoster |
| Antiretrovirals | Dolutegravir combinations (Acriptega) | HIV |
| Hepatitis antivirals | Tenofovir-containing products (Hetemcit) | Hepatitis B and C |
| Topical antivirals | Aciclovir cream | Cold sores, applied to the lesion |
| Antibiotics | Penicillins, macrolides | Bacteria — no effect on viruses |
Valaciclovir and the antiretrovirals share a category and nothing else. See the HIV and antiviral medicines hub.
What to check before using Anviro
Drink plenty of water while taking it. This is the most practical precaution. Aciclovir is cleared by the kidneys and, at higher doses or when dehydrated, can crystallise in them. Good fluid intake largely prevents this.
Tell your doctor or pharmacist if you:
- Have kidney disease or reduced kidney function. This is the main check — the dose must be reduced, and most problems with this medicine trace back to it.
- Are elderly. Kidney function declines with age even without a diagnosis, and older people are more prone to the confusion and drowsiness that follow if levels build up.
- Have a weakened immune system from HIV, chemotherapy or transplant medicines. Higher doses are sometimes used, and a rare blood disorder has been reported at very high doses in severely immunocompromised patients.
- Take medicines affecting the kidneys, including regular anti-inflammatories, or take probenecid or cimetidine.
- Are pregnant or breastfeeding. Valaciclovir has a reasonable record of use in pregnancy, but the decision should be your clinician’s.
- Are treating a child, where dosing is by weight and age.
Practical points:
- Start as early as possible in an outbreak.
- Take it with or without food, at evenly spaced times.
- Complete the course, even once the rash begins to settle.
- Do not share it, and do not save leftover tablets for a future outbreak without advice — though for recurrent cold sores or genital herpes, some doctors deliberately provide a supply to start at the first symptom. If that is your arrangement, follow it.
Possible cautions and when to ask a pharmacist or doctor
Valaciclovir is generally very well tolerated. The commonest effects are headache, nausea, abdominal pain, dizziness and tiredness.
Seek medical advice promptly for:
- Confusion, hallucinations, agitation, tremor or unsteadiness. Uncommon, occurring mainly with reduced kidney function or in older people, and reversible when recognised.
- Reduced urine output, swollen ankles or unusual tiredness — possible kidney effects.
- Unusual bruising, bleeding, or small purple spots on the skin, particularly if you are immunocompromised.
Get emergency help for swelling of the face, lips or tongue, difficulty breathing, or a widespread blistering rash.
Contact your doctor if:
- Shingles affects your face, especially near an eye. This needs urgent assessment — eye involvement can threaten sight.
- The rash is spreading, very painful, or not improving after several days.
- You develop fever, severe headache, neck stiffness, confusion or drowsiness.
- The skin around the rash becomes red, hot, swollen or oozing — bacterial infection on top.
- Outbreaks recur frequently. Daily suppressive treatment often works better than treating each episode, and also reduces the risk of passing genital herpes to a partner.
- Pain persists after shingles has healed. Post-herpetic neuralgia is common and treatable.
- You are pregnant and have genital herpes, which needs a plan for delivery.
Related medicine guides
Frequently asked questions
What is Anviro 500 used for? Herpes infections — cold sores, genital herpes, shingles and chickenpox. It contains valaciclovir 500 mg.
Is Anviro an HIV medicine? No. It is a herpes antiviral with no effect on HIV, though it is often prescribed to people living with HIV for herpes outbreaks.
Is it the same as aciclovir? Valaciclovir converts into aciclovir in the body. The active medicine is the same; valaciclovir is absorbed far better, so it is taken fewer times a day.
Does it cure herpes? No. It controls and suppresses outbreaks. The virus remains in the body for life.
When should I start taking it? At the first tingling or burning, and within 72 hours of a shingles rash appearing. Starting late reduces the benefit considerably.
Can I still pass on herpes while taking it? Daily suppressive treatment reduces transmission risk but does not remove it. Continue other precautions.
Why do I need to drink more water? It is cleared by the kidneys and can crystallise in them if you are dehydrated, particularly at higher doses.
Can I take it every day? Yes, for suppressive treatment of recurrent genital herpes or cold sores — on a doctor’s direction, with kidney function considered.