Aciclovir Cream - Zovirax

What is aciclovir cream and how does it work?

Aciclovir cream, known also as the brand Zovirax, contains 5% aciclovir - an antiviral ingredient used to treat cold sores.

A cold sore is a common skin condition caused by the herpes simplex virus (HSV-1). Commonly affecting the upper lip, a cold sore can appear anywhere on the face.

Once a person is infected with HSV-1, it stays in the body for life, until an outbreak occurs. During an outbreak, the virus ‘awakens’, replicates and moves to the skin surface, where it causes all the recognisable symptoms: tingling, fluid-filled blisters, pain and inflammation.

Aciclovir, as an antifungal treatment, works by stopping the HSV-1 replicating, significantly reducing the lifespan of the cold sore, helping the skin blister, crust and heal much faster.

It works best when used at the earliest sign of an outbreak, i.e. as soon as tingling starts.

Does aciclovir cream actually work

Aciclovir cream has been clinically proven to be effective, but this significantly depends on when you start using it.

Clinical trials have confirmed aciclovir cream reduces healing time by almost a full day, compared to placebo. Additionally, it also significantly reduces pain duration, meaning the burning, throbbing and itching phase of the cold sore is resolved much sooner.

We know aciclovir stops the HSV-1 virus from replicating. If cream is applied after the fluid-filled blisters have already appeared, the virus has already finished most of its replicating.

For this reason, it's crucial to apply the cream as soon as you start feeling the first symptoms, usually tingling (prodrome phase).

Whilst effective, the treatment works locally at the site of application. The cream:

• Cannot cure the virus - the cream stops the active virus from replicating but cannot touch the virus that is dormant (sleeping) within nerve cells.

• Cannot prevent future outbreaks - using the cream for a flare-up does not reduce the frequency of another outbreak

• Cannot be used for severe cases - for those who suffer from frequent outbreaks, or are immunocompromised, oral antivirals are more effective than creams.

How do I use aciclovir 5% cream?

The cream should be applied five times a day, at approximately four hourly intervals. It should be applied directly to the lesions, or the area where tingling occurs, as soon as possible.

Do not wait to see redness/blisters. The cream works more effectively during the prodrome phase, when the tingling starts.

Wash hands before and after using and ensure the cream is not mixed with anything, even water.

Treatment with the cream is usually continued for at least four days, though it can be continued for up to 10 days if needed if healing has not occurred.

The cream should not be applied to mucous membranes (i.e. the mouth, eye or vagina) as it can be irritant.

Zovirax vs generic aciclovir - what's the difference?

The main difference between the branded Zovirax and generic (non-branded) aciclovir is the name on the tube and the price you pay. Both contain the same active ingredient and work in exactly the same way.

The minor differences between the products lies in the inactive ingredients (excipients). Some patients prefer Zovirax for this reason, as the company behind it has invested significantly to optimize their formula so it sits comfortably on sensitive areas like the lip.

Cream vs patches vs tablets - which is right for me?

A cold sore outbreak can be unsightly, uncomfortable and painful. Fortunately, modern treatments have evolved beyond creams, offering a solution for everyone.

The main formulations available are:

• Antiviral creams - like aciclovir cream

• Prescription oral tablets - also containing aciclovir

• Hydrocolloid healing patches

Whilst all three forms are designed to treat an active flare up, they approach the healing from different perspectives:

Aciclovir cream and cold sore patches are available to purchase over-the-counter. Antiviral tablets however, are prescription-only (POM) - these can only be requested either from your doctor or from registered online pharmacies.

Side effects and who shouldn't use it

Whilst a relatively safe treatment, it's important to remember, aciclovir treatment is still a medication, not a cosmetic.

As it is applied directly to the skin, side effects are usually localised to the area where the cream is applied and are generally mild:

• Stinging or burning, expected as the cream starts to work on the virus

• Dryness or flaking can occur as the skin on the cold sore becomes dry as a result of healing.

• Itching, as the skin begins to heal and scab over. It's important to avoid scratching as this can delay healing or spread the virus.

Whilst the cream can safely be used by most, it has its limitations. Patients should speak to a pharmacist if they:

• Are allergic to aciclovir or any of the inactive ingredients. If you experience swelling of the face, throat, lips, tongue with difficulty breathing, wipe the cream off and seek immediate medical attention

• Have sores inside the mouth or eyes. Aciclovir cream must only be used externally on the lips and face

• Have genital herpes

• Are immunocompromised. For anyone with a weakened immune system (due to HIV, chemotherapy or organ transplant), creams may not be strong enough.

The cream can be used during pregnancy as very little amount enters the bloodstream. For breastfeeding individuals, the cream is unlikely to affect a nursing infant, though care should be taken to avoid contact with the treated area.

When a cream isn't enough - speak to our pharmacists

Whilst effective, the cream can only treat the surface of the skin where the blister forms. It has no impact on how often the virus awakens deep within the nerves.

If your cold sore outbreaks are beginning to interfere with your daily life, this is the time to consider internal solutions.

If you experience any of the following, you should consider speaking with your healthcare provider for a more appropriate solution:

• The cream isn’t working fast enough - blisters take longer than 10 days to heal completely, with correct, early use of the cream.

• Severe or widespread outbreaks - blisters form in large clusters spread across the lips, chin or cheeks.

• Outbreaks occur very frequently - more than 6 outbreaks per year.

• You are experiencing complications, such as a secondary bacterial infection.

For these cases, antiviral tablets are available on prescription, containing the same active ingredient (aciclovir). Unlike creams, these work internally and are more effective at stopping virus replication cycles.

For those who suffer from 6 or more outbreaks in a year, the team can also prescribe the tablets as a long-term suppressive therapy - taken everyday to stop future outbreaks.